热养护对MgO激发碱矿渣材料抗压强度与微结构的影响

Effect of thermal curing on compressive strength and microstructure of MgO activated alkali-slag materials

为改善MgO激发碱矿渣材料(MASM)的早期力学性能,采用早期热养护(6 h)研究了养护温度对MASM抗压强度的影响,分析MASM水化产物及微观形貌。研究结果表明:热养护可有效提高MSAM的1 d抗压强度,随养护温度的提高,MASM的1 d抗压强度先增高后降低,提升幅度为59%~183%。适当的热养护可加速MgO水化成为Mg(OH)_(2),并促使形成密实的微结构,有利于形成更强的胶结结构。然而,养护温度过高使得C-S-H凝胶原位沉积在矿渣颗粒的表面,抑制矿渣的溶解,从而导致MASM后期水化不充分。最终,确定50℃组为最优组,其1 d抗压强度即可达到对照组3 d水平。

In order to improve the early mechanical properties of MgO activated slag materials(MASM),it studied the effect of curing temperature on the compressive strength of MASM using early thermal curing(6 h),and analyzed the hydration products and microstructure of MASM.The results show that thermal curing effectively enhances the 1 d compressive strength of MSAM.With the increase of curing temperature,the compressive strengths of MASM increase first and then decrease on 1d,with an improvement range of 59%~183%.Proper thermal curing not only accelerates the formation of Mg(OH)_(2) but also makes microstructure dense,which is conducive to the formation of stronger cementitious structure.However,C-S-H gelsare in-situ deposited on the surface of slag particles due to the high curing temperature,which inhibited the dissolution of slag,thereby causing inadequate hydration of MASM in the later stage.Finally,50 ℃is determinedas the optimal temperature since the compressive strength of MASA on 1 d can reach the level of the control group on 3 d.