Mohamed Abd Elrahman

• Ph.D
• Mansoura University

This study explores the use of ten different fine materials to partially substitute cement, aiming to reduce greenhouse gas emissions from cement production. The materials include two types of fly ash (coarse and fine), blast furnace slag, silica fume (SF), three grades of limestone powder (coarse, medium, fine), and three grades of quartz powder....

This study examines the impact of replacing up to 5 vol% of Portland cement (PC) with both pristine Bi2O3/Gd2O3 (BG) and silica-coated BG particles. Two different types of silica coatings, each with varying synthesis methods, were applied to coat the BG structures, and their impact on the fresh, hardened, microstructure and radiation-shielding perf...

This research focuses on development of infra-lightweight foamed concrete with very low density. The first step is to manufacture stable preformed foam with optimizing the applied air and water pressure as well as the foaming agent dosage. Then, an appropriate mixing procedure of infra-lightweight concrete is developed. In the experimental plan, 8...

In this study, ultra-lightweight concrete with an oven-dry density of 800 kg/m ³ was produced using expanded glass as the lightweight aggregate. Polypropylene fibers of different sizes were incorporated into the specimens to examine their effects on the material properties, such as drying shrinkage and flexural strength. The target dry density was...

Alkali‐activated waste glass (AA‐WG) has received much attention because to its high mechanical properties achieved with low energy demand. However, AA‐WG exhibits low stability, including volume expansion, porosity increment, and a reduction in compressive strength. Enhancing the stability of AA‐WG could improve its commercial viability and expand...

The utilization of gypsum waste (GyW) as an additive for alkali-activated materials has already been addressed. However, using GyW as a partial replacement for aluminosilicate during the alkali-activation process is not sufficient for the full disposal of such waste. Accordingly, this communication focused on full transforming GyW from fertilizers...

This study uses an eco-efficient approach for sustainable phosphogypsum (PG) waste disposal by creating a mesoporous AFt binder. The results reveal that mixing PG waste with a synthetic sodium aluminate can induce the formation of the AFt phase through a cationic exchange reaction at room temperature. The morphology, expansive property, mesopore vo...

This study presents a new approach towards the production of sol-gel silica-coated Bi2O3/Gd2O3 cement additives towards the improvement of early mechanical performance and radiation attenuation. Two types of silica coatings, which varied in synthesis method and morphology, were used to coat Bi2O3/Gd2O3 structures and evaluated as a cement filler in...

According to the literature, the engineering properties of alkali-activated slag (AAS) generally decrease as temperatures rise up to 1200 ◦C. Although the addition of certain amorphous aluminosilicate additives can increase the residual strength of AAS, it still exhibits lower performance compared to samples cured at ambient temperature. Hence, the...

Structural lightweight concrete is preferred over traditional concrete due to its ability to reduce the dead load, minimize the size of load-bearing structural members, and provide more economical solutions for foundation deteriorations. This research sheds light on sustainable lightweight concrete using waste crushed clay bricks (CCB) as a lightwe...

UHPC is a modern cement-based composite with exceptional mechanical characterizations and durability, while also being a high-cost and unsustainable composite. Therefore, ultra-high performance geopolymer concrete (UHPGC) was developed to achieve similar mechanical performance with more economic and ecological benefits. In this study, the engineeri...

The use of alternative and locally available materials is encouraged in the construction industry to improve its sustainability. Desert regions with shortages in freshwater and river sand as fine aggregates in concrete have to search for alternative materials such as seawater, dune sand, and waste glass powder to produce lightweight concretes. The...

Globally, several million tons of various wastes are produced each year, and these quantities are projected to rise. Environmental issues arise from the landfilling or burning of many of these wastes. These wastes can gradually be used as replacement construction materials to reduce their harmful impacts on the environment. In this context, geopoly...

The main objective of this study is to develop 3D printed heavyweight concrete (3DPHWC) to produce elements with a dry density of up to 3500 kg/m3 by replacing natural aggregate (SA) with magnetite aggregate (MA) up to 100%. A comprehensive systematic study was conducted to thoroughly assess mixtures' mechanical properties, physical proficiency, fr...

Many research articles and reviews have recognized alkali-activated materials (AAMs) as eco-friendly alternative binders to ordinary Portland cement (OPC) due to their economic andenvironmental advantages. However, few literature surveys reported the physical, mechanical and microstructural changes that occur after the exposure of AAMs to elevated...

Worldwide, vast amounts of waste are produced every year and most waste is sent directly to landfills or burnt, which has severe and harmful impacts on the environment. Recycling waste materials is considered the most visible solution to protect the environment. Using scraps in concrete production is a proper method for getting rid of wastes, impro...

The current work studies the applicability of using a statistical model supported by response surface methodology (RSM) in the formulation and optimization of sustainable UHPC mixtures incorporating industrial waste materials. The effects of the three main variable components of UHPC, ultra-fine fly ash (UFFA), metakaolin (MK), and steel fibre cont...

Sensible thermal energy storage using concrete as a storage medium is a promising technology that helps minimize energy in power plant. The purpose of this study is to evaluate the potential benefts of metakaolin (MK) as a partial substitute for fy ash-based geopolymer for heat resistance. As a partial substitute (5 and 20 wt.%) for fy ash (FA),...

The present work aimed at accelerating the early hydration rate of sodium sulfate (Na2SO4) activated slag via nano magnesia (nM). Slag was activated by two Na2SO4 concentrations equivalent to 1 and 3 wt% Na2O (SS1 and SS3, respectively). The results demonstrated that the addition of nM accelerated the hydration rate and raised the pH of the medium,...

This research evaluates the effect of high temperatures up to 800 °C on the compressive strength and microstructure of the developed ultra-high performance geopolymer concrete (UHPGC) containing waste glass (WG) and ceramic (WC). Fine aggregate was partially substituted with WG and WC in the range of 7.5-22.5% by vol. Samples were heated in the ran...

This study reports a potential approach for the valorization of glass waste (GW) that is mainly composed of amorphous silica to prepare lightweight foamed glass (FG). The preparation of FG was achieved by mixing sodium hydroxide with GW powder followed by sintering at a temperature of 800 °C. As-synthesized FG was characterized and applied as an ef...

Recycling waste materials instead of using traditional construction materials in civil infrastructure and buildings is a significant step toward reducing greenhouse gas emissions and the consumption of natural resources. The scope of this research is to identify the properties of sustainable concrete where waste materials such as rubber tires, crus...

This work examines the influence of iron oxide nanoparticles (Fe3O4 NPs) on neutron and gamma-ray radiation shielding characteristics of Portland cement paste. Experimental evaluations were supplemented with theoretical studies using NXCom program. Portland cement pastes with 5, 10, 15, 20, and 30 wt% of nanomagnetite cement replacement were produc...

Concrete sulfate attack is of great interest as it represents one of the main reasons of concrete deterioration and poor durability for concrete structures. In this research, the effect of different cement types on concrete sulfate resistance was investigated. This included three concrete classes, namely, low strength concrete, medium strength conc...

This paper investigates the effect of recycled waste glass powder (RWGP) and particle packing optimization on the performance of UHPC. RWGP was obtained by crushing and grinding waste glass and reaching a fineness close to that of cement to study its influence on UHPC performance. UHPC mixtures were designed by optimizing the binder system based on...

Large amounts of cement and natural aggregates are used annually to produce concrete, and the high energy consumption required for the production of these materials is considered to be a major environmental concern globally. This study investigates the effect of marine wastes, such as cockle shells and waste fishing nets, on the microstructural cha...

This study investigates the efficiency of ensemble machine learning for predicting the lightweight-aggregate concrete (LWC) characteristics. A stacking ensemble (STEN) approach was proposed to estimate the dry density (DD) and 28 days compressive strength (Fc-28) of LWC using two meta-models called random forest regressor (RFR) and extra tree regre...

The role of nanozinc source (nanohydrozincite: nHZ; nanozinc oxide: nZO) on the performance of alkali-activated slag (AAS) was explored for the first time in the present work. The results showed that nHZ with different contents (0.5, 1.0, and 1.5 wt%) retards the early hydration rate of AAS, whereas nZO showed the lowest retardation effect. Zn(OH)2...

Utilization of waste crushed bricks (WCB), which are obtained from brick factories and demolition waste as coarse and fine aggregate for preparing concrete, is an adequate strategy to reuse them and save natural resources to achieve environmental sustainability. This study investigates the possibility of developing eco-friendly structural lightweig...

Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high cement replacement ratios. This has also some a...

The present paper focuses on synthesizing an alkali-activated binder, in which magnesium carbonate (MC) was the only precursor. MC was individually activated with sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and sodium aluminate (NaAlO2). Increasing Na2O content (as NaOH) up to 10 wt% enhanced the compressive strength slightly. At constant Na...

One of the advantages of geopolymer technology is the ability to recycle a variety of wastes. In this paper, waste glass was incorporated into ultra-high performance geopolymer concrete (UHPGC). Recycled waste glass replaced fine sand in various ratios in UHPGC. Several mixtures were prepared by replacing natural sand with 0%, 7.5%, 15%, and 22.5%...

In the present work, different MgCl2 dosages were admixed with lead glass sludge (LGS) to evaluate their effects on the performance of the produced LGS-foam at different elevated temperatures. The results revealed that adding MgCl2 caused a negative impact on the bloating process, including porosity and volume expansion reduction, as well as bulk d...

The impact of barium silicate nanoparticle (nBS) on the performance and phase composition of blast-furnace slag activated with low sodium oxide content (2.33 wt.%) was explored for the first time in the present work. Adding nBS enhanced the workability, accelerated setting times, and improved the mechanical properties of alkali-activated slag (AAS)...

This study presents the comparison of microstructural and durability characteristics of 3D printed concrete (3DPC) depending on its production method (printing or casting). Printed samples with different numbers of layers, as well as a cast specimen with an identical mix composition, were produced and compared, with their microstructural pore and s...

The role of Ni and Cr wastewater on the mitigation of the deterioration rate of alkali-activated slag (AAS), caused by biogenic sulfuric acid produced by a sulfur oxidizing fungus (SOF: Aspergillums Niger), is evaluated. The cationic leaching rate, the fungal biomass and the pH of a medium are the compositional parameters which determine the abilit...

Solid waste recycling is a cost-effective strategy to protect the environment, preserve natural resources, and minimize raw material usage. This study aims to assess the influence of waste materials (WM) on the performance of eco-friendly ultra-high-performance geopolymer concrete (UHPGC). A total of 10 specimens were incorporated with crushed glas...

Self-compacting concrete (SCC) is a category of cement-based materials that need a high amount of binder to achieve the required characteristics. Various fine materials can be used to replace Portland cement (PC) and reduce the carbon footprint associated with cement manufacturing. In this research, the synergistic effect of metakaolin (MK) and gro...

In this study, microstructural characterization of various foamed concrete specimens was conducted using multi-scale X-ray microcomputed tomography (micro-CT). Foamed concrete specimens with cement only and fine sand or supplementary cementing materials (SCMs), such as fly ash and silica fumes, were prepared, which can improve the mechanical proper...

To date, nondestructive tests (NDT) applications and advances in detecting the dispersion and defections of the nano concrete (NC) materials fields are very limited. The current paper provides a review of the dispersion efficiency of nanomaterials in cement-based materials and how NDT can be efficiently used in detecting and visualizing the defecti...

The utilization of waste crushed clay brick (CB) in concrete reduces its harmful impacts on the environment as it can be found in many places around the world. This research studies the possibility of using clay brick powder (CBP) as a filler material to produce lightweight concrete as it has been exposed to high temperatures during manufacturing o...

The huge amount of waste crushed clay bricks (CCB) causes serious environmental problems worldwide. To deal with this issue and preserve natural resources, CCB can be recycled and reused in the concrete industry. This paper investigated the influence of CCB as substitution of cement and aggregates on the physical, mechanical, and microstructural pr...

Hybrid cement (HC) can be defined as alkali activated-blended-Portland cement (PC). It is prepared by the addition of an alkaline solution to high-volume aluminosilicate-blended-PC. Although this cement exhibits higher mechanical performance compared to conventional blended one (aluminosilicate–PC blend), it represents lower commercial viability be...

This study presents a comparison of the effects of micro-Bi2O3 and nano-Bi2O3 powders on the mechanical, microstructural and gamma / neutron shielding properties of Portland cement pastes. Cement pastes with various ratios of cement (up to 30 wt-%) replaced with Bi2O3 micro and nanoparticles were prepared. Consistency, compressive strength, water a...

This paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m ³ , in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as c...

This study presents the experimental results of an investigation on the effects of nanosilica (NS) on the material characteristics of printable mortars used for additive manufacturing. Printable cement mortars based on Ordinary Portland Cement, limestone filler and silica sand were modified with different dosages of nanosilica (from 2% to 6% by wei...

This study presents a comparative analysis of the effects of lightweight aggregate concrete (LWAC) and foamed concrete (FC), with dry densities of 500, 750 and 1000 kg/m³, on the thermal performance of a typical multi-family (residential) building. Typical two-layer walls consisting of an essential layer (LWAC or FC), with an insulating layer of fo...

Lightweight aggregate concrete (LWAC) has relatively larger porosity than conventional concrete, mainly due to the incorporation of porous lightweight aggregates. The types of used lightweight aggregates are critical in determining the physical properties of LWAC, and it is therefore important to examine their effects on the durable characteristics...

This investigation studies the effects of hot water and hot air curing on the strength development, transport properties, and freeze-thaw resistance of mortars incorporating low-heat blast furnace slag cement and nanosilica (NS). Mortar samples were prepared and stored in ambient conditions for 24 h. After demolding, mortar samples were subjected t...

This work is aimed at characterizing the effects of nanosilica (NS) on the properties of lightweight aggregate concretes with different densities. Lightweight aggregate concrete (LWAC) and ultra-lightweight aggregate concrete (ULWAC) with targeted oven-dry densities of 850 kg/m³ and 450 kg/m³, respectively, were produced. The mixtures were modified...

Implementing sustainability can enhance quality of our life and thus granting us a healthy life and promote economic, social, and environmental circumstances. The appropriate use of building materials helps in reducing negative environmental impact and life-cycle cost of buildings. This paper proposes a set of parameters that affects selecting sust...

It is well known that the chemical precipitation is regarded as an effective approach for the preparation of nano-materials. Nevertheless, it represented several drawbacks, including high energy demand, high cost, and high toxicity. This work investigated the eco-sustainable application of plant-derived urease enzyme (PDUE)-urea mixture for synthes...

This investigation presents the influence of various types of nanoparticles on the performance of ultra high performance concrete (UHPC). Three nanoparticles from waste materials include nano-crushed glass, nano-metakaolin, nano-rice husk ash were prepared using the milling technique. In addition, nano-silica prepared using chemical method at the l...

Mechanical behaviors of foamed concrete, which is a cellular lightweight binder with entrained air voids, are evaluated using the phase field fracture model in a finite element framework. A methodology to identify the micro-scale material properties/parameters of the foamed concrete to predict their macro-scale mechanical behaviors is presented. Mu...

The performance of vacuum insulation panels (VIPs) is strongly affected by several factors, such as panel thickness, design, quality of vacuum, and material type. In particular, the core materials inside VIPs significantly influence their overall performance. Despite their superior insulation performance, VIPs are limited in their widespread use as...

Microstructural characteristics and properties of foamed concrete, a cellular lightweight cement paste with entrained air voids, are investigated. The complex 3D microstructures of the foamed concrete with different densities are obtained by micro-CT imaging and binarized as two-phase (pore/solid) materials by image processing. The mechanical respo...

This study aims to more accurately investigate the pore size distribution of air voids in cement-based materials. For this purpose, micro-computed tomography (micro-CT) images were used to describe the inner structure of target materials, without damaging them. Together with the data obtained and the imaging techniques used, the pore structures of...

Foamed concrete is highly porous, and the pores inside the material improve the insulation performance. However, the material strength decreases with increasing pores (porosity). To enhance the mechanical properties of the material without reducing porosity, the solid matrix of foamed concrete can be adjusted. For this purpose, several foamed cemen...

Improving the thermal insulation properties of cement-based materials is the key to reducing energy loss and consumption in buildings. Lightweight cement-based composites can be used efficiently for this purpose, as a structural material with load bearing ability or as a non-structural one for thermal insulation. In this research, lightweight cemen...

This study presents the results of an experimental investigation of the effects of nanosilica (NS) on the strength development, transport properties, thermal conductivity, air-void, and pore characteristics of lightweight aggregate concrete (LWAC), with an oven-dry density <1000 kg/m³. Four types of concrete mixtures, containing 0 wt.%, 1 wt.%, 2 w...

The rapid increase in waste quantities, as well as the depletion of the natural resources in the near future are some of the major concern worldwide. In response to these problems, as well as to the growing demand for concrete in the construction field, the focus has been directed towards the production of artificial aggregates, as an alternative t...

Lightweight concrete is a special type of concrete with low density and advanced insulation, mainly produced using lightweight aggregates or a cellular matrix. Concrete material made of lightweight aggregates is called lightweight aggregate concrete, while material made from a cellular matrix is generally called foamed concrete because of the pores...

In this study, core-shell structured lightweight aggregates (CSA) were produced through the cold bonding method, by encapsulating an expanded perlite particle (as a core structure) within a shell matrix composed of cement, fly ash and expanded perlite powder. The effect of different curing regimes on the mechanical and microstructural properties of...

In this contribution, the effect of waste magnetite powder (MP), obtained from a rock crushing process, as an additive to cement pastes exposed to elevated temperature and gamma-ray radiation, is evaluated. Cement pastes with different magnetite powder to cement ratios, up to 50% by mass, and exposed to temperatures of 200 °C, 300 °C, 450 °C and 60...

Featured Application This work can be useful in the development of stable ultra-lightweight foamed concrete mixtures with improved mechanical strength and decreased drying shrinkage and without deterioration in thermal insulation properties. Abstract Increasing interest is nowadays being paid to improving the thermal insulation of buildings in ord...

This contribution investigates the effects of seawater and colloidal silica (NS) in the amounts of 1, 3 and 5 wt%, respectively, on the hydration, strength development and microstructural properties of Portland cement pastes. The data reveal that seawater has an accelerating effect on cement hydration and thus a significant contribution to early st...

Lightweight concrete is a building material used for better insulation and lower energy consumption. The material properties of lightweight concrete, such as compressive strength and thermal conductivity, are strongly affected by the characteristics of its aggregate, binder, and other concrete additions. This study aims to investigate the effects o...

This study aims to investigate the effects of carbon nanotubes and carbon nanotube-silica core-shell structures, on the behaviour of cement pastes exposed to high temperature (300, 450 and 600 °C). Pristine multi-walled carbon nanotubes (MWCNTs) were coated with a solid nanosilica (NS) shell, to form a core-shell nanostructure (MWCNT/NS). The cemen...

The density of cold-bonded lightweight aggregates is significantly higher than that of sintered lightweight aggregates. Since the sintering technique consumes an enormous amount of energy and emits a huge amount of pollutants, the implementation of a cold-bonded method, in manufacturing low-density lightweight aggregates, is very important from an...

Exposure to elevated temperatures has detrimental effects on the properties of cementitious composites, leading to irreversible changes, up to total failure. Various methods have been used to suppress the deterioration of concrete under elevated temperature conditions. Recently, nanomaterials have been introduced as admixtures, which decrease the t...

Expanded polystyrene (EPS) can be used as an aggregate for producing environmental friendly lightweight concrete. A set of EPS spheres with different sizes and arrangements were used to produce lightweight concrete with density lower than 1700 kg/m³. The arrangements of the EPS aggregates were numerically designed, and a series of lightweight concr...

Due to the high number of discarded end-of-life tyres around the world every year, the use of rubber waste in concrete has been researched for some years in normal and high strength concrete. Rubcrete is a type of concrete which is similar to conventional concrete, but uses scrap tyre rubber as a partial substitution for mineral aggregates. Lightwe...

Lightweight aggregate concrete is a material which has much lower density than normal concrete and many advantages, including advanced insulation performance due to its highly porous or cellular characteristics. Several types of lightweight aggregates have been used to produce lightweight aggregate concrete, and the characteristics of such lightwei...

Insulating concrete is a material designed to reduce heat conduction with pores/insulations, and these pores strongly affect the material characteristics. In general, the insulation effect is directly proportion to the pore volume, while the material strength decreases as the porosity increases. To overcome this contrary, anisotropic insulations wi...

Recently, the recycling of waste glass has become a worldwide issue in the reduction of waste and energy consumption. Waste glass can be utilized in construction materials, and understanding its effects on material properties is crucial in developing advanced materials. In this study, recycled crushed and expanded glasses are used as lightweight ag...