装配式PC构件节能增效用早强水泥的制备与应用

Preparation and application of early strength cement for energy saving and efficiency enhancement of assembled PC components

为了让装配式PC构件在免蒸养的条件下在一定时间内达到脱模强度,本文以早强早凝硅酸盐熟料为基础,研究了混合材和甲酸钙掺量对水泥物理力学性能的影响,制备出早强水泥并成功应用于装配式PC构件的生产。此外,利用等温量热仪、X射线衍射(XRD)、同步热分析(TG-DTG)对早强水泥和市售P·O 42.5R水泥的早期水化热和水化产物进行了对比研究。结果表明:早强水泥的配比为:熟料80%,混合石膏5%,石灰石7.5%,高钛矿渣7.5%,外掺2‰甲酸钙。早强水泥早龄期水化速率快于P·O 42.5R水泥,水化产物多,导致水泥石的密实度高,水泥强度相应提高。在较低温度养护时,早强水泥可大幅度提高混凝土12 h强度;在养护温度为20~30℃时,早强水泥制备的混凝土养护12 h即可满足脱模要求,可实现装配式PC构件生产节能增效。

In order to achieve the required strength of the assembled PC component within a specific time frame without steam curing,this study investigates the impacts of mixture and calcium formate content on the physical and mechanical properties of cement based on early strength and early setting silicate clinker.Consequently,a kind of early strength cement is developed and successfully applied in the production of assembled PC components.The early hydration heat and hydration products of early strength cement and commercial P·O 42.5R cement are compared using isothermal calorimetry,X-ray diffraction(XRD),and synchronous thermal analysis(TG-DTG).The results show that when the grinding ratio of early strength cement is 80%clinker,5%mixed gypsum,7.5%limestone,7.5%high titanium slag and 2‰calcium formate,the hydration rate of early strength cement surpasses that of P·O42.5R cement during the initial stages,and it has higher abundance of hydration products,which enhances the compactness of the cement matrix and leads to a corresponding improvement in its strength.The early strength cement significantly enhances the 12-hour compressive strength of concrete during low temperature curing.When cured at temperature of 20 to 30℃,the concrete formulated with early strength cement can meet the demolding requirements after a 12-hour curing period,thereby enabling energy-efficient and productive production of prefabricated PC components.