新型胶凝材料体系的抗裂性能

Anti-cracking Performance of New Cementitious Material System

结构开裂问题一直困扰着现代混凝土工程,引起混凝土结构开裂的因素有很多,其中水泥的“三高”问题,即高硅酸三钙、高铝酸三钙、高细度是引起开裂的主要原因。本通过降低胶凝材料中水泥熟料的比例、采用粗磨而成的水泥熟料以及提高胶凝材料中矿物掺和料比例的方法配制出低碳胶凝材料这种新型胶凝材料体系,并将其与现行搅拌站常用胶凝材料体系进行抗裂性能的对比,应用自主研发设计的“方圆抗裂模具”研究两种胶凝材料体系的抗裂性能,同时结合水化热做进一步的分析。研究表明:低碳胶凝材料这种新型胶凝材料体系所体现的抗裂性能和当前搅拌站所采用的胶凝材料体系进行比较具有非常大的优势;此外对于低碳胶凝材料而言,它的水化放热量和水化放热速率低于现行搅拌站常用胶凝材料体系;掺加一定量的钢渣、膨胀剂能够显著提高低碳胶凝材料的抗裂性;SO_(3)含量低会增加低碳胶凝材料的开裂敏感性。

Structural cracking is a common problem that has always plagued modern concrete engineering.There are many factors affecting concrete cracking and the“three highs”of cement,namely high C 3S content,high C 3A content and high fineness is the main reason.In this paper,a new type of low-carbon cementitious material system was formulated by reducing the proportion of cement clinker in cementitious materials,using coarsely ground cement clinker and increasing the proportion of mineral admixtures in cementitious materials.Compared with the cementitious material system commonly used in the current mixing plant,apply the self-developed“square and round anti-crack mold”to study the crack resistance of the two cementitious material systems,and combine the heat of hydration for further analysis.The research shows that the crack resistance of the new type of low-carbon cementitious material system is significantly better than that of the current cementitious material system commonly used in the mixing plant.The heat of hydration heat is lower than that of the commonly used cementing material system in the mixing plant.Adding a certain amount of steel slag and expansion agent can significantly improve the crack resistance of low carbon cementitious mate-rials,and low SO_(3) content will increase the cracking sensitivity of low carbon cementitious materials.