碱激发-大矿物掺合料体系作为预制混凝土(PC)胶凝材料的环境效应研究

Environmental Impact of Alkali-activated Large Mineral Admixture System as a Substitute for Cementitious Material in Precast Concrete(PC)

研究一种碱激发-大矿物掺合料体系作为预制混凝土(PC)的胶凝材料的替代品,其可以大量地减少水泥用量,同时确保早期的出厂强度。结果表明,当Na_(2)SiO_(3)和NaOH组合激发剂的SiO_(2)/Na_(2)O=1.5,Na_(2)O含量为4%时,碱激发-大矿物掺合料胶凝体系的早期强度与蒸养水泥相近,其主要原因是碱激发-大矿物掺合料胶凝体系与蒸养水泥内部发生了相近程度的化学反应,微观结构具有一致的密度,两者的差别主要在于碱激发-大矿物掺合料净浆是N-A-S-H与C-A-S-H组合的复合型凝胶,而水泥净浆则以C-A-S-H为主。采用碱激发-大矿物掺合料胶凝体系作为PC的胶凝材料,可以降低30%以上的CO_(2)排放。

This study investigates an alkali-activated large mineral admixture system as a replacement for cementitious materials in precast concrete(PC).This system has the potential to significantly reduce the use of cement while ensuring early factory strength.The findings indicate that when the SiO_(2)/Na_(2)O ratio of Na_(2)SiO_(3) and NaOH is 1.5 and the Na2O content is 4%,the early strength of the alkali-activated large mineral admixture cementitious system is similar to that of steam-cured cement.The primary factor is that the alkali-activated large mineral admixture cementitious system exhibits a comparable level of chemical reaction to steam-cured cement,resulting in a consistent microstructure density.The alkali-activated large mineral admixture paste forms a composite gel of N-A-S-H and C-A-S-H,whereas the cement paste is primarily characterized by the dominance of C-A-S-H,which is the main difference between them.Using an alkali-activated large mineral admixture cementitious system as the cementitious material of PC can lead to a reduction in CO_(2) emissions by more than 30%.