Study on the mechanical properties and influencing mechanism of alkali activated low-carbon concrete
In response to the problem of carbon emissions generated during the production and utilization of ce-ment,and the decrease in mechanical properties of concrete prepared by replacing cement with solid waste ma-terials under high dosage conditions,this article uses 4％Na2SiO3 to alkali excite glass powder(GP),and then replaces 50％of cement to prepare low-carbon concrete.The results indicate that the mechanical properties of low-carbon concrete are much lower than those of ordinary concrete.The addition of Na2SiO3 improves the me-chanical properties of low-carbon concrete to a certain extent,and increases the compressive strength by 22.6％,27.5％,19.8％,and 17.2％at each age,respectively.The splitting tensile strength increased by 21.3％,20.6％,18.2％,and 16.3％.Na2SiO3 causes the abundant SiO2 in the glass powder to appear obvious deconstruc-tion phenomenon under the action of OH-,which makes it combine with Ca,Na,K and other elements inside the low-carbon concrete to generate more C-S-H gel,C-A-S-H gel,N-A-S-H gel.At the same time,it also pro-duces potassium A zeolite crystals with higher strength that other groups do not have,while reducing the macropore content of low-carbon concrete and optimizing the pore structure.This in turn leads to a significant improvement in the mechanical properties of low-carbon concrete.This study provides new ideas and insights for reducing carbon emissions and the use of large amounts of solid waste in concrete.
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