Low carbon ultra-high performance engineered geopolymer composite and its preparation method and application

A preparation method for an ultra-high performance engineered geopolymer composite, wherein the composite comprises:

• cementitious material powder 1163 parts, fine aggregate 407.1 parts, admixture 18.6 parts, nano calcium carbonate 23.3 parts, reinforcing fiber 19.4 parts, activator 475.9-932.2 parts, and water 49.7-81.6 parts;
• the cementitious material powder comprises the following parts by weight of raw materials:
• slag 821.1 parts, fly ash 248.9 parts, and silica fume 93.0 parts;
• the admixture comprises the following parts by weight of raw materials:
• barium chloride 11.6 parts, defoaming agent 1.2 parts, and water reducer 5.8 parts;
• the fine aggregate is quartz sand;
• the activator used is a NaOH Na2SiO3 activator as a basic activator, and Na2CO3 is used as a supplementary activator to form a composite activator, wherein, a mass ratio of NaOH solution, Na2SiO3 solution, and Na2CO3 solution is (74.6-111.5):(0-119.1):(278.7-433.5);
• the reinforcing fiber is an ultra-high molecular weight polyethylene fiber;
• and the method comprises the following steps:
• (1) after mixing uniformly the cementitious material powder, barium chloride, and defoaming agent, adding successively quartz sand, activator, water reducer, nano calcium carbonate and PE fiber and stirring uniformly to obtain a slurry;
• (2) pouring and forming the obtained slurry and maintaining, then obtaining the ultra-high performance engineered geopolymer composite;
• step (1) comprises the following steps:
• adding the cementitious material powder, barium chloride, and defoaming agent to a stirrer, and dry mixing at a stirring rate of 75 r/min for 3 min, then adding the quartz sand to the stirrer and dry mixing at a low speed of 75 r/min for 3 min, then mixing the activator with water and adding to the stirrer to stir at a low speed of 75 r/min for 1 min, then stopping the stirrer and adding the water reducer and nano calcium carbonate to continue to stir at a stirring rate of 165 r/min for 2 min, then replacing with a low speed of 75 r/min and adding all PE fibers within 3 min, finally, dispersing uniformly the fibers under stirring at a low speed of 75 r/min for 2 min.