Influence of SiO2 /Na2O molar ratio on mechanical properties and durability of metakaolin-fly ash blend alkali-activated sustainable mortar incorporating manufactured sand

Zhang, Peng; Kang, Luoyi; Zheng, Ying‐Ying; Zhang, Tianhang; Zhang, Biao

doi:10.1016/j.jmrt.2022.04.041

Cited by 49 publications

(15 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The obtained results prove similar mechanisms of structure formation and geopolymerization in comparison with the previously studied metakaolin-fly ash blend alkali-activated sustainable mortar [ 41 ].…”

Section: Resultssupporting

confidence: 82%

Structural Formation of Alkali-Activated Materials Based on Thermally Treated Marl and Na2SiO3

et al. 2022

View full text Add to dashboard Cite

Modern materials science is aimed towards abandoning Portland cement in the production of building materials. The scientific novelty of this study lies in its being the first time a comprehensive study of the structure formation of alkali-activated materials (AAM) based on thermally treated marl and Na2SiO3 is carried out. The tasks for achieving this goal were to characterize the thermally treated marl as a new binder, and to comprehensively research the microstructure, fresh, physical, and mechanical properties of the AAM based on the binder. Received active particles of marl with a smaller size than Portland cement have a specific surface area of 580–590 m2/kg. The mineral composition of heat-treated marl is characterized by calcium silicates, which guarantee good binding properties. The results of X-ray diffraction analysis of the samples based on the clinker-free binder of alkaline activation using opoka-like marl confirmed the presence of calcite, quartz, and feldspar close to albite, micas, and zeolites. The obtained products of the chemical interaction of the components of the binder confirm the effectiveness of the newly developed AAM. As a result of comparing several binders, it was found that the binder “thermally treated marl—Na2SiO3” is the most effective, since for specimens based on it, a maximum compressive strength of 42.6 MPa, a flexural strength of 4.6 MPa, and minimum setting time were obtained (start 26 min, end 32 min) as well as a water absorption of 10.2 wt.%. The research results will be of interest to specialists in the construction industry, since the proposed recipes for clinker-free cements are an alternative to expensive and energy-intensive Portland cement and provide the creation of strong and durable concrete and reinforced concrete composites.

show abstract

Section: Resultssupporting

confidence: 82%

Structural Formation of Alkali-Activated Materials Based on Thermally Treated Marl and Na2SiO3

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Splitting tensile strength is an extremely important strength index for concrete as it determines the formation and development of cracks on the tensile side of flexural members [110]. The addition of RA negatively influences the splitting tensile strength of concrete, whereas the addition of slag has a positive influence.…”

Section: Splitting Tensile Strengthmentioning

confidence: 99%

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Zhang¹,

Wang²,

Zheng³

et al. 2023

Journal of Renewable Materials

View full text Add to dashboard Cite

Using recycled aggregate (RA) and slag instead of natural aggregate (NA) and cement can reduce greenhouse gas emissions (GHGE) and achieve effective waste recovery. In recent years, RA has been widely used to replace NA in concrete. Every year, several researchers conduct investigations on the mechanical performance and durability of recycled aggregate concrete (RAC). Due to the loose and porous material properties of RA, the mechanical properties and durability of RAC, such as strength, carbonation resistance, permeability resistance and chloride ion penetration resistance, are greatly reduced compared with natural aggregate concrete. In contrast, concrete containing slag instead of NA and cement generally improved the strength of concrete and reduced the internal porosity of materials. Herein, we discuss the effects of RA and slag on the workability, compressive strength, splitting tensile strength, ultrasonic pulse velocity (UPV) value, and elastic modulus of concrete. The relationships between the compressive strength and the splitting tensile strength, UPV value, and elastic modulus are discussed, and the optimal substitution method is proposed. In addition, various equations for calculating the compressive strength of concrete based on performance factors related to the compressive strength are summarized.

show abstract

“…As a major greenhouse gas, carbon dioxide is responsible for the severe phenomenon of global warming [ 11 ], while producing 1 ton of Portland cement will produce approximately 1 ton of carbon dioxide gas [ 12 ]. Geopolymer is a new cementitious material with high silicon and aluminum contents and a three-dimensional Si-O-Al polymeric network structure composed of tetrahedral units [ 13 , 14 ]. Various combinations of mixing and processing parameters are considered to have a critical impact on geopolymers [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Municipal Solid Waste Incineration Fly Ash on the Mechanical Properties and Microstructure of Geopolymer Concrete

Niu

Zhang

Guo

et al. 2022

Gels

Self Cite

View full text Add to dashboard Cite

Geopolymers are environmentally friendly materials made from industrial solid waste with high silicon and aluminum contents, and municipal solid waste incineration fly ash (MFA) contains active ingredients such as Si, Al and Ca. According to this fact, a green and low-carbon geopolymer concrete was prepared using MFA as a partial replacement for metakaolin in this study. The mechanical properties of the MFA geopolymer concrete (MFA-GPC) were investigated through a series of experiments, including a compressive strength test, splitting tensile strength test, elastic modulus test and three-point bending fracture test. The effect of the MFA replacement ratio on the microstructure of MFA-GPC was investigated by SEM test, XRD analysis and FTIR analysis. MFA replacement ratios incorporated in GPC were 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% by replacing metakaolin with equal quality in this study. In addition, toxic leaching tests of MFA and MFA-GPC were performed by ICP-AES to evaluate the safety of MFA-GPC. The results indicated that the mechanical properties of MFA-GPC decreased with the increase of the MFA replacement ratio. Compared with the reference group of GPC without MFA, the maximum reduction rates of the cubic compressive strength, splitting tensile strength, axial compressive strength, elastic modulus, initiation fracture toughness, unstable fracture toughness and fracture energy of MFA-GPC were 83%, 81%, 78%, 93%, 77%, 73% and 61%, respectively. The microstructure of MFA-GPC was porous and carbonized; however, the type of hydrated gel products was still a calcium silicoaluminate-based silicoaluminate gel. Moreover, the leaching content of heavy metals from MFA-GPC was lower than that of the standard limit. In general, the appropriate amount of MFA can be used to prepare GPC, and its mechanical properties can meet the engineering requirements, but the amount of MFA should not be too high.

show abstract

Influence of SiO2 /Na2O molar ratio on mechanical properties and durability of metakaolin-fly ash blend alkali-activated sustainable mortar incorporating manufactured sand

Cited by 49 publications

References 45 publications

Structural Formation of Alkali-Activated Materials Based on Thermally Treated Marl and Na2SiO3

Structural Formation of Alkali-Activated Materials Based on Thermally Treated Marl and Na2SiO3

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Effect of Municipal Solid Waste Incineration Fly Ash on the Mechanical Properties and Microstructure of Geopolymer Concrete

Contact Info

Product

Resources

About