Effect of Ultrafine Metakaolin on the Properties of Mortar and Concrete

Abstract

This study investigated the influence of ultrafine metakaolin replacing cement as a cementitious material on the properties of concrete and mortar. Two substitution levels of ultrafine metakaolin (9% and 15% by mass) were chosen. The reference samples were plain cement concrete sample and silica fume concrete sample with the same metakaolin substitution rates and superplasticizer contents. The results indicate that simultaneously adding ultrafine metakaolin and a certain amount of polycarboxylate superplasticizer can effectively ensure the workability of concrete. Additionally, the effect of adding ultrafine metakaolin on the workability is better than that of adding silica fume. Adding ultrafine metakaolin or silica fume can effectively increase the compressive strength, splitting tensile strength, resistance to chloride ion penetration and freeze–thaw properties of concrete due to improved pore structure. The sulphate attack resistance of mortar can be improved more obviously by simultaneously adding ultrafine metakaolin and prolonging the initial moisture curing time.

De-aluminated metakaolin-cement composite modified with commercial titania as a new green building material for gamma-ray shielding applications

“…Zhang S. et al, 2021 compared the mechanical properties of specimens containing 100 wt% cement, 15 wt% ultra-fine MK and 15 wt% SF instead of cement. It was concluded that there is not much difference in compressive strength between the specimens containing 15 wt% MK and 15 wt% SF [26]. Zidi Z., et al, 2021 assessed the effect of curing conditions on the compressive strength of MK-based geopolymer.…”

The Effect of Crushed Glass and Metakaolin Waste in the Properties of Modified Concrete

“…One of the most common environmental impact abatement techniques in concrete industry is the replacement of cement and natural aggregates with mineral materials reclaimed from industrial waste [4][5][6][7][8][9][10].…”

The Effect of a Pozzolanic by-Product Containing Glass Powder and Metakaolin on the Properties and Aar Resistance of Mortar Incorporatring Crushed Glass

“…Therefore, the concrete industry currently faces major challenges in finding cost-effective strategies in reducing the carbon dioxide emissions from manufacturing Portland cement [2]. Using mineral materials reclaimed from industrial waste to replace cement and natural aggregates is one of the most common environmental impact abatement techniques in the concrete industry [3][4][5][6][7][8]. Different alternatives, such as crushed glass, glass powder and metakaolin, are considered to be viable solutions for a greener and more sustainable civil construction industry as these secondary raw materials are readily available [9][10][11].…”

“…Metakaolin is obtained via an endothermic reaction of kaolin. The dehydroxylation of kaolin starts at 450 °C and continues at a temperature up to 900 °C; amorphous metakaolin Al 2 Si 2 O 7 is obtained at a temperature above 925 -950 °C; at 1050 °C metakaolin transforms into spinel Si 3 Al 4 O 12 and mullite [7]. In terms of reactivity, metakaolin is one of the most effective pozzolans with reactivity of 954 mg Ca(OH) 2 /g compared to 427 g reactivity of silica microspheres and 875 g of fly ash [17].…”