以粉煤灰、废玻璃粉、矿粉和煤矸石粉作为掺合料等质量取代20%的水泥,碎石、破碎卵石和混合骨料作为粗骨料制备混凝土,来研究不同掺合料、粗骨料对鲍罗米公式回归系数的影响,对最小二乘法的残差进行无偏性、同方差性、无序列相关性、解释变量与随机误差相互独立性和正太分布性检验,发现其不满足同方差性假定,故采用加权最小二乘法回归计算鲍罗米公式回归系数。结果表明,混凝土抗压强度的方差与胶水比的平方成正比或与混凝土抗压强度的平方成正比;每种粗骨料和不同掺合料组合的鲍罗米公式回归系数均存在较大差异。粗骨料与掺合料发生耦合作用,相互影响着鲍罗米公式回归系数。
In order to investigate the effect on the regression coefficients in Bowromi formula of different admixtures and coarse aggregate,the research used fly ash and waste glass powder,mineral powder and powdered coal gangue as admixture respectively to replace 20% cement according to the same quality together with gravel, broken pebble and combined aggregate as coarse aggregate for preparation of concrete.The residual of the least squares was tested about the unbiasedness,homoscedasticity,no serial correlation, explanatory variables and random error mutual independence as well as the normal distribution.These tests showed that it did not meet the assumption of homoscedasticity.Therefore,the regression coefficients in Bowromi formula was obtained by using the weighted least squares.The result shows that the variance of the compressive strength of concrete is proportional to the square of cement/water ratio or the square of the compressive strength of concrete.Different types of coarse aggregate and combination of admixtures have great difference on the regression coefficients in Bowromi formula.The coupling action produced by coarse aggregate and admixture mutually influence the re- gression coefficients in Bowromi formula.