防射线大体积混凝土施工的防裂措施

国内大型医院的放射操作室常设计为大体积混凝土，利用混凝土本身的厚度、密实度及质量来防放射线的穿透。但大体积混凝土施工中常会产生施工裂缝，以致降低了它防放射作用的效果。为了防止大体积混凝土施工出现裂缝，除了采取调整混凝土配合比设计、施工模板结构设计、支撑体系设计等技术措施外，还需要对大体积混凝土底板、墙体和顶板处采用技术保温措施。现结合某工程施工实例，将混凝土内外温差控制在25℃以内能有效防止裂缝出现，从而确保了混凝土的施工质量，达到了大体积混凝土防射线的效果。

Crack Control in Construction of Radiation-Shielding Massive Concrete

Radiation operating-rooms in domestic big hospitals are usually designed as massive concrete structure, which has enough depth, density and quality itself and can prevent ray penetration. But construction cracks in massive concrete frequently occur, which leads to lower ray-shielding efficiency. To prevent massive concrete from cracking, not only should the concrete mixture, formwork design and bracing system design be adjusted, but also some effective thermal-insulating techniques on concrete slabs and walls are applied in construction. Certain engineering construction case showed that it is efficient for avoiding cracks to control temperature difference between internal and external concrete within 25 ℃, which ensuring the high construction quality and ray-shielding function of massive concrete.