低热水泥混凝土早龄期强度试验与成熟度分析

Early age strength test and maturity analysis of low heat cement concrete

为定量分析养护温度对低热水泥混凝土早龄期强度的影响,设计3,7,14,28 d 4种龄期和5,20,40,60℃4种养护温度,开展不同养护温度下低热水泥混凝土抗压、劈拉和轴压强度试验。基于成熟度理论,计算了不同工况下试件的成熟度指标,选取对数、指数和双曲线函数形式拟合强度参数与成熟度指标的关系。结果表明:养护温度越高,低热水泥混凝土强度增长越快,但养护温度过高对混凝土后期强度发展不利;Freiesleben和Pedersen提出的F-P等效龄期计算公式、DL/T 5144-2015《水工混凝土施工规范》推荐的D-L等效龄期计算公式和强度-成熟度的双曲线函数形式均能较好地描述强度参数随等效龄期变化的增长规律。研究成果可为大坝施工现场低热水泥混凝土早龄期真实强度性能的预测提供依据。

To analyze the effect of curing temperature on early age strength of low heat cement concrete,the compressive strength,splitting tensile strength and axial compressive strength tests for different test ages(3d,7d,14d,28d)and different constant curing temperatures(5℃,20℃,40℃,60℃)were performed.Based on the maturity theory,the maturity index of each group of specimens were calculated.The logarithmic,exponential and hyperbolic functions were selected to fit the relationship between the strength parameter and the maturity index.The results showed that the higher the curing temperature was,the faster the strength of low heat cement concrete increased,but excessively high curing temperature was detrimental to the later development of concrete strength.The equivalent age equation recommended by Freiesleben and Pedersen,or Chinese specifications for hydraulic concrete construction(DL/T 5144-2015),and strength-maturity hyperbolic function can better describe the growth of strength parameters with the equivalent age.The research results can provide a basis for the prediction of the real early age strength property of low heat cement concrete at dam construction site.