表面保温材料对施工期大体积混凝土温度的调控作用

The Role of Surface Insulation Materials in Regulating the Temperature of Mass Concrete During Construction

大体积混凝土作为重要的结构材料,具有水化程度高、温度扩散面积大等特点。然而,大体积混凝土有时不可避免需要在寒冷条件下施工,在常规的材料组成设计下形成的混凝土易出现温度裂缝,进而影响其后期力学性能。因此,以某地下空间工程项目为背景,深入研究了大体积混凝土温度调控方法;结合工程中混凝土的施工条件和环境,研究了表面保温材料对大体积混凝土各关键点位温度的调控效果。研究结果表明,低温下浇筑的大体积混凝土,其内部温度受外部环境影响较小,但表层温度对环境温度变化敏感性高,易发生温度骤降现象。XPS保温材料能够通过保温作用降低各点位的温度下降速率,使混凝土内部的温度梯度分布更加均匀;此外,利用内部的热量传递作用,可以调节表层温度的时程分布,减小因昼夜温差变化导致的温度骤降,还可以进一步降低混凝土形成微观缺陷的可能,保证混凝土在低温条件下的养生环境满足强度形成需求。因此XPS保温材料可用于大体积混凝土。

As an important structural material,the mass concrete has characteristic of high degree hydration and large temperature diffusion area.However,it is sometimes constructed under cold conditions and the concrete formed under conventional material composition design is prone to temperature cracks,which affect its later mechanical properties.Therefore,taking an underground space project as an example,the temperature control method of mass concrete was studied intensively;The effect of surface insulation materials on the temperature control of mass concrete at each key point was studied in conjunction with the construction conditions and environment of concrete in the project.The research results show that the internal temperature of the mass concrete poured at low temperature is less affected by the external environment,but the temperature of the surface layer is highly sensitive to environmental temperature changing and prone tosuddenly lower temperature.The extruded polystyrene board(XPS)insulation materials can reduce the temperature drop rate at each point by the insulation effect so that the temperature gradient inside the concrete is more uniformly distributed;In addition,the internal heat transfer effect can not only regulate the time distribution of the surface temperature,reduce the temperature drop caused by the temperature difference between day and night,but also further reduce the possibility of the formation of microscopic defects in concrete to ensure that the concrete in low-temperature conditions to meet the needs of strength formation of the permaculture environment.Therefore,XPS insulation materials can be applied in mass concrete.