-3℃养护条件下矿物掺合料对混凝土强度和孔隙结构的影响研究

Effect of mineral admixtures on strength and pore structure of concrete at -3℃curing condition

为了研究不同养护条件下矿物掺合料对混凝土强度和孔隙结构的影响,进行-3℃和标准养护条件下,复掺粉煤灰、矿粉和硅灰对混凝土抗压强度、孔隙结构的试验。结果表明:与标准养护相比,在-3℃养护条件下,矿物掺合料的掺入对混凝土抗压强度有下降趋势,但对其孔径均有优化作用。基准组、复掺10%粉煤灰+10%矿粉+1%硅灰组、复掺10%粉煤灰+10%矿粉+3%硅灰组,28 d龄期标准养护下出现细小孔的频率是负温养护1.122~1.259倍,56 d龄期标准养护下出现细小孔的频率是负温养护1.108~1.180倍,矿物掺合料对混凝土硬化含气量和平均气泡间距均有改善作用,在标准养护条件下的优化作用明显优于负温养护条件。

In order to study the effect of mineral admixtures on the strength and pore structure of concrete under different curing conditions,the tests on the compressive strength and pore structure of concrete with fly ash,mineral powder and silica fume were carried out under the condition of-3℃and standard curing conditions.The results show that,compared with the standard curing,the compressive strength of concrete can be reduced by the addition of mineral admixture at-3℃,but the pore size is optimized.The base group,10%fly ash+10%mineral powder+1%silica fume group and 10%fly ash+10%mineral powder+3%silica fume group,the frequency of small hole in 28 d age standard curing is 1.122~1.259 times the negative temperature curing,the frequency of small hole in the standard curing of56 d age is 1.108~1.180 times the negative temperature curing,and the mineral admixture is hardening gas in the concrete.Both the volume and the average bubble spacing are all improved,and the optimization effect under standard curing condition is obviously better than that under negative temperature curing condition.