铝酸钙水泥水化产物对铝酸钙水泥水化的影响

Influence of calcium aluminate cement hydration products on hydration of calcium aluminate cement

在铝酸钙水泥的生产、运输、储存过程中,会有部分水泥吸水而发生水化。为了研究这部分水化产物是否会对水泥的水化速度和水化产物产生影响,将Secar 71水泥经制浆、30℃养护、冷冻干燥、粉磨制成水化产物粉,再与Secar 71水泥配制成水化产物粉含量(w)分别为3%和30%的混合粉,然后以纯Secar 71水泥和纯水化产物作为参比,在30℃环境温度下测试它们的水溶解特性(以水灰质量比5 1的稀浆体的电导率-时间曲线表征)和水化特性(以水灰质量比2 5的浆体的温度-时间曲线表征);并经制浆(水灰质量比为2 5)、养护(30℃、100%相对湿度)、冷冻干燥后,分析试样的物相组成和显微结构。结果表明:在30℃环境温度下,引入铝酸钙水泥水化产物能够促进铝酸钙水泥的溶解和水化;含水化产物的混合粉水化后试样中有AH3存在,而纯Secar 71水泥水化后试样中几乎没有AH_3;含水化产物的混合粉水化后试样中C_2AH_8板片状结晶比纯Secar 71水泥试样的更加粗大。

A part of calcium aluminate cement （CAC） hydrates during the production, transportation and storage. The influence of these hydration products on the hydration speed and hydration products of CAC was researched. CAC hydration product powders were obtained by preparing Secar 71 slurry, curing at 30 ℃,freeze vacuum drying and milling. The hydration product powders were mixed with Secar 71 to pre- pare the mixture powders with 3% or 30% of hydration product powders. Then using pure Secar 71 cement and pure hydration products as the references,the dissolution characteristics （conductivity-time curve of dilute slurry with 5：1 of water to cement mass ratio） and hydration characteristics （temperature-time curve of slurry with 2：5 of water to cement mass ratio） of the mixture powders were tested at 30 ℃;and the phase composition and microstructure were analyzed after the slurry preparation （2：5 of water to cement mass ratio） ,curing at 30 ℃ with 100% relative humidity,and freeze drying. The results reveal that the intro- duction of calcium aluminate cement hydration products can promote the dissolution and hydration at 30 ℃;after hydration,AH3 exists in the mixture powders of Secar 71 cement and hydration products, but AH3 is not observed in the pure Secar 71 cement; after hydration, plate-like C2AH8 crystals in the mixture powders are bigger than those in pure Secar 71.