Abstract
The use of tailings, waste rock, fly ash, and slag to prepare geopolymer concrete can effectively solve the problems of land resources occupied by tailings and waste rock, low utilization rate, and environmental pollution. Using a dry-wet circulation method, fly ash for a different corrosion solution to geopolymer concrete (referred to as TWGPC) was analyzed. Through an appearance change, the corrosion resistance coefficient of the compressive strength, relative dynamic elastic modulus, tensile splitting strength, relative mass, and durability were investigated, using scanning electron microscopy (SEM) analysis of the microstructure, The life of TWGPC was predicted based on the GM(1,1) prediction model of grey system theory. The test results show that with an increase in the number of dry-wet cycles, the surface of the specimen crystallizes, cracks, spalls, and exhibits other phenomena. The compressive strength corrosion coefficient, relative dynamic elastic modulus, crack tensile strength, and relative mass show a trend of increasing first and then decreasing, finally reaching the peak value after 40 cycles. The erosion products generated by the early reaction fill the slurry aggregate pores and improve the strength of TWGPC. In a later stage, a large number of erosion products absorb water and expand; the internal pores of TWGPC are connected, leading to a decrease in strength. Cl- inhibits the corrosion of SO42- in concrete and improves the durability of concrete.
Highlights
The world produces nearly 14 billion tonnes of solid waste such as tailings and waste rock every year (Khaldoun et al 2016)
The use of tailings, waste rock, fly ash and slag to prepare geopolymer concrete can effectively solve the problems of land resources occupied by tailings and waste rock, low utilization rate and environmental pollution
Many scholars have carried out considerable research on the performance of geopolymer concrete composed of waste rock and tailings instead of aggregates and slag and fly ash (FA) instead of cementitious materials (Parathi et al 2021)
Summary
The world produces nearly 14 billion tonnes of solid waste such as tailings and waste rock every year (Khaldoun et al 2016). Chen et al (2016) studied the erosive effects of chloride salt and sulfate composite solutions on oridinary Portland cement (OPC) samples of FA slag under the action of a dry-wet cycle and found that a high-concentration composite solution could reduce OPC damage caused by this process. Previous studies have mainly analysed geopolymer concrete composed of tailings, waste rock, FA and slag in terms of the mixing amount, ratio and substitution rate as well as analysed concrete durability under dry-wet cycles and salt solutions. These studies have provided a theoretical basis for the use of solid waste and have promoted the development of geopolymer concrete and concrete durability in corrosive environments. The predicted results were compared with the appearance changes, macroscopic mechanical tests and microstructure analysis results, and the feasibility of the model was verified
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