Mahfooz Soomro

Followers

Following

Public Views

Interests

Uploads

Papers by Mahfooz Soomro

Construction and Demolition Waste

International Encyclopedia of Housing and Home, 2012

Production of cement and its environmental impact

Recycled Concrete

Industrial and agro-waste materials for use in recycled concrete

Elsevier eBooks, 2023

Quality improvement of recycled aggregate

Elsevier eBooks, 2023

Production of cement and its environmental impact

Elsevier eBooks, 2023

Hybrid methods to improve microstructure of recycled concrete and brick aggregate for high-grade concrete production

Magazine of Concrete Research

Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvem... more Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvements to recycled concrete and brick aggregate; however, the applications have their limitations. Further, recycled brick aggregate cannot be effectively carbon-conditioned with conventional methods as it contains only trace amounts of reactive materials. It is therefore a necessity to use hybrid methods involving dual technologies combining carbon-conditioning and chemical permeation for its improvement. This paper is focused on developing a novel hybrid method for improving the microstructural properties of recycled concrete aggregate and recycled brick aggregate for concrete usage. This study conducts particle density, water absorption and crushing value tests to measure the physical improvements achieved with the novel hybrid method, and utilises a variety of chemicals and a reaction chamber for carbon-conditioning for aggregate treatment. The study evinces that both the recycled conc...

A Step towards Sustainable Concrete with Substitution of Plastic Waste in Concrete: Overview on Mechanical, Durability and Microstructure Analysis

Crystals

Plastics have become an essential part of our daily lives, and global plastic production has incr... more Plastics have become an essential part of our daily lives, and global plastic production has increased dramatically in the past 50 years. This has significantly increased the amount of plastic garbage produced. Researchers have recently been interested in using trash and recyclable plastics in concrete as an ecologically acceptable building material. A large number of publications have been published that describe the behavior of concrete, containing waste and recovered plastic com ponents. However, information is scattered, and no one knows how plastic trash behaves as concrete materials. This research examines the use of plastic waste (PW) as aggregate or fiber in cement mortar and concrete manufacturing. The article reviewed the three most significant features of concrete: fresh properties, mechanical strength, and durability. PW and cement connections were also studied using microstructure analysis (scan electronic microscopy). The results showed that PW, as a fiber, enhanced me...

Download

Grindability and Behaviour of Phases in Cement Hydration

Journal of Engineering and Applied Sciences , University of Engineering and Technology, Peshawar, 1989

Clinker is formed in the Cement Kiln when the raw meal is fused at temperatures of 1450-1550 ᴼC. ... more Clinker is formed in the Cement Kiln when the raw meal is fused at temperatures of 1450-1550 ᴼC. This fused material or clinker has to he quickly air cooled (quenched) to enhance its tri-calcium silicate formation which is the basic strength giver of the Ordinary Portland Cement. Clinker is then ground, together with some percentage of gypsum in a grinding mill, to a required surface area (Blaine). The effect of grinding on the characteristics of Ordinary Portland Cement has been emphasised in this article in order to give a hint to the quality control personnels of our cement plants that this final and important factor of grinding can put deleterious effect on the performance of the cement they produce, irrespective of how much controlled parameters they maintain at raw material section and in kiln.

Study of the Hydration of Ordinary Portland Cement Using Thermal Analysing Techniques

Ordinary Portland Cement produced by one of the S.C.C.P. units, is the subject of hydration studi... more Ordinary Portland Cement produced by one of the S.C.C.P. units, is the subject of hydration studies, using thermal methods such as TG and DTA. Hydration is measured in terms of hydration product formation and the amount of chemically bound water and free calcium hydroxide contained in the hydration products for different curing times. i in ' t > It is noticed that the critical degree of hydration at which strength starts developing, is a function of hydrating time and theoretically corresponds to the termination of acceleration period, when tri-calcium and di-calcium silicates in the cement have hydated, to produce enough hydration products to intermesh and initiate an early strength. The experimental data is interpreted in terms of strength development as a function of hydration.

Study of the Voidage Structure of the Packed Bed

Journal of Engineering and Applied Sciences , University of Engineering and Technology, Peshawar, 1987

An experimental study have been carried out to formulate the voidage structure of the packed bed.... more An experimental study have been carried out to formulate the voidage structure of the packed bed. Polystyrene spheres packed in PVC pipe were cut in slices in the radial plane, photographs were taken and frcm these photographs voidage at different radial positions were computed. The method adopted was to compute the 'line-voidage * rather than area voidage or volume voidage.

Rice Husk Cement a Potential Source for Rural Development

Journal of Engineering and Applied Sciences , University of Engineering and Technology, Peshawar, 1992

Portland Cement is the World’s most widely used building material. Its production not only involv... more Portland Cement is the World’s most widely used building material. Its production not only involves a large investment of capital, but at the same time, it is also ranked as one of the high energy consuming industries in the world. Hence scientists are continuously on the look-out for materials which can be used as substitute for conventional materials or which would possess such properties as would enable their use for construction instead of Portland Cement. In the last decade or so, significant advances have been made in the use of rice-husk for the production of cement. Its potential economic advantages for developing countries that have large quantities of rice-husk readily available, virtually free of cost, are enormous. At Cement Research and Development Institute (CRDI), instead of blending rice-husk ash (RHA) produced in a reducing atmosphere and at controlled temperatures, a new method involving very low or no technical knowledge, was adopted. Rice husk and lime slurry, in...

Methods to Mitigate the Negative Effects on Durability of Recycled Aggregate Concrete

Hydro Dynamics of Packed Bed Reactors

Journal of Engineering and Applied Sciences , University of Engineering and Technology, Peshawar, 1985

This is an interpretative review article which does not attempt to cover the entire literature bu... more This is an interpretative review article which does not attempt to cover the entire literature but attempt have been made to discuss the important topics from an extensive array of literature data. The first half of this paper takes into account the effect of solid packings on the flow pattern of the fluid passing through a packed bed reactor. Fluid flow characteristics, velocity profiles in the bed, within the packing voids and in the wall region. Since radial dispersion tends to create plug flow conditions, hence only axial dispersion, its mechanisms, effects of system variables on axial dispersion and wall and end effects have been discussed in the second half.

Quality improvement of recycled concrete aggregate by removal of residual mortar: A comprehensive review of approaches adopted

Construction and Building Materials, 2021

Abstract With the goal of achieving sustainable development, numerous research studies have been ... more Abstract With the goal of achieving sustainable development, numerous research studies have been conducted aimed at reducing construction and demolition waste for improving sustainability and environment and reducing greenhouse-gas emissions. Recycled concrete aggregate due to its residual adhered mortar has low specific gravity and high water absorption. Both of these impediments contribute in the increase of permeability and shrinkage, decrease in compressive strength and hence concrete quality produced from recycled concrete aggregate. Consequently, it is essential to improve the recycled concrete aggregate quality such that their properties become comparable with those of virgin aggregate. In order to improve the recycled concrete aggregate quality, researchers have adopted two main pathways: (1) removal of adhered mortar from aggregate grains and utilisation of the separated mortar, and (2) fortification of residual mortar to make it stronger, less permeable and hydrophobic. The present study focuses on the first pathway and aims to comprehensively review huge variety of treatment techniques available in the literature, which can be applied to enhance the recycled concrete aggregate quality, by removing maximum amount of the attached mortar, thereby increasing its density, reducing its water absorption, and subsequently producing high quality aggregate. In addition, the processes which can effectively utilise the removed mortar have been reviewed. The combination of both, separation of mortar from aggregate grains and its complete utilisation make these treatments economically viable. These treatments which are based on the published literature, have been individually analysed based on their applicability and efficacy.

An Overview of Freeze and Thaw Cycles Affecting the Durability of Recycled Aggregate Concrete

Proceedings of the 25th International Symposium on Advancement of Construction Management and Real Estate, 2021

Deformation and permeability of recycled aggregate concrete - A comprehensive review

Journal of Building Engineering, 2021

Abstract Properties of recycled aggregate concrete (RAC) were found to be dependent on the source... more Abstract Properties of recycled aggregate concrete (RAC) were found to be dependent on the source, its composition and consistent quality of demolished concrete waste. Many studies have shown that using recycled aggregate (RA) in concrete suffers from strength and durability problems caused mainly due to relatively porous residual mortar adhered on the surface of aggregate grains resulting in high water absorption and increase in permeability and shrinkage. Also, the weaker interfacial transition zone (ITZ) of about 20–50 μm thickness in-between mortar and aggregate particles plays important role in reducing the bond strength between RA and fresh concrete, hence the physical and mechanical properties of RAC are usually inferior than virgin aggregate concrete (VAC). This review paper focuses on two main characteristics of RAC: (a) deformation (shrinkage and creep); and (b) permeability (carbonation, chloride ingress and air and water penetration) which have a direct effect on the durability of RAC and recommends methods for the mitigation of their adverse effects. The effects of mineral admixtures, water to cement (w/c) ratio, and high-range (HR) superplasticisers on the durability properties of RAC have been reviewed. This research showed that a very meager number of authors (only 12 publications) have focused on both the essential durability characteristics i.e., deformation and permeability together; therefore, we feel a need to present a review focusing on both of these essential properties.

Methods to improve microstructural properties of recycled concrete aggregate: A critical review

Construction and Building Materials, 2021

h i g h l i g h t s Critical review for methods, and technologies for recycled aggregate. Various... more h i g h l i g h t s Critical review for methods, and technologies for recycled aggregate. Various methods are reviewed, including self-healing, bacterial, etc. Existing studies to improve the properties of the recycled aggregate, are limited. Density improvement techniques of chemicals and reactions are limited.

Download

Alkali-Activated Mortars with Recycled Fines and Hemp as a Sand

Materials, 2021

Nowadays, effective and eco-friendly ways of using waste materials that could replace natural res... more Nowadays, effective and eco-friendly ways of using waste materials that could replace natural resources (for example, sand) in the production of concrete composites are highly sought. The article presents the results of research on geopolymer composites produced from two types of waste materials—hemp and fine fractions recovered from recycled cement concrete, which were both used as a replacement for standard sand. A total of two research experiments were conducted. In the first experiment, geopolymer mortars were made using the standard sand, which was substituted with recycled fines, from 0% to 30% by weight. In the second study, geopolymers containing organic filler were designed, where the variables were (i) the amount of hemp and the percent of sand by volume (0%, 2.5%, and 5%) and(ii) the amount of hydrated lime and the percent of fly ash (by weight) (0%, 2%, and 4%) that were prepared. In both cases, the basic properties of the prepared composites were determined, including t...

Download

Evaluation of Carbon Nanotube Incorporation in Cementitious Composite Materials

Materials, 2019

Over the last decades, new materials with outstanding performance have been introduced in the con... more Over the last decades, new materials with outstanding performance have been introduced in the construction industry. Considering these new technologies, it is worth mentioning that nanotechnology has revolutionized various areas of engineering. In the area of civil engineering and construction, cement is used for various purposes and the search to improve its performance has been receiving growing interest within the scientific community. The objective of this research was to evaluate the behavior of cement mortar produced by the addition of multi-walled carbon nanotubes (MWCNTs) in different concentrations by comparing their physical and mechanical properties with the properties of the nanotube-free composite. Motivated by the lack of consensus in the literature concerning to the optimal dosage of CNTs in cementitious matrices, three different carbon nanotube ratios, 0.20, 0.40 and 0.60 wt % Portland cement, were investigated with the aim of evaluating the mechanical properties. De...

Download

A review of recycled aggregate in concrete applications (2000–2017)

Construction and Building Materials, 2018

The paper reviews the production and utilisation of recycled aggregate in concrete. Critically an... more The paper reviews the production and utilisation of recycled aggregate in concrete. Critically analysed the globally published data on recycled aggregate standards. This review may help to alleviate the concerns of consumers. This paper can encourage and further promote the use of recycled aggregate.

Download

Mahfooz Soomro

Uploads

Papers by Mahfooz Soomro

Log In