氧化钙对硅酸盐水泥-铝酸盐水泥-硫酸钙体系低温水化性能的影响

Influence of Calcium Oxide on the Hydration Performance of Portland Cement-Aluminate Cement-Gypsum Ternary System at Low Temperature

石灰(Ca O)作为胶凝材料的一种,在溶于水后迅速消解而释放出大量热量,可用于提高硅酸盐水泥-铝酸盐水泥-石膏三元体系的温度,可能会促进其低温下的水化性能。本文通过向三元体系中分别掺入2.0%、3.5%、5.0%及6.5%的Ca O,研究体系在不同温度(20℃、15℃、10℃和5℃)下的凝结时间和养护至不同龄期(1 d、3 d、7 d和28 d)下胶砂试件的强度和限制膨胀率,并采用X-射线衍射(XRD)和扫描电镜(SEM)对体系水化产物的组成和形貌予以了测试和分析。研究结果表明:由于Ca O对钙矾石(AFt)生成的延迟作用,致使体系的1 d强度较低;随着龄期的延长,该延迟作用消失,水化进程加快,强度增长幅度较大。

As a kind of rapid digestion and high value binder material,calcium oxide can be used to improve the temperature of Portland cement-aluminate cement-gypsum ternary system,and may promote the hydration performance of the ternary system under lower temperature. In this paper,a new binder system was prepared by adding calcium oxide at dosage of 2. 0%,3. 5%,5. 0%,6. 5% to the above ternary system,the setting time under different temperature of 20 ℃,15 ℃,10 ℃,5 ℃,as well as mortar specimens strength and restrained expansion rate at different temperatures of 20 ℃,15 ℃,10 ℃,5 ℃ and different ages of 1 d,3 d,7 d,28 d. Finally,the composition and the morphology of the quaternary gelling hydration products were tested by X- ray diffraction and scanning electron microscopy.The results show that with the dosage of calcium oxide increased,the delayed effect of calcium oxide on ettringite generated,which results in lower early strength（ 1 d）,but as age goes on,since delay effect disappears,hydration process accelerated leading to greater strength.