With regard to the shortcomings of low early activity of natural volcanic rock powder,we used different chemical reagents to carry out the single-doped optimization and orthogonal composite test scheme,combined with X-ray diffraction and scanning electron microscope analysis,to reveal the influ-ence law and promotion mechanism of chemical composite excitation on the activity of volcanic rock powder cementitious system.The results showed that a single and compound addition of chemical reagents could improve the activity of volcanic powder cementitious system,and the activity index of 7 d age was the best.The maximum activity index could be increased to 73%by single doping.The orthogonal test determined that the reagent compound of 6%CaO+2%CaCO3+2%CaSO4·2H2O could increase the activity index of 7 d age to 85%.Micro hydration product testing found that the conversion rate of the gelling system prompted by the discovery of the chemical compound excitation early Ca(OH)2 to 3CaO·Al2O3·3CaSO4·32H2O(AFt)was accelerated,while the stable structure internal alkaline environment was maintained,the gelling system internal C-S-H gel and AFt crystal generation increased,hydration re-action accelerated,and the hydration product filling effect became obvious,thereby improving the early strength of the specimen.
volcanic rockgel sand testchemical activationorthogonal test
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