白鹤滩大坝混凝土干燥养护强度与微观结构北大核心CSCD

白鹤滩大坝的建设使用了低热水泥混凝土,为了解它在干燥养护下的特性,本研究探讨了低热水泥混凝土干燥养护下的抗压强度与劈裂抗拉强度发展规律,并通过扫描电镜和压汞法分析微观形貌与孔结构。结果表明:相比标准养护,在干燥养护下低热水泥混凝土28 d抗压强度损失33.3%,劈裂抗拉强度损失31.6%,且水化产物较少、混凝土孔隙率和孔体积会明显增大、孔隙总面积减小,孔径分布以100~1000 nm的大孔为主。本研究表明干燥养护不利于低热水泥混凝土微观结构与强度发展,可为大坝混凝土的养护与强度提供依据。

Dry curing strength and microstructure of concrete of Baihetan dam

The Baihetan dam was built of low-heat cement concrete. To understand its properties under the condition of dry curing, this study focuses on the development of its compressive strength and splitting tensile strength, and presents an analysis on the features of microscopic morphology and pore structure obtained using scanning electron microscope and mercury intrusion methods. Results show that under dry curing, 33.3% of the 28d compressive strength and 31.6% of the splitting tensile strength are lost relative to the standard curing. And dry curing leads to a smaller quantity of hydration products, a significant increase in concrete porosity and pore volume, a decrease in the total area of pores, and the dominance by macropores in a size range of 100 nm to 1000 nm. Thus, this study has verified that dry curing has an adverse effect on the development of microstructure and strength of low-heat cement dam concrete.