硅钙渣混凝土温升调控机理研究

The hydration heat of cement can increase sharply the temperature of concrete. Because of its poor thermal conductivity and heat emission capacity, an obvious temperature difference is formed between the inside and outside of the concrete, and the thermal stress appears in the concrete. This will result the temperature cracks in the concrete, and the durability of concrete construction will be reduced. Calcium silicate slag is the residue generated from the comprehensive utilization of fly ash, and its main component is dicalcium silicate (beta -C2S). Slow hydration heat and less hydration heat are its features. So the calcium silicate slag can be used to control the hydration heat of cement, reduce the temperature increase of concrete, and reduce the temperature stress of concrete. Besides, the emissions of calcium silicate slag can be reduced, the occupied area of land can be reduced, and the natural environment can be protected. In this program, research objects include the calcium silicate slag, calcium silicate slag-cement mixed cementitious materials and the concrete with calcium silicate slag. The research methods include experimental study, microscopic scanning and theoretical analysis. Four research contents include hydration characteristics, hydration heat, adiabatic temperature rise and control design. The research results are expected to be used in the large volume concrete engineering, such as piers, dams, foundations, shafts, and so on. Research background and theoretical basis will be provided for treatment of the calcium silicate slag, protection of the natural environment and solving the technical difficulty in the hydration heat control.

水泥水化热可引起混凝土内部温度急剧升高，由于混凝土导热性能差，内部热量散发慢，在内、外之间形成了明显的温度差，出现温度应力，致使混凝土产生温度裂缝，影响混凝土建（构）筑物的耐久性。硅钙渣是粉煤灰综合利用过程中产生的残渣，主要成分是硅酸二钙（β-C2S），具有水化放热速度慢、放热量少的特性。因此，可利用硅钙渣调控水泥水化热，降低混凝土温升。同时，还能缩减硅钙渣排放量，减少土地占用面积，保护自然环境。本项目拟以硅钙渣、硅钙渣-水泥混合胶凝材料、硅钙渣混凝土为研究对象，采用试验研究、微观扫描、理论分析相结合的研究方法，从水化反应特征、水化放热试验研究、温升调控试验研究、温升计算与调控设计4个方面，开展硅钙渣混凝土温升调控机理的研究工作。研究成果有望应用于桥墩、大坝、基础、井筒等大体积混凝土工程中，以期为处理硅钙渣废弃物，保护自然环境，解决温升调控技术难题，提供试验依据和理论基础。

水泥水化热可引起混凝土内部温度急剧升高，由于混凝土导热性能差，内部热量散发慢， 在内、外之间形成了明显的温度差，出现温度应力，致使混凝土产生温度裂缝，影响混凝土建 （构）筑物的耐久性。基于这一工程背景，本项目利用硅钙渣主要成分硅酸二钙具有水化放热速度慢、放热量少的特性, 调控水泥水化热，降低混凝土温升。以硅钙渣、硅钙渣-水泥混合胶凝材料、硅钙渣混凝土为研究对象，采用试验研究、微观扫描、理论分析相结合的研究方法，从水化反应特征、水化放热试验研究、温升调控试验研究、温升 计算与调控设计4个方面，开展硅钙渣混凝土温升调控机理的研究工作。研究结果表明，用硅钙渣替代混凝土中水泥，可减少30%的水化放热量，显著降低混凝土温升。研究成果可应用于桥墩、大坝、基础、井筒等大体积混凝土工程中，解决温升调控技术难题，并处理硅钙渣废弃物，保护自然环境。