复合胶凝材料井壁高强混凝土的性能与水化机理

Properties and hydration mechanism of composite binder used in high strength shaft concrete

对于冻结法施工的高强井壁大体积混凝土,内壁的中心温度可达80℃,而井筒外壁内侧的温度在10℃左右,这种温度的差异必然导致井壁混凝土开裂,导致耐久性下降。针对这些问题,研究了适于井壁高强混凝土用复合胶凝材料的水化特征及其对C70混凝土性能的影响。结果表明:复合胶凝材料的总水化热是井壁混凝土用常规胶凝材料水化热的一半;从28 d到180 d,复合胶凝材料配制的C70混凝土抗压强度持续增长14.8%,且孔隙率低,有害孔减少,混凝土具有很好的抗裂性;XRD和SEM试验表明,复合胶凝材料配制的C70混凝土水化180 d后无Ca(OH)2晶体存在,主要水化产物为致密的Ⅲ型C-S-H凝胶。

For high-strength large volume shaft concrete, its center temperature of inner shaft can be up to 80 , while the inside of outer shaft is around 10 . This will inevitably lead to concrete cracking and durability reduction. To solve these problems, the hydration characteristics of composite binder applied to high strength shaft concrete and its effect on the properties of C70 concrete are investigated. The results show that the total hydration heat of the composite binder is one half of the conventional cementitious material. The compressive strength of C70 concrete with composite binder continuously grow by 14.8% from 28 d to 180 d. Its porosity is low, and its harmful pore reduces. The concrete has good crack resistance. XRD and SEM tests show that C70 concrete with composite binder is without Ca(OH)2crystal after hydrating for 180 d, and the main hydration product is a dense type III C-S-H gel. © 2015, China Coal Society. All right reserved.