大体积混凝土配合比设计及裂缝防控技术研究

Research on mix proportion design and crack prevention and control technology of mass concrete

调整大体积混凝土配比可控制构件内部温度分布的梯度,实现裂缝防控。以粉煤灰和矿渣复掺比例为主要参数,对混凝土坍落度、抗压强度和水化热等进行了试验研究。结果表明,为矿物掺和量50%、粉煤灰和矿渣以7∶3的比例复掺、水胶比为0.45时,混凝土28 d抗压强度可达51.2 MPa,7 d水化热约为130 kJ/kg,符合低水化热、高体积稳定性、C35等级要求。经足尺模型试验及实际应用,最优配比下制备出的大体积构件,内部温度梯度分布合理,整体构件处于压应变状态,抗裂效果较好。

The temperature gradient distribution inside the component can be controlled by adjusting the mix proportion of the mass concrete to achieve crack prevention Varying the proportion of fly ash and slag,the concrete was tested to investigate the slump,compressive strength and hydration heat.The results show that when the mixing ratio is 50%of mineral admixture,the ratio of fly ash and slag is 7∶3,and the water-binder ratio is 0.45,the 28-day compressive strength of the concrete can reach 51.2 MPa,and the 7-day hydration heat is about 130 kJ/kg.It meets the requirements of low hydration heat,high volume stability and C35 grade.After full-scale model experiment and practical application,the mass components prepared under this optimal mix proportion have reasonable internal temperature gradient distribution,and the overall component is in a compressive strain state.The crack resistance effect is better.