Papers by Muhammed Basheer
Developments in intelligent sensing of concrete structures
Materials
Establishing the carbonation profile is of great significance to the prediction of the service li... more Establishing the carbonation profile is of great significance to the prediction of the service life of reinforced concrete structures. In our previous work, Raman spectroscopy was shown to be an efficient tool for characterizing calcium carbonate (CaCO3) polymorphs and their profile in plain Portland cement (PC) matrices. However, as supplementary cementitious materials (SCMs), particularly fly ash (FA) and ground granulated blast furnace slag (GGBS), are widely used in concrete, establishing the carbonation profile without considering the possible effects of these SCMs could be of little significance to the real world. This paper, thus, investigated the effects of FA and GGBS on the working capacity and reliability of Raman spectroscopy for establishing the carbonation profile in PC blends containing SCMs. The thermogravimetry (TG) analysis was also conducted to verify the results from Raman spectroscopy. The results show that Raman spectroscopy demonstrated a good capacity for dif...
Linking climate change, moisture dynamics and salt movement within natural building sandstones: implications for salt transport by diffusion
Future climate change scenarios for much of the UK suggest that the key stone decay controlsof te... more Future climate change scenarios for much of the UK suggest that the key stone decay controlsof temperature and moisture input will change. Seasonality in precipitation is projected toincrease, essentially meaning that winters are due to become wetter, while summers are likelyto become drier. For building stones, this translates into longer 'time-of-wetness' periodsduring winter that are linked not simply to surface wetness, but specifically to 'deep wetting'.Data from sandstone test walls in the wet west of Northern Ireland demonstrate the build up ofinternal moisture related to cumulative rainfall. During initial moisture penetration, salts canbe re-distributed in solution, but once blocks become saturated it is likely that further redistributionwill occur through ion diffusion. This paper seeks to make links between climatechange, stone moisture dynamics, and ion diffusion, experimenting to assess how quicklydiffusion takes place in building sandstones and the pote...
Role of aggregate grading and size on the durability of ordinary Portland Cement concrete
Monitoring of corrosion in situ in structural reinforcement bars using a 'wrapped fibre optic sensor network
Despite numerous reported cases of failure of concrete structures the durability of concrete is s... more Despite numerous reported cases of failure of concrete structures the durability of concrete is still compromised due to lack of a clear strategy for ensuring its performance in the exposure environment. This is someway addressed in EN 206-1: 2000, by specifying 6 different exposure classes with 23 different sub-classes in total. However, the approach to ensure durability in these service environments is still prescriptive or "deemed-to-satisfy" manner. Therefore, a performance-based strategy to specify concrete and a set of performance tests to assess its performance in the service environment are essential so that reliable prediction of its service life could be made. Such an approach is likely to contribute to improving the sustainability of concrete infrastructure, by minimising premature replacement of structures and allocating resources in a timely and planned manner. This strategy is introduced in this paper and suggestions for making further progress are made.
Guidelines for selecting concrete mixes based on performance testing and long-term performance
It is reported that the diffusion of chlorides in Alkali-activated slag (AAS) concretes is lower ... more It is reported that the diffusion of chlorides in Alkali-activated slag (AAS) concretes is lower than that in Portland cement (PC) counterparts and is comparable to concretes containing high volumes of supplementary cementitious materials. This is considered to be due to its dense calcium silicate hydrate structure and relatively better chloride binding capacity due to its high alumina content. However, a critical review of the literature indicated that both the resistance to chloride ingress and chloride-induced corrosion of steel in AAS concretes are not found uniformly in all publications. Further, less is known about the effect of mix proportions, including binder content, water-binder ratio, role of activator, etc. on the rate of chloride transport through AAS concretes. As a consequence, there is conflicting information on the ability of AAS concretes to delay both the onset and the rate of corrosion of embedded steel in such concretes. Therefore, a thorough investigation was ...
Quality control and performance assessment methods for concrete structures
Role of performance indicators in assessing the state-of-health of concrete infrastructure
It is widely recognised that durability of concrete depends on its transport properties, viz. abs... more It is widely recognised that durability of concrete depends on its transport properties, viz. absorption, diffusion and permeability. As concrete cover provides the first line of defence against the ingress of many deleterious substances into the concrete, a measure of its transport properties is vital in assessing its long term performance in the given exposure condition. In new structures the rate of ingress of the deleterious substances could be monitored using array of electrical sensors which are embedded in the cover concrete. For structures which are currently in service, two in situ permeability apparatuses, viz. Autoclam Permeability System (for measuring gas/water permeability and water absorption) and Permit Ion Migration Test (for determining the ionic diffusion) could be employed. These instruments can be mounted on the concrete surface for carrying out the tests. Typical results are presented for these two novel testing systems to illustrate their usefulness for the co...
Controlled permeability formwork
Construction repair, 1992
An in situ permeability test method that does not require assumptions for the uni-directional flo... more An in situ permeability test method that does not require assumptions for the uni-directional flow has been developed to determine the air permeability coefficient of the near surface concrete. The proposed method involves applying a constant pressure head to a surface mounted ring and measuring steady state air flow rates. The analysis is based on modification of the flow net theory, which needs a calibration factor accounting for the influence of specimen and ring geometries. Effects of test area, width of seal, depth and width of test specimen were investigated using numerical simulation of air flow. The results indicated that the value of the calibration is very sensitive to change of testing area which needs to be corrected for a specimen with a depth less than 50 mm. The experimental studies suggest the duration to achieve the steady state depends on the quality of the concrete tested and the applied pressure. The results indicated that the test method is capable of identifyin...
In-situ testing of near-surface concrete - The foundation for service life prediction
Assessing the possibility of alumina conversion in concrete containing neutralised bauxite refinery residue
Special issue - Concrete research in Ireland - Guest editorial
Construction and Building Materials, 2005
Fifteen years of research on the Assessment of durability of concrete using In Situ air permeability and sorptivity measurements
In-situ assessment of corrosion induced damage of the Dickson bridge deck
This paper presents developments in the use of an embedded, multi-electrode conductivity sensor t... more This paper presents developments in the use of an embedded, multi-electrode conductivity sensor to study the response of the concrete cover-zone to environmental action. The sensor enables an evaluation of the temporal and spatial variation of electrical conductivity thereby allowing an integrated assessment of the cover-zone. Conductivity sensors were embedded within concrete samples to study the cover-zone response to cyclic wetting and drying under laboratory conditions. This work was extended to include the use of remote interrogation methods to study samples placed at a marine exposure site and preliminary results are presented.
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Papers by Muhammed Basheer