热养护对矿物掺合料混凝土抗氯离子渗透性能及孔结构的影响研究

Research on Chloride Ion Penetration Resistance and Pore Structure of Mineral Admixtures under Thermal Curing

为研究热养护对矿物掺合料混凝土强度、耐久性的影响,文中通过对热养护下矿物掺合料高性能混凝土进行氯离子渗透试验和微观试验,研究热养护对矿物掺合料高性能混凝土抗氯离子渗透性能及孔结构的影响。结果表明,相较于标准养护,热养护在一定条件下能快速激发矿物掺合料活性,提升矿物掺合料高性能混凝土抗氯离子渗透性能,但过高的热养温度和过长的热养时间会使混凝土热损伤增大,增加孔隙率,导致抗氯离子渗透性能变差。80℃热养9 h后转标养28 d的混凝土电通量值为50℃的62%,72 h后为50℃的2.05倍。补充养护采用Ca(OH)_(2)饱和水溶液养护方式,对热养混凝土的抗氯离子渗透性能和孔径分布有一定的改善,但当热养温度过高时,补充养护的改善作用不明显。

In order to study the influence of thermal curing on the strength and durability of mineral admixture concrete,through the chloride ion penetration test and microscopic test of the mineral admixture high performance concrete under thermal curing,the influence of thermal curing on the chloride ion penetration resistance and pore structure of the mineral admixture high performance concrete is studied.The results show that compared with standard curing,thermal curing can quickly activate the activity of mineral admixtures under certain conditions and improve the resistance to chloride ion penetration of mineral admixture high-performance concrete.However,excessive heat curing temperature and excessive heat curing time will increase the thermal damage of the concrete,increase the porosity,resulting in the deterioration of the resistance to chloride ion penetration.The electric flux value under the curing conditions of heating curing at 80℃for 9 hours and then converting to standard feeding for 28 days was 0.62 times as much as that at 50℃,and after 72 hours it was 2.05 times as much as that at 50℃.In addition,the supplementary curing method adopts Ca(OH)_(2) saturated aqueous solution curing,which can improve the anti-chloride ion permeability and pore size distribution of the thermo-cured concrete.But when the thermo-curing temperature is too high,the improvement effect of the supplementary curing is not obvious.