【摘要】 分3批共计24组统计试验考察粉煤灰掺量、试件尺寸以及纤维、骨料性质对混凝土强度统计特性的影响。其中包括立方抗压强度19组,立方体劈裂抗拉强度5组,100mm边长19组,150mm边长5组。试验龄期分别为28d、56d、90d、200d和365d;骨料类型包括页岩两组,普通碎石骨料22组;掺有聚丙烯纤维的共4组。分析表明,龄期增长可以明显降低混凝土强度的离散性;粉煤灰和试件尺寸对混凝土强度离散性的影响没有明显的趋向性。在尺寸对统计平均立方抗压强度影响的试验中,3组中有2组表现为尺寸越大强度越高的特性;尺寸对劈裂抗拉强度统计平均值影响的试验结果均表现出尺寸越大,强度越低的特点。针对24组统计试验数据,进行正态概率分布以及W e ibu ll概率分布假设检验。概率分布假设检验结果表明,W e ibu ll分布与试验强度频率图的右尾端拟合较差。更多还原

【Abstract】 In this paper,24 team statistical tests with different concrete specimen sizes(100mm,150mm),different ages(28d,56d,90d,200d and 365d),different aggregates(shale and ordinary gravel aggregate) and variable admixtures(with and without polypropylene fiber) in 3 groups were tested to analyze the influence of fly ash content,specimen size and characteristics of fiber,aggregate on strength of the concrete,including compressive strength and split tensile strength.Results showed that,long age can significantly reduce the growth of the discrete nature of concrete strength while fly ash volume and specimen size has little impact on the discrete nature of concrete strength.Firstly,two sets in three shows the positive effects of size on the statistical average cube compressive strength.Secondly,the influence of size on the statistical average split tensile strength is negative.In the end,statistical test data of 24 groups were used to verify the normal probability distribution assumption and the Weibull probability distribution of hypothesis.Analyses on the fitting between Weibull distribution curve and frequency plots of the concrete strength show that,the tail of right side is not good.更多还原