田 倩,王育江,张守治,姚 婷,徐 文,刘加平
基于温度场和膨胀历程双重调控的侧墙结构防裂技术
田 倩,王育江,张守治,姚 婷,徐 文,刘加平
摘 要:地下室侧墙混凝土裂缝是建筑结构工程裂缝控制的关键和难点。本文基于工程实体结构的调研与监测数据,分析了地下室侧墙结构开裂机制。采用新型的水泥水化放热速率调控化学外加剂,一方面降低水泥水化加速期的放热速率,为结构散热赢得时间,削弱温峰;另一方面与膨胀剂复合时,延缓结构升温速度有助于调控膨胀剂的膨胀历程,建立更加有效的膨胀预压应力,提高膨胀剂的补偿收缩能力。通过结构温度场和膨胀历程双重调控技术,有效解决了地下室工程侧墙混凝土开裂问题。
Abstract: Sidewall cracking of underground structure is the most difficult and key point for the cracking inhibiting of building structures. In this paper, the cracking mechanism of such kind of structure is analyzed based on the investigation and site-monitoring data from real engineering projects. A new type of chemical admixture is developed to adjust the hydration heating rate of cement. The proposed admixture could, on one side, reduce the hydration heating rate of cement during the accelerating stage, provide more time for the radiating of structure and thus lower the temperature peak effectively; on the other side, when composed with expansive agent, the delayed heating rate of the concrete structure could adjust the expansion history of expanding agent and build more effective expansion pre-stress and thus enhance the shrinkage-compensating effect to a large extent. The application of this dual-regulation technology of temperature field and expansion history effectively resolve the practical side-wall cracking problems for real underground engineering projects.
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