摘要
通过对四种不同配合比的混凝土先后进行冻融循环试验(0、50、150次)和加速碳化试验(0、1、2周),研究冻融前后混凝土碳化性能变化情况。结果表明:冻融循环增大了混凝土孔隙率,加速了碳化进程,循环次数越多,加速作用越大;在冻融和高浓度CO2环境下,粉煤灰的掺入增加了混凝土碳化量,并造成较大强度损失,对混凝土结构不利;碳化使混凝土抗压强度略有提高,但不足以弥补冻融造成的强度损失,水灰比越大,强度损失越大。对混凝土结构进行耐久性设计和使用寿命预测时,必须考虑冻融、碳化及其它因素的复合作用。
Four different types of concrete had been studied aider exposure to 0,1,2 weeks carbonation after 0,50,150 freeze-thaw cycles to investigate into the effect of freeze-thaw action on carbonation of concrete.Results show that increased porosity, which is induced by freeze-thaw cycles,accelerated the carbonation process;and this accelerating effect becomes more evident with increasing number of freeze-thaw cycles.If exposed to freeze-thaw cycles in an atmosphere with high CO2 content carbonation of concrete prepared with fly ash is particularly accelerated;and its compressive strength is sharply decreased.The compressive strength of ordinary concrete increases slightly by carbonation but is reduced by the combined action of freeze-thaw cycles and carbonation;the strength loss becomes more evident as the water-cement ratio increases.Freeze-thaw action, carbonation and other deteriorated factors should be taken into account with respect to the durability design and service life prediction of concrete structures.
出处
《混凝土》
CAS
CSCD
北大核心
2007年第5期6-8,11,共4页
Concrete
基金
国家自然科学基金(50378045)
关键词
冻融循环
碳化
CACO3
含量
抗压强度
freeze-thaw cycles
carbonation
CaCO3 content
compressive strength
