低水胶比混凝土力学性能及水化物相微观结构

Mechanical properties and hydration phase microstructure of concrete with low water-binder ratio

研究了低水胶比、胶凝材料用量及不同掺合料对超高强混凝土工作性及力学性能的影响规律，并通过SEM分析超高强混凝土微观结构。研究结果表明水胶比为O．15～0．21的混凝土，后期强度达到120～150MPa，其中水胶比为0．15混凝土90d抗压强度达到146．4MPa。粉煤灰在制备高强混凝土时具有显著改善混凝土工作性的特点，但是混凝土后期强度增长较小。超细矿粉制备超高强混凝土时混凝土后期强度优于掺加S95级矿粉的混凝土。SEM分析表明，低水灰比条件下水泥等胶凝材水化生成较多C—S—H凝胶相，微观结构致密均匀，未水化水泥颗粒在硬化浆体中主要起到填充作用和微骨料作用。

The water-binder ratio, the amount of cementitious material and mineral admixtures effect on the mechanical property and microstructure of concrete was studied.The results show the water-cement ratio of 0.15-0.21 concrete compressive strength between 120-150 MPa in the late, and the water-bindert ratio of 0.15 reached 146.4 MPa compressive strength of concrete at 90 days.Fly ash has significantly improved workability characteristics, but smaller increase late strength of concrete when preparing high-strength concrete. Add superfine slag powder compared to the $95 slag powder for the development of late strength is more better.SEM analysis showed that under the conditions of low water-binder ratio of cement hydration produce more C-S-H gel phase.Hydration of cement paste microstruc- ture is dense and uniform.Unhydrated cement micro-aggregate partieles primary role is filled pores in the hardened cement paste.