胶砂比对低钙固碳胶凝材料砂浆碳化硬化性能的影响

Effect of cement-sand ratio on carbonation hardening properties of low calcium CO_(2) sequestration binder mortar

为了降低生产高性能预制建材制品过程中二氧化碳的排放,用工业原料石灰石和砂岩在1275℃煅烧制备了一种低钙固碳胶凝材料,研究了胶砂比(1∶0、1∶1、1∶2、1∶3)对低钙固碳胶凝材料碳化程度及砂浆早期碳化硬化性能的影响规律,并通过XRD、TG-DTA、FT-IR、SEM、纳米压痕、压汞仪等研究了碳化低钙固碳胶凝材料浆体与硅质河砂骨料的界面矿物组成、孔隙率及微观力学性能演变规律。结果表明,随着胶砂比的降低,固碳胶凝材料的碳化程度显著提高;而胶砂比为1∶1时砂浆的抗压强度最高,碳化养护24 h抗压强度达到46.9 MPa;继续降低胶砂比,砂浆的碳化硬化性能下降,可能与碳酸钙晶体在界面过渡区的富集有关。

To produce high-strength prefabricated building materials and reduce their CO_(2) emissions,a low calcium CO_(2) sequestration binder(LC-CSB)is prepared by calcining industrial raw materials limestone and sandstone at 1275℃.The influence of cement-sand ratio(1∶0,1∶1,1∶2,1∶3)on the carbonation degree and the early carbonation hardening performance of LC-CSB mortar is investigated,and the XRD,TG-DTA,FT-IR,SEM,nano-indentation and mercury intrusion porosimeter are used to study the evolution of mineral composition,porosity and micromechanical properties at the interfacial transition zone between carbonated LC-CSB paste and siliceous river sand aggregate.The results show that with the decrease of cement-sand ratio,the carbonation degree of LC-CSB increases significantly.While the compressive strength of the mortar is the highest at the cement-sand ratio of 1∶1,the compressive strength reaches 46.9 MPa after 24 h of carbonation curing.The carbonation-hardening properties of the mortar decrease with the continued decrease of the cement-sand ratio,which might be related to the enrichment of calcium carbonate crystals in the interfacial transition zone.