Article
Construction & Building Technology
Da -Wang Zhang, Xue-Mei Sun, Ke-Fei Zhao, Hui Li
Summary: This study investigates the thermal properties and phase transformations of alkali-activated fly-ash materials (FA-AAMs) after high-temperature treatment. The results show that the residual compressive strength of the samples significantly increases after treatment. A high Na/Si ratio of 0.5 is found to be optimal for the formation of N-A-S-H gel. However, with increasing temperature, the N-A-S-H gel gradually transforms into a crystalline phase, leading to the destruction of the sample's microstructure.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Construction & Building Technology
Ahmed S. Ouda, Mahmoud Gharieb
Summary: By incorporating ceramic tile waste into pozzocrete-fly ash-based geopolymer, the properties of the material can be enhanced; a 10% inclusion ratio significantly improves the compressive strength as well as the resistance to high temperatures and seawater erosion.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Polymer Science
Osama Ahmed Mohamed, Rania Al Khattab
Summary: This study evaluates the properties of mortars using alkali-activated GGBS and fly ash binders, including sorptivity, setting time, resistance to sulfuric acid, and compressive strength. The experimental results show that these mortars exhibit good water absorption, sulfuric acid resistance, and compressive strength. The best compressive strength is achieved with a binder consisting of 75%GGBS + 25% fly ash.
Article
Construction & Building Technology
Artith Wongpaun, Weerachart Tangchirapat, Teewara Suwan, Mizi Fan
Summary: This study investigates the factors influencing compressive strength and expansion due to alkali-silica reaction in environmentally friendly alkaline-activated materials (AAMs). The findings show that higher concentrations of NaOH solution, heat curing conditions, and finer fly ash particles contribute to increased compressive strength. The presence of calcium minerals enhances the strength of hardened products but also induces later-stage expansion. Furthermore, finely milled fly ash significantly reduces alkali-silica reaction expansion in AAMs.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Engineering, Civil
Adhikesavan Muthadhi, Balasundar Suganya
Summary: The research findings suggest that the alkaline solution to fly ash ratio has a minimal impact on the compressive strength of concrete, whereas a sodium hydroxide solution concentration below 6 M significantly reduces the compressive strength of geopolymer concrete.
IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF CIVIL ENGINEERING
(2022)
Article
Construction & Building Technology
Guangyan Li, Hongbo Tan, Junjie Zhang, Xiufeng Deng, Xiaohai Liu, Zhongtao Luo
Summary: The study systematically investigated the strength development of NC-activated slag-FA blends at ambient temperature, characterized the hydration products and pore structure through experiments, and the results showed that the NC-activated blends exhibited excellent mechanical properties, suitable for engineering applications.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Multidisciplinary Sciences
Joseph O. Ukpata, Desmond E. Ewa, Joseph U. Liwhuliwhe, George Uwadiegwu Alaneme, Koyonor E. Obeten
Summary: This study explored the impact of elevated temperatures on the residual structural properties of concrete made with non-conventional fine aggregates. It found that the use of laterite as a replacement for fine aggregates can improve the density, sorptivity, and strength of concrete. The study also recommended using 25% and 50% laterite replacement for producing different grades of concrete.
SCIENTIFIC REPORTS
(2023)
Review
Polymer Science
Osama A. A. Mohamed
Summary: Reductions of green gas emissions and the reuse/recycling of industrial byproducts are crucial in mitigating the environmental impact of construction. This critical review focuses on the effect of key parameters on the compressive strength development of concrete or mortar using alkali-activated ground granulated blast furnace slag (GBS) and fly ash as binders. It also examines the impact of exposure and sample age on concrete strength development in acidic media.
Article
Geochemistry & Geophysics
Jiangping Zhao, Yachao Wang
Summary: This study investigates the effect of binary composite activators on the microstructure of fly-ash-based geopolymers through 24 experiments. The results show that the Na2SiO3 & BULL;9H(2)O + KOH activator exhibits the highest mechanical strength due to the synergy activation between Na2SiO3 and K+. Furthermore, the addition of silica fume facilitates the formation of amorphous silicates and increases the pore volume. This research provides an efficient and cost-effective fabrication method for fly-ash-based geopolymer and contributes to the development of solid waste recycling techniques.
Article
Engineering, Environmental
Kristina M. Zierold, John Myers, Guy N. Brock, Clara G. Sears, Lonnie L. Sears, Charlie H. Zhang
Summary: Children living near coal ash storage facilities were found to have elevated levels of neurotoxic metal(loid)s in their nail samples, with high correlations among these metals. Principal component analysis revealed the co-loading of iron, aluminum, and silicon from fly ash, indicating potential exposure to fly ash. Geospatial analyses partially validated the hypothesis that proximity to power plants was associated with higher concentrations of fly ash metal(loid)s in children's nails.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Green & Sustainable Science & Technology
Junjie Zhang, Hongbo Tan, Ming Bao, Xiaohai Liu, Zhongtao Luo, Penggang Wang
Summary: Na2SO4 (NS)-activated slag as an alkali-activated binder showed slower strength development but lower CO2 emissions potential compared to NaOH and water glass. By using ultra-fine slag and fly ash (FA), the compressive strength was improved while reducing CO2 emissions. The study indicated a promising low carbon alkali-activated binder.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Polymer Science
Chan-Yi Lin, Tai-An Chen
Summary: This study measured the compressive strength and shrinkage properties of fly ash-based alkali-activated materials (AAM) using different activators. The results showed that similar compressive strength can be achieved by adjusting the alkali-equivalent content and GGBFs replace percentage, regardless of the type of fly ash used. However, the shrinkage performance varied significantly depending on the type of fly ash.
Article
Construction & Building Technology
Prinya Chindaprasirt, Thammanun Boonbamrung, Apivich Poolsong, Wunchock Kroehong
Summary: This study investigated the mechanisms of polypropylene fiber-reinforced alkali-activated high calcium fly ash paste exposed to high temperatures. The results showed that adding 0.5% PP to the mixture resulted in the best improvement in compressive strength, while a slightly higher PP content at 1.0% was optimal for flexural strength. As the temperature increased, the pore structure of AHFP changed accordingly.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2021)
Article
Engineering, Civil
Sarah Fernando, Chamila Gunasekara, David W. Law, M. C. M. Nasvi, Sujeeva Setunge, Ranjith Dissanayake, M. G. M. U. Ismail
Summary: This study explored the use of rice husk ash as a precursor material for alkali-activated binders, finding that replacing fly ash with 10% and 20% RHA resulted in decreases of approximately 14% and 43% in compressive strength. The higher specific surface area and unburnt carbon content in RHA were identified as key factors affecting the lower compressive strength obtained. Additionally, the addition of RHA increased the reactive silica in the gel matrix, leading to a negative impact on compressive strength.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2021)
Article
Engineering, Civil
Muhammad Sohail Jameel, Ali Raza, Mohamed Hechmi El Ouni, Yasser Alashker
Summary: The aim of this study was to improve the mechanical properties of polypropylene fiber-reinforced concrete at elevated temperatures by adding activated and inactivated fly ash. The compressive strength of activated fly ash concrete was 52% and 29.8% higher than inactivated fly ash concrete at 7-days and 28-days, respectively. The use of fly ash enhanced the concrete's strength at elevated temperatures.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Youssef A. Mosleh
Summary: This study investigates the deterioration effect of the marine environment on building materials and compares the effects of different treatment conditions on alkali-activated slag pastes. The results show that the tidal zone and seawater have the most significant damage on the specimens, while water curing has the best improvement on compressive strength.
ACI MATERIALS JOURNAL
(2022)
Article
Construction & Building Technology
Alaa M. Rashad
Summary: The effect of different additives on the carbonation behavior of slag activated with Na2SO4 was investigated. The results showed that the carbonation resistance of slag can be increased by using certain additives.
ACI MATERIALS JOURNAL
(2022)
Article
Construction & Building Technology
Mahmoud Gharieb, Alaa M. Rashad
Summary: This study investigated the possibility of using carbonation lime residue (CCR) as an additive for alkali-activated slag (AAS) cement and found that CCR can serve as a substitute for AAS cement. The inclusion of an appropriate amount of CCR improved the flowability, setting time, compressive strength, microstructure, and durability of AAS cement.
ACI MATERIALS JOURNAL
(2022)
Article
Environmental Sciences
Alaa M. Rashad, Ghada M. F. Essa, Hamdy A. Abdel-Gawwad
Summary: This study investigated the possibility of incorporating recycled glass powder with slag to produce new binder materials. The results showed that the addition of glass powder affected the water absorption and compressive strength of the materials, and had different effects on compressive strength at different temperatures.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Construction & Building Technology
Alaa M. Rashad, Yun Bai
Summary: This paper analyzed and compared the properties of sodium sulfate-activated ground-granulated blast-furnace slag (slag) pastes under carbonation attack with uncarbonated specimens. The results showed that increasing slag fineness has a positive effect on carbonation resistance, while increasing Na2SO4 concentration has a more significant impact. By combining fine slag with high Na2SO4 concentration, the specimens showed excellent resistance to carbonation attack even after 12 weeks.
ACI MATERIALS JOURNAL
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Sayieda R. Zeedan
Summary: In this study, the authors investigated the effect of elevated temperatures on metakaolin geopolymers and explained the inconsistent results in previous studies. Different concentrations of sodium silicate and ratios of silica fume were used to affect the Si/Al and Na/Si molar ratios. The results showed that the addition of silica fume improved flowability and the effect on compressive strength depended on activator concentration.
ACI MATERIALS JOURNAL
(2023)
Article
Construction & Building Technology
Alaa M. M. Rashad, Osama M. M. Haraz, Ayman Elboushi, Wafaa M. M. Morsi
Summary: A first attempt was made to compare the electrical properties of pastes and mortars prepared from alkali-activated materials and Portland cement. The study examined electrical conduction, dielectric constant, dielectric permittivity, and loss tangent factor. The results showed that fly ash-based geopolymer and Portland cement specimens had similar electrical properties. Metakaolin and slag-based geopolymer specimens also had similar electrical properties but with lower conductivity than the other two types. The study also confirmed the similarity in electrical properties between pastes and mortars.
PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-CONSTRUCTION MATERIALS
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Ashraf K. Eessaa, Mervat H. Khalil, O. A. Mohamed
Summary: For the first time, the possibility of adding nano-zirconium (NZ) into alkali-activated slag (AAS) cement as a modifier against seawater attack was studied in this article. Different ratios of NZ were added into the neat AAS cement, and their effects on workability and compressive strength were measured. The results showed that the incorporation of 1% and 3% NZ had a positive effect on compressive strength before and after exposure to different media, while the incorporation of 5% had a negative effect.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Hana Mohamed, Mervat H. Khalil, H. H. Hammed, A. A. El-Gamal
Summary: This study is the first attempt to investigate the effect of micro-sized lead oxide (mPbO) on the properties of alkali-activated slag (AAS) mortars. Different ratios of mPbO were added to the AAS mortar specimens, and the workability, mechanical strength development, transport properties, and accelerated aging resistance were analyzed. The results showed that the addition of mPbO improved the flowability, mechanical strength, and resistance to accelerated aging, with 7.5% mPbO being the optimal ratio. Higher ratios of mPbO did not provide additional improvements and had adverse effects. The transport properties and aging resistance were improved with 2.5-7.5% mPbO, but slightly worsened with 10% mPbO. The microstructure was improved with suitable ratios of mPbO.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Mohamed Ezzat, Abdeen M. El Nagar, M. H. El-Nashar
Summary: Choosing the right type of cement is crucial to limit deterioration in buildings exposed to marine environments. By partially replacing fly ash with limestone powder, the compressive strength of the cement can be enhanced and the degradation caused by seawater and tidal zones can be reduced.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
M. A. Masoud, A. M. El-Khayatt, K. A. Mahmoud, Alaa M. Rashad, M. G. Shahien, Bottros R. Bakhit, A. M. Zayed
Summary: In this study, the hazardous chrysotile was used as an aggregate in radiation shielding concrete for the first time. The addition of boric acid was found to enhance the neutron shielding properties of the chrysotile concrete, although it had detrimental effects on the mechanical and microstructural properties. Computational and experimental results were in good agreement, confirming the suitability of chrysotile as an aggregate in radiation shielding concrete.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Mahmoud Gharieb
Summary: This study evaluated the effect of one year of outdoor natural weathering on the properties of alkali-activated fly ash mortars. The results showed that natural weathering had a negative effect on the compressive strength of the specimens, but this effect could be mitigated by adding silica fume and sodium tripolyphosphate.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Youssef A. Mosleh, Mahmoud Gharieb, Alaa M. Rashad
Summary: The effect of different concentrations of sodium tripolyphosphate (STPP) and sodium hexametaphosphate (SHMP) on the properties of alkali-activated slag/fly ash concrete was investigated. The results showed that both STPP and SHMP can improve workability and compressive strength, with 4% being the optimum concentration. The incorporation of each type of polyphosphate can reduce water absorption and total porosity, and refine the microstructure.
ACI MATERIALS JOURNAL
(2023)
Article
Construction & Building Technology
Alaa M. Rashad, Youssef A. Mosleh, Mahmoud Gharieb
Summary: Despite being abundant in the earth's crust, feldspars have limited applications in alkali-activated materials. This study investigates the effect of different ratios of potassium feldspar on the properties of alkali-activated slag concrete. The results show that feldspar has a positive effect on workability, with increasing ratio leading to increased workability. Incorporating 10% feldspar improves compressive strength, splitting tensile strength, water absorption, total porosity, and microstructure, while higher ratios have a negative effect.
ACI MATERIALS JOURNAL
(2023)
Review
Construction & Building Technology
Alaa M. Rashad
Summary: Calcium oxide (CaO) can be used to improve the properties of alkali-activated materials (AAMs), with its effectiveness depending on the ratio, curing conditions, activator type, and precursor type. Studies have shown that the inclusion of CaO in AAMs reduces workability and setting time, but can increase compressive strength and improve durability.
INTERNATIONAL JOURNAL OF CONCRETE STRUCTURES AND MATERIALS
(2023)
Article
Construction & Building Technology
Qi Jiang, Wei Liu, Shaopeng Wu, Xuanwen Gou
Summary: This study analyzes the erosion mechanisms of NaCl solution on asphalt concrete and finds that NaCl solution softens asphalt and promotes the intrusion of crystalline salt into it. Salt crystallization alters the surface roughness of aggregates, resulting in a decrease in skid resistance but an improvement in compressive strength. Additionally, the concentration of NaCl solution initially has no significant impact on the mechanical performance of asphalt concrete, but its domination gradually increases with the intensification of cyclic effects.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Lili Kan, Lan-qing Dai, Ning Kong, Bin Peng, Fei Wang
Summary: This paper investigates the effect of freezing and thawing cycles on the tensile behavior of cracked ultra-high performance concrete (UHPC). The results show that long-term freezing and thawing action deteriorates the cracking strength, tensile strength, tensile strain, and strain energy of cracked UHPC. On the other hand, the action of water generally favors the development of tensile properties of UHPC. The crack distribution tends to be unsaturated under freezing and thawing environment, and the re-hydration reaction is hindered. The pore structure near the crack varies under different environments.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Xin Xiao, Jingwei Li, Qingke Meng, Xiangshan Hou, Yanhui Liu, Xujiang Wang, Wenlong Wang, Shengtao Lu, Yuzhong Li, Yanpeng Mao, Tong Li
Summary: Preparing gypsum-based self-leveling mortar (GSLM) using beta-hemihydrate gypsum and solid wastes-derived sulfoaluminate cement (WSAC) can improve the mechanical performance of the mortar, but phosphorus impurities can weaken the hydration speed and degree.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Sihang Bao, Junzhen Di, Yanrong Dong, Ziqing Gao, Qing Gu, Yuanfang Zhao, Hongyu Zhai
Summary: Tailings dam break and leakage accidents pose a threat to the safety of people in mining areas and cause severe environmental pollution. This study focuses on solidifying tailing sand using microbial induced calcite precipitation (MICP) to improve strength and fix heavy metals. The curing time of MICP bio-cemented tailings is found to significantly impact the strength of tailings, while its effect on heavy metal fixation is minimal. The optimized MICP curing time is 10 days, resulting in improved strength and cementation of tailings particles.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Ferhat Benmahiddine, Fares Bennai, Achraf Charaka, Ameur El Amine Hamami, Abdelkader Tahakourt, Rafik Belarbi
Summary: This paper studied the effects of hysteresis on the hygrothermal behavior at the building scale. Through laboratory validation and numerical simulations, it was found that hysteresis has a significant impact on the relative humidity and total heat fluxes in buildings, while it does not have a noticeable effect on temperature variations.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
You Gao, Wei He, Xiayang Zhang, De'an Sun, Pei Li
Summary: This study determined the boundary line between the swelling and compression deformation zone in lateritic clay through wetting tests, and proposed a simple bimodal SWRC model. It also found that the existing strength model underestimated the tested values in the medium to high suction range, therefore a segmented strength equation was introduced for enhanced predictions of the strength properties of lateritic clay.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Prabhath Ranjan Kumar Soda, Asheer Mogal, Kalyan Chakravarthy, Nikhil Thota, Nimish Bandaru, Sanjay Kumar Shukla, K. M. Mini
Summary: This study investigates the use of encapsulated bacteria to improve the self-healing ability of concrete. Through various tests, it is found that using 20% cement-coated alginate beads (CCAB) and 5% nanosilica (NS) can achieve optimal strength and healing. This research is significant for enhancing the durability of concrete.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Shizhe Wang, Haiping Wu, Wen Yang, Wei Wang, Zhibo Zhu, Kun Nie, Luoxin Wang, Hua Wang, Jing Wu
Summary: In this study, photothermal-heat storage concrete (PHSC) was developed with excellent photothermal conversion performance and heat storage capacity. By absorbing and storing solar energy during the day and releasing it at night, PHSC can effectively reduce energy consumption in buildings.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Robin Deb, Jialuo He, Geetika Mishra, Yaghoob (Amir) Farnam
Summary: Incorporation techniques of phase change materials in cementitious composites have a significant influence on thermal properties. This study investigated the thermal behavior of low-temperature PCM when subjected to varying temperature change rates and pore confinement inside the porous network of lightweight aggregates. The results showed that ramp rates affect the nucleation and crystallization growth process during the phase transition, and the pore structure of the aggregates affects the supercooling phenomenon and confinement pressure of the PCM.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Eduardo Ferreira, Payam Sotoudeh, Dagmar Svecova
Summary: This study investigates the fatigue behavior of concrete under different stress reversal conditions. The results indicate that stress reversal generally causes more severe damage and reduces the cycles to failure compared to tensile fatigue. Additionally, adding some level of compression contributes to the energy required for failure under stress reversal fatigue. Specimens with higher concentration of fractured aggregates achieve longer fatigue lives.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Mag Raj Gehlot, Sandeep Shrivastava
Summary: This study evaluates the compatibility relationship between plaster bonds and the substrate under an accelerated aging environment, and finds that incorporating an appropriate amount of granite cutting waste can improve the strength parameters and adhesion of the cement mortar.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Min Zhang, Qirui Luo, Mingke Deng, Shixing Zhao
Summary: This study investigated the bond behavior between carbon FRCM composites with added short fibers and concrete substrates. The effects of different factors were considered and 36 specimens were tested and discussed. The experimental results were analyzed in terms of failure mode, load-slip curve, and characteristic parameters, and the contribution of weft yarns was taken into account in the developed bondslip model.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Dengkai Liu, Hongniao Chen, Ray Kai Leung Su
Summary: The susceptibility of building stones to fire and high temperature was investigated in this study by examining their physical and mechanical properties. The results show that both compressive and tensile properties of stones are affected by temperature changes. The tensile strength is particularly sensitive to temperature changes, requiring special attention to the components subjected to tensile stress in stone buildings. Principal component analysis was used to predict the mechanical properties of stones, providing a new method for calculating the residual mechanical properties after high temperature or fire.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Joso Maria Raposo, Eduardo Cavaco, Luis Costa Neves, Eduardo Julio
Summary: This paper investigates the correlation between the friction coefficient and the surface roughness of concrete-to-concrete interfaces. Experimental tests were performed on specimens with different surface treatments, and the surface roughness parameters were analyzed and correlated with the shear strength and friction coefficient. The results showed that certain roughness parameters had a strong positive correlation with the friction coefficient, while others had little or no correlation. A novel combined roughness parameter with optimized correlation was proposed.
CONSTRUCTION AND BUILDING MATERIALS
(2024)
Article
Construction & Building Technology
Chiara Riccardi, Massimo Losa
Summary: The interest in using bio materials in asphalt pavements is growing due to economic reasons and environmental benefits. This study aimed to review the use of bio extenders as additives in binders, with a focus on replacements greater than 20% of fossil binder. The properties of bio-extended binders were found to vary substantially depending on the biomass source and production process.
CONSTRUCTION AND BUILDING MATERIALS
(2024)