受控渗透性模板对混凝土结构耐久性影响的对比试验

泵送混凝土中含有大量游离水,若这些游离水不在混凝土硬化前排出,就会给混凝土结构留下永久的隐患。渗透性模板既能排水,又能保水,使表层混凝土的水胶比降低,提高强度,同时改善混凝土脱模前的养护条件,使混凝土表层具有较高的抗裂性,因此,也可作为防止或控制混凝土表层早期开裂的一项有效措施。试验还表明,国产与进口渗透性模板布的性能差距不大,性价比相当,均可明显提高混凝土构件表层的抗氯离子扩散性能。

Comparative Experiments for Effects of Controlled Permeability Formwork on Durability of Concrete Structure

Pumped concrete contains a substantial amount of free water.Should the free water not discharged before the concrete hardens,there would be potential problems left with the concrete structure.Capable of both discharging and preserving water,the permeability formwork reduces the water-binder ratio of the surface layer of concrete and enhances its strength.It also improves the curing condition of the concrete before demoulding,giving the surface layer of concrete high crack resistance.Therefore,the use of the permeability formwork is an effective way of preventing or controlling the process of early stage crack of the concrete surface.Additionally,tests have shown that the domestic and the imported permeability formworks have similar quality and performance price ratio.They are both able to limit the spread of chloride ions in the concrete surface.