氯盐侵蚀后不同掺合料混凝土力学性能

Mechanical Properties of Concrete Mixed with Mineral Admixture after Chloride Corrosion

目的为得到氯盐侵蚀混凝土基本力学性能随掺合料的变化规律,对不同掺合料混凝土在氯盐腐蚀后进行试验研究.方法将脱模后的100 mm×100 mm×100 mm立方体试块进行标准养护28 d,然后放入人工海洋环境模拟室进行氯盐侵蚀试验,盐雾质量浓度为5%NaCl溶液.当氯盐侵蚀110 d后,对试块进行单轴压缩试验,测定其基本力学性能.结果单掺粉煤灰时,粉煤灰掺合比为20%和35%时,混凝土的脆性较未掺加矿物掺合料混凝土增强,掺合比为50%时,混凝土的塑性较未掺加矿物掺合料混凝土增强;相同掺合比下(50%),单掺矿粉、单掺粉煤灰和复掺混凝土均出现明显的压实阶段,且掺有50%矿粉的混凝土压实阶段明显长于单掺粉煤灰和复掺混凝土.结论试验中大多掺合料都降低了混凝土的变形模量;单掺粉煤灰(20%和35%)以及复掺均能提高混凝土强度,且复掺效果最好.

In order to get variation laws for mechanical properties of the concrete mixed with dif- ferent mineral admixture after chloride corrosion, some tests of this concrete were carried out in this paper. Test cubic blocks with dimension 100 mm3 were conserved for 28 days and then placed in a artificial marine environment simulation room for chloride corrosion experiment, and the salt spray was generated by the NaC1 solution with 5 % concentration. When the concrete was eroded by chloride salt for 110days, uniaxial compression experiments were carded out to obtain basic mechanical properties of the concrete. Results show that the brittle of concrete mixed with 20% and 35% single fly ash is reinforced;but the plastic of concrete mixed with 50% fly ash can be en- hanced,compared with the concrete without mineral admixture. By the same mixed ratio（50% ）,the compaction stages of concrete mixed with single mineral powder, single fly ash, mineral pow- der and fly ash （ compound admixture） are all observed. The compaction stage of concrete mixed with 50% slag is the most obvious. It indicates that the deformation modulus of concrete can be decreased by mineral admixture. Single fly ash（ 20% and 35 % ）and compound admixture can both improve the strength of concrete, but the effect of compound admixture is the best.