低强度等级水工混凝土耐久性提高措施

由于水工混凝土自身胶凝物质含量少,强度等级较低,因此混凝土成型后表观质量普遍较差,成为影响其致密性和渗透性的关键因素。为了有效地提高混凝土的耐久性,根据南水北调东线睢宁二站泵站混凝土工程高质量成型需求,探讨了普通模板和透水模板浇筑养护条件下低强度等级水工混凝土成型性能差异。泵站底板混凝土现场工艺试验及相关耐久性试验结果显示,对于不同配比的混凝土试样,采用透水模板布后,成型致密光滑,表面无缺陷或孔洞气泡,密实度得到不同程度的改善,回弹强度显著增长,冻融、碳化及冲磨等耐久性指标也有所提高。

Measures of Improving Durability of Low-strength Hydraulic Concrete

Hydraulic concrete contains low cementitious materials and has low strength grade. The surface quality of hydraulic concrete after forming is a key factor that affects the density and low-permeability of hydraulic concrete, and it is also an important factor to improve the durability of hydraulic concrete. Based on the high quality requirements of hydraulic concrete in the Suining 2nd Pumping Station of the Eastern Route of the South-to-North Water Diversion Project, the different qualities of low-strength hydraulic concrete with the moulds pasted controlled permeability framework liner (CPFL) and common moulds were investigated. The results based on the in-situ engineering tests and durability tests of hydraulic concrete at the bottom plane of pumping station showed that the surface of concrete with different proportions using CPFL is dense and smooth without any defects such as holes and bubbles, and the compactness has been improved and rebound strength has been increased greatly. Moreover, the durability indexes such as freeze-thaw, carbonation, and abrasion have also been improved. Consequently, using CPFL is an effective measure to strengthen the durability of low-strength concrete.