A scientometric review of geopolymer concrete

Research has shown that alkali-activated concrete (AAC) is comparable to ordinary Portland cement concrete (OPCC) in terms of mechanical properties and may offer ecological benefits compared to OPCC. This study evaluates the energy and emission of AAC and OPCC across different classifications of concrete compressive strength (40, 60, and 100 ​MPa). Analysis indicates that the selection of constituent materials can substantially affect the energy and emission of AAC and OPCC. Ordinary Portland cement (OPC) is the principal contributor to the energy and emission of OPCC, accounting for 80% of energy and 91% of emissions of OPCC. The activating solution, meanwhile, is the main contributor to the energy and CO2 emission of AAC. Normal strength AAC (40 ​MPa) shows 46% less energy and 73% less CO2 emission than OPCC. However, high-strength AAC (60 ​MPa), using metakaolin as a base material, experiences higher energy (8%) than OPCC yet the emission is 40% less than OPCC. A substitution of fly ash for metakaolin results in superior efficiency of AAC compared to OPCC. Two mixtures of ultra-high-strength AAC (100 ​MPa) result in contradictory findings. One mixture with a sodium hydroxide and silica fume activating solution shows 5% and 30% less energy and CO2 emission, while the other mixture with a sodium hydroxide and sodium silicate activating mixture is less efficient than OPCC.

Energy and CO2 emission assessments of alkali-activated concrete and Ordinary Portland Cement concrete: A comparative analysis of different grades of concrete

Geopolymer is emerging as a potential alternative material to the ordinary Portland cement (OPC) owing to its energy efficiency and environmental protection. However, the effect of the mix design parameters on the behavior of geopolymer concrete (GPC) produced using local metakaolin (MK) is not well established. This paper presents findings from a comprehensive experimental program to study the effect of various mix design parameters on the properties of fresh and hardened MK-based GPC. Seventeen mixes were cast in four groups to investigate the effect of four parameters, including sodium silicate to sodium hydroxide ratio, alkaline solids to MK ratio, aggregate content, and water to solids ratio on the properties of GPC. The investigated properties included workability, density (wet and dry), development of compressive strength with age, splitting tensile strength, ultrasonic pulse velocity, water absorption, and horizontal abrasion resistance. Besides, two reference OPC concrete mixes, equivalent to two MK-based geopolymer mixes, were tested for the sake of comparison. The test results were helpful in developing a better understanding of the behavior of MK-based GPC. Some useful models are proposed for predicting workability, splitting tensile strength, water absorption, and weight loss in abrasion for MK-based GPC. The test results were supplemented and confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis performed on some selected GPC mixes.

Divyank Manish

Papers

Study of mechanical and microstructural properties of geopolymer concrete with GGBS and Metakaolin