Expansive Soil

In Kingdom of Saudi Arabia, there are several areas where expansive soil exists in the form of variable-thicknesses layers in the developed regions. Severe distress to infrastructures can be caused by the development of heave and swelling pressure in this kind of expansive shale. Among the various techniques for expansive soil mitigation, the removal and replacement technique is very popular for lightly loaded structures and shallow foundations. This paper presents the result of an experimental study conducted for evaluating the effect of type and thickness of the cushion soils on mitigation of swelling characteristics of expanded shale. Seven undisturbed shale samples collected from Al Qadsiyah district, which is located in the Tabuk town north Kingdom of Saudi Arabia, are treated with two types of cushion coarse-grained sediments (CCS); sand and gravel. Each type is represented with three thicknesses, 22%, 33% and 44% in relation to the depth of the active zone. The test results i...

Illuri, Hema K. and Nataatmadja, Andreas (2007) Shrink-swell and cracking of sand-bentonite mixes with EPS inclusion (Contraerhinchese y el agrietarse de las mezclas de la arena-bentonita con la inclusion de EPS) . In Romeo, Isaura and Englert, Carlos, Eds.

This paper describes how three reconstituted soils with PI ranging from the laboratory by mixing fine sand and sodium rich bentonite. A series these soils, which were mixed with recycled Expanded Polystyrene (EPS). By varying the EPS content, compaction tests ...

Clayey soils often exhibit low strength and high plasticity, challenging subgrade stability in road infrastructure and prompting the search for sustainable stabilization solutions. This study evaluated the efficacy of recycled crumb rubber (CR) and eucalyptus ash (EA) as additives to improve the geotechnical properties of a problematic clayey soil. A laboratory program involving Atterberg limits, compaction, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) tests was conducted on samples with varying percentages of CR, EA, and their combinations. Key results demonstrated that CR addition, particularly at 15%, significantly enhanced soil strength, increasing CBR by 41.3% and UCS by 38.9% relative to untreated soil. Optimized CR-EA combinations (e.g., 10% CR + 10% EA) also yielded substantial improvements, with CBR increasing by 30.9% and UCS by 26.3%. However, EA addition generally increased the optimum moisture content, which may cause a potential practical inconvenience, and excessive overall additive levels could negatively impact performance. The findings highlight CR and EA's potential as effective soil stabilizers, emphasizing the critical role of optimizing additive proportions for enhancing clayey soils in road subgrades.

For several decades, lightweight material applications have been extensively studied. Modifying various types of soil with EPS beads or lightweight geomaterials is an alternative construction material on site that can reduce excessive problems such as large deformation and lateral pressure. This study aims to examine the strength characteristics of lightweight geomaterials, namely lightweight modular block/LMB. LMB is composed of EPS beads, dredged soil, and cement. The cement amounts are 3%, 5%, 7%, and 9%, with EPS variations of 0.5% and 0.75% to the mixture weight. Laboratory tests were conducted to investigate the strength with unconfined compression and undrained direct shear tests. Before testing, the specimens were made using the one-layer static compaction method and were cured for 7, 14, and 28 days. This paper also presents explanations related to the specimens making and treatment by providing preliminary test results to compare the effectiveness of the three-layer and one-layer methods. Moreover, the curing treatments to avoid cracking were explained explicitly. The result shows linearity between both increasing the amount of cement and adding more curing time to the increase of the strength parameter. In contrast, adding more EPS decreased the strength, but adding cement helped increase the strength parameter with a remarkable value at C7% and C9%. Increasing the amount of EPS also reduced the density of the mixture by 18%-29%.

Expansive soil is a form of soil that can expand and contract, changing its volume. Montmorillonite, a mineral with the ability to dissolve in water, makes up the majority of these kinds of soils, and by increasing the volume of the soil, it causes the soil to heave. Expansive soils could be a substantial concern for engineered buildings due to their capacity to adjust to seasonal variations by contracting or expanding moisture content. Many researchers focused on soils that were swollen and looked at how they behaved as well as how they could be improved. In this study, the work depends on inserting micropiles with different depths and configuration widths to investigate which depth and configuration can be obtained to improve the bearing capacity of foundations on expansive soil. The main purpose of this study is to reinforce the expansive soil with micro-piles with different depths (1B, 2B, and 3B) and different configuration widths (under footing only, 1B and 2B). It was concluded that the soil reinforced with micro-piles improved the load-bearing capacity of the expensive soil and decreased the swell pressure. The increasing depth of the micropiles 2B to 3B (B is the width/diameter of the foundation) can increase the bearing capacity by just 6%; therefore, increasing the depth beyond 2B is not beneficial. Also, the increase in width of the configuration of the micro piles from 1B to 2B increases the bearing capacity by just 4%; therefore, the increase in width greater than 1B is not valid.

Expansive soils are suitable as backfill and buffer materials in engineered barrier systems to isolate high-level nuclear waste in deep geological formations. The canisters containing nuclear waste would be placed in tunnels excavated at several hundred meters depth. The expansive soil would be used for tunnel backfill and should provide enough swelling capacity to support the tunnel walls and thereby reduce the impact of the excavation damaged zone on permeability in the near-field that could affect the long-term barrier performance. In addition to their swelling capacity, expansive soils are characterized by accumulating irreversible strain upon suction cycles and by effects of microstructural swelling on water permeability that for backfill or buffer materials can significantly delay the time to reach full saturation. To simulate these characteristics of expansive soils, a dual structure constitutive model that includes two porosity levels is necessary. We present the formulation of the dual structure model and describe its implementation into a coupled fluid flow and geomechanical numerical simulator. We use the Barcelona Basic Model (BBM), which is an elasto-plastic constitutive model for unsaturated soils, to model the macrostructure, and we assume that the strains of the microstructure, which are volumetric and elastic, induce plastic strain to the macrostructure. We test and demonstrate the capabilities of the implemented dual structure model by modeling and reproducing observed behavior in two laboratory tests of expansive clay. As observed in the experiments, the simulations yield non-reversible strain accumulation upon suction cycles and a decreasing swelling capacity with increasing confining stress. Finally, we model, for the first time using a dual structure model, the long-term (100,000 years) performance of a generic high-level nuclear waste repository with waste emplacement in horizontal tunnels backfilled with expansive clay and hosted in a clay rock formation. We compare the thermo-hydro-mechanical results of the 2 3 4 dual structure model with those of the standard single structure BBM. The main difference between the simulation results using the two models is that the dual structure model predicts a time to fully saturate the expansive clay barrier in the order of thousands of years, while the standard single structure BBM yields a time in the order of tens of years. The saturation evolution of the buffer predicted by the dual structure model follows the short-term (up to 10 years) tendency observed in the mock-up test for the FEBEX in situ test, which gives confidence of the performance of the model. These examples show that a dual structure model, like the one presented here, is necessary to properly model the thermo-hydro-mechanical behavior of expansive soils.

A simple formalism is presented to model the behaviour of expansive clays. Two levels of structure are considered. The behaviour of the macrostructure follows the model developed for unsaturated materials by Alonso et al. [Ge ´otechnique 40 (3) (1990) 405-430]. The behaviour of the microstructure is adapted from the work of Gens and Alonso [Can. Geotech. J. 29 (1992) 1013-1032] in order to include the possibility of the micropores being partially saturated. Mechanical coupling between both levels of structure are defined through two functions, one for wetting and the other for drying. They express the change in macrostructural void ratio due to a change in microstructural void ratio, and their value depends on the state of compaction of the macrostructure. The general shape of these curves is discussed on the basis of experimental evidence. Phenomena such as the dependency of strain on stresssuction path, accumulation of expansion strain during suction cycles at low confining stress, accumulation of compression strain during suction cycles at high confining stress, strain fatigue during drying-wetting cycles, macropore invasion by expanded microstructure and development of macroporosity during strong drying can be represented. A mathematical formulation of the model is described and its performance finally assessed by comparison with laboratory tests.

This study investigates the structural performance of interlocking blocks produced in Zambia using different compression methods and cement stabilization levels. A total of 112 blocks (220 × 200 × 110 mm) were manufactured using manual and hydraulic pressing techniques with 8% and 11% cement stabilization. Comprehensive testing included compressive strength evaluation at ambient and elevated temperatures (200°C, 600°C, 1000°C), and water absorption assessment. Results demonstrated superior performance of hydraulically compressed blocks, achieving average compressive strengths of 3.70 N/mm² and 3.32 N/mm² for 11% and 8% cement content respectively, meeting Eurocode Grade A standards for load-bearing applications. Manually compressed blocks exhibited significantly lower strengths (2.09 N/mm² and 2.02 N/mm²), qualifying only for Grade C non-load-bearing applications. Statistical analysis confirmed significant differences between compression methods (p < 0.05). Water absorption exceeded recommended limits across all samples (17.69-20.19% vs. 5% standard), attributed to the soil composition (40% clay/silt, 60% sand). Fire resistance testing revealed initial strength gains at 200°C followed by gradual degradation at higher temperatures. The study establishes hydraulic compression as essential for structural applications while identifying water absorption as a critical area requiring optimization for enhanced durability in Zambian construction.
Keywords: Interlocking blocks; Hydraulic compression; Compressive strength; Water absorption; Cement stabilization; Sustainable construction

This paper discusses the design and construction of the foundation for a bridge approach embankment which consists of back-to back mechanically stabilized earth walls (MSE) constructed within a wetland area. The walls are highest at the bridge abutment with a maximum height of 10 meters. Soil improvement was undertaken to provide suitable foundation for the approach embankment. The soil improvement consisted of installation of vibro concrete columns (VCC) penetrating the soft soil into suitable sandy soil layers in conjunction with a geotextile reinforced sand platform to transfer the embankment fill load to the VCC. This solution constituted the first use of VCC by a US Department of Transportation to support an approach embankment. The design concept of the embankment supporting system is outlined. However, emphasis is given to the behavior of the geotextile component of the system. The performance of the embankment supporting system is assessed based on monitoring data obtained f...

Conventional coupled elastoplastic deformation-flow finite element methods are not suitable for stability problems, since numerical results often become unstable as stresses in the elements arrive at the critical state. An analytical method using the imaginary viscosity method, a standard viscoplasticity computation scheme, is developed to analyse soil behaviour from start to failure. The procedure is validated using the examples of the bearing capacity of a footing on clay and an embankment on soft soil.

This study examines the particle size distribution, workability, and compressive strength of concrete mixes containing laterite soil and fine aggregate. Compressive strength tests conducted at 7, 14, 21, and 28 days revealed that fine aggregate exhibited superior strength development compared to laterite soil. Concrete with fine aggregate achieved compressive strengths of 22.55 N/mm², 23.65 N/mm², 26.80 N/mm², and 30.00 N/mm² at 7, 14, 21, and 28 days respectively. In contrast, laterite soil mixes recorded 17.50 N/mm², 12.45 N/mm², 15.80 N/mm², and 17.65 N/mm² over the same periods, indicating slower and less consistent strength gain. Slump test results showed that fine aggregate mixes were more workable and cohesive than those made with laterite soil. Sieve analysis further revealed that fine aggregate had a well-graded particle size distribution, enhancing compactness and structural stability, whereas laterite soil was coarser and less uniform. Based on the results, fine aggregate is recommended for structural concrete applications requiring high early and long-term strength, while laterite soil is better suited for non-structural or lowload-bearing uses.

This paper reports the results of laboratory study performed on expansive soil reinforced with geofibers and demonstrates that discrete and randomly distributed geofibers are useful in restraining the swelling tendency of expansive soils. Swelling characteristics of remoulded expansive soil specimens reinforced with varying fiber content (f ¼ 0.25% and 0.50%) and aspect ratio (l/b ¼ 15, 30 and 45) were studied. Onedimensional swell-consolidation tests were conducted on oedometer specimens. Reduction in heave and swelling pressure was the maximum at low aspect ratios at both the fiber contents of 0.25% and 0.50%. Finally, the mechanism by which discrete and randomly distributed fibers restrain swelling of expansive soil is explained with the help of soil-fiber interaction.

The use geotextile sand containers (GSCs) as shoreline protection systems, has grown moderately since the first applications in the 1970s. This slow growth can be attributed to two factors; firstly, the lack of understanding of coastal processes and design fundamentals by the larger geosyntheticcommunity in order to provide coastal engineers with suitable solutions, and secondly; there has been very little rigorous scientific wave flume testing with which to analyse the wave stability of geotextile sand containers. The application of geotextile containers in coastal protection works can be traced back to early works carried out in 1970s. The application of these types of structures was somewhat haphazard as very little was understood about the wave stability and durability of the structures. Early wave stability work was carried out and Jacobs (1983) with small containers, however, the testing programs were limited and did not provide sufficient confidence in the product to carry out exhaustive engineering design. As a result, the technology until recently has relied on manufacturers' design suggestions based on monitoring of actual structures. Over the past five years, coastal population pressure, extreme events and concerns over climate change and sea level rise have resulted in more emphasis being placed on shoreline protection systems. Geotextile manufacturers have responded to the challenges put forward by design engineers and intensive research has been carried out in the field. This paper outlines the current "state of the art" in terms of the design and specification of geotextile sand containers (GSC). This paper covers the key issues which will ensure the long term integrity of a geotextile shoreline protection system is maintained, these issues include: Container stability; Detailed analysis of recent large scale wave flume testing which assess filling capacity, size of container, structure slope and scour protection etc.; Container/geotextile durability; Methods and specifications used to limit the effects of the fundamental factors affecting the life span of geotextile containers such as vandal resistance, UV degradation and abrasion resistance etc.

This study investigates the sustainable use of blast furnace slag (BFS), an industrial product from iron-ore industries, and sugarcane bagasse ash (SCBA), an agricultural by-product from sugar industries, as admixtures to improve the geotechnical index and engineering properties of black cotton soil (BCS). A total of sixteen distinct mix proportions were adopted and were organized under three series, including BB (BFS + BCS), SB (SCBA + BCS), and BSB (BFS + SCBA + BCS) series. The effectiveness of BFS, SCBA, and BFS-SCBA in improving the properties of the BCS is evaluated using a series of laboratory tests-consistency limits (CL), free swell index (FSI), compaction characteristics, ultrasonic pulse velocity (UPV), unconfined compressive strength (UCS), and hydraulic conductivity (HC) of BB, SB, and BSB-series. The analysis focussed on establishing these admixtures for novel and sustainable chemical stabilization and hydraulic barrier applications in landfills. The findings showed that CL and FSI monotonically decreased in all series. The compaction characteristics, such as maximum dry unit weight, increased in the BB and BSB series and decreased in the SB series. However, optimum moisture content decreased in the BB and BSB series and increased in the SB series, respectively. The UPV values increase with the increase in the densities of the mixes. The UCS value increases with increased curing intervals, tested at 0, 7, 14 and 28 days. This is attributed to amorphous silica and free-lime present in SCBA and BFS, resulting in pozzolanic reaction and cementitious products that improve the properties of treated soil. Furthermore, the HC values decrease in the BB and BSB series and increase in the SB series. Based on the findings from this study, the use of combined industrial and agricultural by-products proves to be an eco-friendly, sustainable, and productive solution for treating BCS as a novel chemical stabilization and feasibility assessment for hydraulic barriers under engineered landfills.

Soil is the base of any construction, so for any construction activity engineers cannot construct their structure on soil of less strength. It becomes very important to stabilize soil so that it can bear the load of the structure and keep the structure safe and sound. There are various waste materials, and rather than disposing of them, they can be used to improve soil strength like CBR, Tri axial, and UCS. This study investigates and analyze, upon mixing that material what are the change in the properties of soil. Various waste materials like Processed Ewaste, Fly ash, Plastic Strips, Stone dust, Slag, Rise Husk, Bottom ash, Bagasse Ash, Coir fiber, Waste Tyre chips, Waste Glass, Sewage Sludge, Foundry Sand, Ash. These materials are readily available and easy to handle. These materials could be used as an alternative to various stabilizers. It can be used in multiple fields like soil stabilization, concrete production, brick manufacturing, improving soil quality, and manufacturing of cement. On comparing it was concluded that these materials are economically, efficient and eco-friendly compared to traditional methods.

Vertical movements calculated with the new design method for six case study cross sections in three different climatic zones in Texas were compared with the swelling movement predicted by the potential vertical rise (PVR) method, which has been used by the Texas Department of Transportation. Vertical movements included both swelling and shrinking. A review of assumptions that underlie the PVR method shows that two assumptions are unrealistic because they are not based on sound analytical principle and the three others cannot be supported by subsequent findings on actual Texas pavements or on soils of the United States. Pavement treatments were selected to provide acceptable predicted performance at high levels of reliability, and the vertical movements were calculated both at the edges of pavements and beneath the outer wheelpaths. The case studies were based on a variety of traffic levels, site conditions, and sample testing. The pavement treatments included limestabilized and cement-stabilized layers, removal and replacement with inert layers, and vertical and horizontal moisture barriers. The results of the case studies showed that the PVR method overpredicts the swelling movement that can be expected with the new method and does not predict shrinkage movement, which is important because that is an indicator of future longitudinal shrinkage cracking along the pavement edge.

A model was developed to predict pavement roughness caused by both expansive soils and traffic in terms of the serviceability index (SI) and the International Roughness Index (IRI). The model correlates the roughness analysis to the vertical movement estimated from the Texas A&M University suction-based method. The total vertical movement (including both swelling and shrinking) at the edge of pavement sections, the geometry of the pavement, site conditions, traffic, and the level of reliability were used as model parameters. Total movements calculated at the edge of pavement sections were based on a relationship between moisture content and suction, exponential suction envelopes, volume change coefficients, pavement treatments, and roadside conditions. Pavement treatments included vertical and horizontal barriers, inert soil, and lime-stabilized or cement-stabilized layers. The movements in wheelpaths at a distance from the edge of pavement were estimated on the basis of both field observations and the computed results of a transient finite element analysis. Transverse distribution of vertical movements on a pavement cross section was estimated. A relationship between IRI and SI was developed on the basis of surface profile measurements in several pavement study sections. The design equations that were developed for both flexible and rigid pavements include the effects of traffic and expansive soil and permit the selection of the desired level of reliability.

Soil stabilization is crucial for the construction industry in regions with clayey expanding soil. Adding certain materials can enhance the geotechnical properties of the soil. Ground glass powder is studied herein as an additive to clay soil, by applying the Atterberg Limit Test (ALT). The use of ALT can give a basic assessment of the suitability of the soil, which also determines the optimal ratio of the glass material that must be added to the mixture. Laboratory experiments were conducted utilizing the Casagrande apparatus by adding 4%, 5%, and 6% of ground glass to clay soil, and the impact of these percentages on soil characteristics was evaluated. The results exhibited a noticeable change in the mixture limits and plasticity. Increasing the percentage of added glass leads to a decrease in all three Atterberg limits improving soil stability and reducing soil plasticity.

The soil compaction is one of the most common activities of civil construction. It is applicable to construction of fills, dams, roads and embankments. The compacted soils can be subjected to various external and environmental loading after construction. The external loading can arise from superstructure loading, moving traffic and overburden soils. The environmental loading can come from the interaction of surficial soils with the atmosphere in forms such as wetting and drying. Under the combination of these loadings, the compacted soils display complex patterns of behaviour such as swelling, collapse, tensile cracking and swelling pressure development against buried nonyielding bodies. The current approaches for predicting the behaviour of compacted soils during subsequent external and environmental loading are, on one hand, are very complex, and on the other hand, are not entirely satisfactory. The seminar will present a new framework for predicting the behaviour of compacted soils under these loadings, referred to as MPK (Monash-Peradeniya-Kodikara) Framework (Kodikara, 2012). More recent experimental results supporting the framework will also be presented.

Modelling of water flow and associated deformation in unsaturated reactive soils (shrinking/swelling soils) is important in many applications. The current paper presents a method to capture soil swelling deformation during water infiltration using Particle Image Velocimetry (PIV). The model soil material used is a commercially available bentonite. A swelling chamber was setup to determine the water content profile and extent of soil swelling. The test was run for 61 days, and during this time period, the soil underwent on average across its width swelling of about 26% of the height of the soil column. PIV analysis was able to determine the amount of swelling that occurred within the entire face of the soil box that was used for observations. The swelling was most apparent in the top layers with strains in most cases over 100%.

Several foundation techniques have been put to use in order to stabilize expansive soil and counteract various problems posed by expansive soils. Expansive soils can cause heavy economic losses and pose a source of risk to the population. Expansive soils can be stabilized by reducing its swell-shrink properties and improving its load bearing capacity by addition of by-products and use of geotextiles. Stabilization can be done by using lime, fly-ash which have been put to use. This paper presents a new technique in which fly-ash column (FAC) is reinforced with lime and encased by non-woven geo-textile (Polyester) in black cotton soil (BC). Preliminary tests and California Bearing Ratio test were performed on BC soil in which FAC reinforced with lime encased with non-woven geo-textile (NWG) is introduced. Strength carrying capacity of BC soil was improved and swell-shrink properties were considerably reduced when BC soil was introduced with FAC reinforced with NWG. Experimental labora...

The cost associated with damage due to swelling soils is more than double the cost associated with damage from floods, hurricanes, tornadoes, and earthquakes. This paper illustrates the numerical modeling of block molded expanded polystyrene, (EPS) geofoam, used as a compressible inchtsion between expansive soils and a retaining structure. In several hypothetical cases, the reduction on the transmitted lateral pressures on a retaining structure is determined with different thieknesses of EPS. The reduction on the transmitted lateral pressures are compared with the reduction of granular backfill.

Cyclic drying and wetting phenomena of the expansive clayey soils cause the progressive settlements which could affect principally the foundations of buildings, the drainage channels and the buffers in radioactive waste disposals. In order to better understand the coupling between these hydraulic cycles and the mechanical behaviour of the swelling soils, this article presents an experimental study performed on two different expansive soils (molded and natural) using oedometer tests by imposing suction variations with the osmotic technique. Several successive swelling and shrinking cycles were applied under different constant vertical net stresses. During the suction cycles, the compacted samples showed cumulative shrinkage strains. On the other hand, the natural samples presented cumulative swelling strains. At the end of the suction cycles, the volumetric strains reached an equilibrium stage which indicates an elastic behaviour of the samples. We can relate these elastic behaviours to the soil fabric and especially to the microstructural content of soil.

This study investigates whether low-cost pozzolanic materials such as rice husk ash, groundnut shell ash can improvement soil used in the study that are classified as Lowplasticity clays (cl) and activity of it equal to 1.05 as a replacement for traditional, costly additives. the percentage are used be 4%, 6%, 8%, and 10% of weight soil for each additive. chemical properties were studied for rice husk ash, groundnut shell ash, and cement Portland such as CaO, SiO2, Al2O3, Fe2O3, MgO, K2O, and Na2O. Also, preand post-mixture soil was tested for Atterberg's Limit, Activity, Shrinkage Limit, Clay value, Proctor Standard Compaction, and Unconfined Compressive Strength. Untreated soil samples were compared to treated ones. Adding 8% cement OPC, 10% groundnut shell ash, and 10% rice husk ash enhanced soil cohesiveness from 21 to 57.5, 52, and 45 kPa, respectively, also the optimal soil moisture content dropped from 15% to 8%, 10.5%, and 10% for mixes. Increased mixer percentages lead to reduced maximum dry unit weight and optimized water content. Based on these observations aims to develop effective solutions for treatment expensive soil in engineering and construction projects.

A multi-mechanism generalisation of Sloan's integration scheme for elasto-plastic laws has been developed in order to implement a double structure model for expansive clays into a FE code. The constitutive model is built on a conceptual approach for unsaturated expansive soils in which the fundamental characteristic is the explicit consideration of the two pore levels often present in expansive clays. The distinction between macro and microstructure provides the opportunity to take into account the dominant phenomena that affect the behaviour of each structural level and the main interactions between them. The model is formulated using concepts of classical and generalised plasticity theories. The integration scheme proposed can deal with the two plastic mechanisms defined in the model and can incorporate the effects of strains, suction and temperature in the stress integration process. A large scale heating test is analysed to check the capabilities of the implemented model to simulate an actual problem involving complex thermo-hydro-mechanical stress paths. The performance of the model has been very satisfactory and the proposed integration scheme has proved to be robust and efficient in solving a highly non-linear coupled problem.

Understanding of Construction and Demolition Waste (CDW) is very essential in the thriving economy and its management is nowadays a global priority. In this scenario, awareness of CDW management is need of the hour. Before implementing rules, first, there is a need to understand the CDW generation. Present study investigates the detailed review of the current practices and challenges that influences the construction and demolition waste management in India and around world. In addition, study reviews the recent research in managing CDW.Some of the potentially significant field of application such as reusability of waste soil from railway construction sites as soil amendments, highway embankment application, conversion of lignocellulose based CDW to bioethanol, traffic orientation sensor production etc.

This paper investigates the performance of flexible pavement on expansive soil subgrade using gravel/flyash as subbase course with waste tyre rubber as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the gravel subbase shows better performance as compared to flyash subbase with different percentages of waste tyre rubber as reinforcing material. Cyclic load tests are also carried out in the laboratory by placing a circular metal plate on the model flexible pavements. It was observed that the maximum load carrying capacity associated with less value of rebound deflection is obtained for gravel reinforced subbase compared to flyash reinforced subbase.

During construction of road and railway projects, expansive soils may be encountered. Their use as construction material for embankments presents difficulties, due to their tendency to swell or shrink. Traditional solutions include mixing soil with cement or quicklime, or to import materials from other locations. As an alternative to these solutions, the present paper proposes a less expensive and more sustainable solution, consisting in mixing the natural expansive soil with rubber particles obtained from scrap tyres. Especially, the "Facies Tap" (a typical soil of southeastern Spain) is studied in this paper. This soil, which is mainly a white argillaceous marlstone, is mixed with six different amounts of rubber content (2.5, 5, 10, 15, 20 and 25% in terms of weight) and submitted to several geotechnical tests, including compaction, free swelling, unidimensional consolidation, direct shear testing and undrained shear compression. The addition of rubber particles to the soil up to a 15% makes it lighter and less prone to swelling, while compressibility remains similar to the natural soil and the drained shear strength slightly increases. Based on experimental results, the optimum rubber content mixed with the soil to prevent its swelling is established at around 3%.

The aim of this study is to investigate the causes of cracks and plaster spills observed in some walls and floor slabs of a light building, to determine whether these damages are caused by the soil, to present solution suggestions and preventive and/or remedial measures that can be taken for the damages caused by the soil, and to prepare the improvement project by evaluating the data obtained as a result of field and office studies for this purpose. For this purpose, soil investigation studies were carried out to reveal the geological and geotechnical properties of the soil on which the light building erected, and to determine whether the cracks and deformations seen in the building are caused by the soil. It was determined that the deep cracks observed in the walls and floors on the south and west sides of the light building were caused by the swelling pressures of the soil.

Keywords: light building, building damage, swelling clay, expansive soil, Ankara clay

This is the era of reformation and soil is considered the basic foundation for every civil structure. Now a day due to short availability of land, we would have to erect structures on weaker soil too. This is where soil stabilization comes into play. An effective soil stabilization technique should be able to bear the loads without failure. ‘RBI Grade 81” an effective chemical admixture is used for strengthening and simultaneously enhancing the properties of weaker soil. In this study ‘RBI Grade 81’ is incorporated with soil to enhance the strength parameters on account of bearing capacity and compaction. The consequences of ‘RBI Grade 81’ on the soil characteristics were explored by conducting ‘standard compaction tests’ & ‘CBR test’. The tests were performed as per Indian Standard specifications.

The relationship between suction and water content gives crucial information about a soil. Small projects like economic housing do not warrant the time and cost of determining the full soil water suction curve. A considerable range of soil suctions can easily be achieved within a reasonably short time by using small samples, simple suction control and a high precision balance. It appears that in this way it may be possible to estimate heave potential and variability of soil properties at reasonable cost in an acceptable time. Variability assessment appears to be of great value and may offer significant potential for improving the reliability of foundation design on shrink/swell soils.

Construction of light structures in arid climates generally results in an increase in water content of the subsoil profile due primarily to irrigation and a reduction of evapo-transpiration. Water introduced by irrigation at the surface migrates downward and increases the water content at depth as it advances. Although the subsurface is wetted significantly, the soil above the wetting front may not become saturated. If the wetting front encounters an aquatard, a perched water condition may develop and the soils above the aquatardmay become saturated. Determination of a final water content profile for design of foundations on expansive soils is an important design parameter. In the absence of other data, it is conservative to assume that the entire profile is saturated. Alternately, modeling of water migration in the vadose zone can be performed to determine water content profiles for various site conditions. The results of this rigorous analysis can be used to determine a final water content profile for use in optimizing the design of foundations. However, this rigorous analysis is not always economical for small projects. Thus, a simplified procedure is presented that can be used to hand calculate final unsaturated water content profiles for design of foundations on expansive soils. The results of the water migration modeling and hand calculation methods are presented and the applicability of these methods is discussed. The resulting foundation design based on the final water content profiles determined from these two methods, as well as the assumption of full saturation, is presented and discussed.

The consolidation-swell test is commonly used for measuring expansion potential and predicting heave for expansive soils in the Front Range area of Colorado, USA. In performing the test and analyzing the results, it is important to consider the specific nature of the dense highly consolidated claystones and clayshales of this area. Such materials have also been observed to exist throughout the Western United States and other parts of the world. This paper presents a discussion of many factors that are considered in the ASTM Standard Test Method but which are inadequately addressed for these materials and are not always observed by commercial testing laboratories. 2 COMMENTARIES 2.1 Swell pressure A typical oedometer used in Colorado, USA is shown in Figure 1. This is termed a consolidometer in The Standard. This apparatus is commonly used to measure the percent swell, S%, and the swell pressure of a soil. The Standard defines swell pressure as "the minimum stress required to prevent swelling".

The calculation of heave from oedometer test results utilizes a constitutive parameter termed the heave index, C H. This parameter defines the relationship between the amount of swell, εs%, that a soil will exhibit as a function of the vertical stress acting on the soil as it becomes wetted. The value of the heave in-dex is determined from the percent swell at a particular inundation stress and the swelling pressure determined in a constant volume oedometer test. It is convenient, therefore, to have a relationship between the swelling pressure as determined by constant volume and consolidation-swell oedometer tests in order that only one oedometer test is required to determine CH. Such a relationship was developed on the basis of observed soil behavior in oedometer tests. An equation is presented that requires determination of a parameter “m” for a particular soil. Analysis of data from a data bank of approximately 40 test results on a number of differentexpansive soils has shown that for those soils the value of m varied within a relatively narrow range. Sample calculations showed that within the range of most of the observed values of m the predicted heave varied within a small range. Thus, if a representative value of m can be determined for a particular soil, heave can be predicted with reasonable accuracy.

Slope failures in embankments constructed in expansive soils are often induced by rainfall infiltration during wet seasons or after a heavy rainfall event. Field investigations regarding the effect of rainfall infiltration on slope instability for expansive soil embankments indicate that shrinkage cracks developed during the drying and wetting cycles play an important role in slope instability. The excessive amount of infiltration through the shrinkage cracks decreases the matric suction of the expansive soil, and hence, results in a reduction of the shear strength of the soil accompanied with soil expansion, or heave. Furthermore, the modulus of elasticity of the soil decreases as water content increases and the soil heaves. The influence of these factors on the slope stability of expansive soil embankments is reviewed and discussed in the paper. Numerical modeling using the finite element computer programs SEEP/W and SIGMA/W was conducted to evaluate the volume change of an expansive soil embankment slope due to changes in suction arising from infiltration. Longterm stability of the expansive soil embankment slope was conducted using the computer program SLOPE/W. The expansive soil slope was also analyzed with a proposed remediation scheme to evaluate the effect of the remediation on long-term stability. The results of the numerical modeling for the slope with remediation were compared to those obtained for the slope without remediation. Furthermore, heaving of the expansive soil is accompanied by a reduction in the shear strength of the soil. Therefore, analysis of heave using the oedometer method was discussed in the paper. The results of the heave prediction using the oedometer method were compared to those obtained from the numerical modeling method. Reasons for the differences in amounts of predicted heave using both methods are discussed in the paper.

Nelson et al. (2015) presented design principles for foundations on expansive soils. The design principles consider free-field heave throughout the design life of a structure as the basis for foundation design. The design principles also consider water migration in the vadose zone, and the time required for subsoil wetting over the design life of the structure. This paper presents a method to validate th foundation design method presented in Nelson et al. (2015). The validation was performed using detailed long-term data obtained on a building constructed on expansive soils at the Denver International Airport, Denver, Colorado, USA. Water migration in the vadose zone and heave of floor slabs and drilled pier foundations were monitored over the time period from 2000 to 2016 and extended to a 25 year period (1991-2016) beginning at the end of construction. Water content profiles were modeled using VADOSE/W software, and heave of slabs and piers were computed using the design method presented in Nelson et al. (2015). The depth of wetting and changes in water content were used to compute heave according to the design method. Calculated heave was compared to the survey data. It was shown that the design method was capable of predicting heave to within 30 percent of the measured heave over a 25-year period.

This is the era of reformation and soil is considered the basic foundation for every civil structure. Now a day due to short availability of land, we would have to erect structures on weaker soil too. This is where soil stabilization comes into play. An effective soil stabilization technique should be able to bear the loads without failure. ‘RBI Grade 81” an effective chemical admixture is used for strengthening and simultaneously enhancing the properties of weaker soil. In this study ‘RBI Grade 81’ is incorporated with soil to enhance the strength parameters on account of bearing capacity and compaction. The consequences of ‘RBI Grade 81’ on the soil characteristics were explored by conducting ‘standard compaction tests’ & ‘CBR test’. The tests were performed as per Indian Standard specifications.

The research aims to improve some of the physical and hydro-physical properties of some Vertisols in the southern region (part of the eastern Houran Plateau) in Sweda Governorate at the south of Syria. Using different quantities of volcanic ash, soil samples were collected from the Al-Thahallah village from a depth of (0-30) cm, The experiment was designed according to the complete random design with one factor that represents the ash quantity (1.25, 2.5, 5) %, with three replicates for each treatment in addition to the control treatment a0. The experiment was carried out within the plastic pots during agricultural season 2018/2019, in which the wheat of the Sham variety 3 were cultivated as a cover plant. The results showed that the addition of volcanic ash at the quantity of 5% led to a significant increase in the infiltration rate by (328.60) %,%, where the filtration rate increased from 0.42 cm/hr-1 to 1.80 cm.h-1, as well as for each of the air porosity by (89) % and the volume of infiltrate water by (40) %, compared with the control. The above-mentioned addition also resulted in a decrease in both dry bulk density, total soil porosity and volumetric swelling coefficient by (18.60, 5.80, 314) % Respectively, compared to the control. The addition also contributed to the reduce in the weighted moisture content when saturation and the field capacity, at the level of significance of 5%. The research recommends adding volcanic ash to the soil at a quantity of 5%, and adding enhancements with volcanic ash at various levels such as organic waste.

In the present study, sand and expanded polystyrene (EPS) geofoam were evaluated as potential stabilizers in improving the swelling behaviour of bentonite. A comprehensive laboratory experimental programme was conducted on bentonite with a high swelling potential. Five dosage levels of sand and five different thickness of EPS geofoam were investigated in two stages of the experiments. In the first stage of testing, the effect of sand on the swelling pressure of bentonite was investigated by two series of experiments. In the first series of experiments, bentonite at optimum water content was mixed with sand in proportions of 20, 40, 60 and 80% by weight. In the second series of experiments, the same percentages of sand were used as in the first series of experiments but the sand and bentonite were not mixed together. The sand was placed on the sample of bentonite which was then compacted at optimum water content. In the second stage of testing, the effect of EPS geofoam on the swelli...

This study was carried out to review different types of available innovative construction materials. It was found that advancement in nanotechnology, use of mineral admixture, glass and plastic, biological materials, wood and other construction materials have contributed significantly to the growth of discovery and production of innovative construction materials. The implementation of some innovative construction materials, meets the requirements for sustainability, durability, reliability, safety, cost reduction, increasing quality, better mechanical and physical characteristics, flexibility in extreme conditions and locations, simple assembly and environmentally friendly. Construction materials used to carry out project consumed about 40% of the entire cost of the project in the construction industry. The success stories were recorded in the area of turning industrial and agricultural wastes to wealth. This reviewed paper will enrich the database for innovative materials entering ...

In our society today most of the aggregates that were used for concrete work were usually abandoned on site for some times with minimum of 6 month or more due to different factors as it may apply. Some which might be due to lack of fund by the client and tussles. This abandonment led to a situation where construction materials are piled onsite over a range of periods of time. These materials are left dormant and exposed to harsh weathering conditions before utilization. This study accessed the effects of aggregates dormancy on its properties quality when use. The study was carried out in three calendar years (2015, 2016 and 2017) to check weathering activities on dormant aggregates. Experimental procedures such as Sieve analysis, silt content, specific gravity, water absorption and compressive strength test were carried out on these aggregates to determine its quality of performance on the product (building). Based on the duration of aggregate on site, it was observed that the strength of concrete produced from the aggregates increased and the aggregates were coarser when exposed to the weather. The study concluded that due to slight changes in compressive strength over the years, dormant aggregate has no negative effect on concrete strength and quality of structural components but it is advised that any procured aggregates meant for construction should be totally free from clay and silt contents. This will enhance the concrete strength and also accelerate its setting time.

In this study, the drying-induced microstructure evolution of compacted silt with different salinities is investigated using mercury intrusion porosimetry and environmental scanning electron microscope. The pore size distribution (PSD) of specimens compacted near optimum (w = 17%) exhibited bimodal characteristics. Upon drying (w = 8%), the PSD changed to a trimodal pattern with the appearance of a new nano-pore population. This suggested the development of nano-fissures, which could occur in the clay fraction and at the interface between clay particles and silt/sand grains due to the clay shrinkage. With further drying (w = 3%), the nano-pores disappeared and the PSD recovered to bimodal characteristics, suggesting that the nano-fissures created were enlarged until they became micro-fissures. The salinity seemed to decrease the frequency of the drying-induced micro-pores due to the enhanced mechanical strength of salted soil by the soil aggregation resulting from the compression of...

Stabilization techniques have often been used globally to enhance properties of weak subgrade materials for flexible pavement construction. This study assessed the blend of calcium carbide waste (CCW) and calcined clay (CC) to serve as an effective stabilizer of Subgrade material (S) sourced from a section along Ota-Idiroko road. Subgrade material was initially modified with CCW in different percentage replacements by weight (0, 4, 8, 12, 16 and 20%) and the resulting blends were subjected to Atterberg’s limits test to determine the blend with optimum plasticity index reduction which would be tagged optimum subgrade lime blend (OSLB). The blend of S + 8% CCW was tagged OSLB because it exhibited optimum plasticity index reduction. The OSLB was thereafter blended by weight with CC in the following percentage replacements 3, 6, 9, 12, 15 and 18% in order to activate the pozzolanic potentials of CC for strength enhancement. The resulting blends were subjected to Atterberg’s limits, Comp...

The heave of expansive soil information is a fundamental part of the preparation of a foundation design to accommodate the anticipated volume change and consequences associated with the foundation movement over the design life of the structure. The one-dimensional oedometer is the most widely accepted method to identify and evaluate the amount of swell that may occur. Although the oedometer is used extensively for evaluating the amount of heave, the procedures used are quite varied, and few of the methods have been validated experimentally. An objective of this research study is to briefly explain common practices and existing heave prediction by oedometer methods and then, to validate by experimental laboratory heave tests using soil sample from Ngawi. The two prediction methods provided results that represent low and upper bound predictions of the actual soil heave movement in the laboratory. The difference between the prediction with heave measurement is about 29,50% and 45,02%, ...

The version presented here may differ from the published version. If citing, you are advised to consult the published version for pagination, volume/issue and date of publication Effect of glycerol on the behavior of an expansive soil during wetting and drying cycles The behavior of an expansive soil with different flooding fluid, i.e. distilled water and solution of glycerol with different percentages of glycerol (10, 20, 30 and 40%) was studied through a number of cyclic wetting and drying tests. Experimental tests were conducted on compacted samples of the expansive soil in a modified oedometer with different flooding fluids under a surcharge pressure of 10 kPa. The vertical and radial deformations of the samples were determined during different stages of wetting and drying. The results showed that during cycles of wetting and drying, the deformation of the soil decreased with increasing the number of cycles for all flooding fluids. The magnitude of deformation for samples flooded with solution of glycerol is less than distilled water and this reduction is a function of glycerol concentration. The equilibrium condition of samples with glycerol solution is reached in fewer cycles than distilled water and the number of cycles to reach equilibrium was a function of percent of glycerol. The results also indicated that the swelling-shrinking deformation was nearly the same when the equilibrium condition was attained. Comparison of the results showed that by increasing the percent of glycerol, these curves were contracted. Furthermore, the paths of wetting and drying converged to an Sshaped curve at equilibrium condition.