内养护条件下矿物掺合料对蒸养水泥砂浆性能的影响规律

Effect of mineral admixture on performances of steam-cured cement mortar under internal curing condition

采用陶砂作为内养护材料,探究内养护条件下粉煤灰、矿粉和硅灰3种矿物掺合料对于蒸养水泥砂浆性能的影响。发现硅灰和矿粉在蒸养条件下能加快火山灰反应,在早龄期(1、3、7 d)与28 d龄期内均能提高水泥砂浆的抗压强度和耐久性,而内养护条件下这种增强作用更加明显;粉煤灰由于其早期水化活性低,使水泥砂浆结构劣化,但在内养护条件下该现象得到改善。上述结果主要是由于陶砂的加入提高了水泥砂浆的整体水化程度。此外,陶砂由于其多孔结构,虽然能密实界面过渡区,降低蒸养砂浆氯离子扩散系数,但也会提高水泥砂浆表层吸水率。

LWA was used as the internal curing material,exploring the effect of three mineral admixtures of fly ash,slag and silica fume on the performance of heat curing cement mortar under the conditions of internal curing.It was found that the silica fume and slag accelerate the pozzolanic reaction under the heat curing conditions,and improve the compressive strength and durability of the cement mortar in the early age(1,3,7 d)and 28 d ages,while this enhancement was even more pronounced under the internal curing conditions.Because of its early hydration activity was low,fly ash deteriorated the structure of cement mortar,but this phenomenon was ameliorated under internal curing conditions.All the results were mainly due to the addition of LWA to improve the overall hydration degree of cement mortar.In addition,because of its porous structure,the LWA compacted the interfacial transition zone and reduced the chloride ion diffusion coefficient of the heat curing mortar,but it increased the surface water absorption of the cement mortar as well.