水泥稳定碎石基层强度及影响因素相关性分析

Correlation Analysis of Strength and Influencing Factors of Cement Stabilized Macadam Base

为明确施工中水泥稳定碎石基层强度影响因素的关联性,依托实际工程分析了双拌缸拌和工艺下水泥稳定碎石基层水泥剂量、混合料级配、压实度和厚度等因素的变异性.建立了7 d抗压强度与施工前场和后场的九个影响因素变异性(0~4.75、>4.75~9.5、>9.5~19、>19~26.5 mm、水泥剂量、厚度、含水率、干密度、压实度)的相关性分析和主要影响因素的通径分析.分析结果表明:基层混合料0.6 mm以下筛孔变异系数整体较大,其余强度影响因素大致服从正态类分布.0~4.75 mm粒组用量X2、19~26.5 mm粒组用量X4、水泥剂量X5、含水率X7、干密度X8、压实度X9的变异性与强度Y的变异性显著相关,并且这6个因素的变异性显著决定了强度变异性的94.17%,强度Y与显著影响因素X间的线性回归方程Y=-164.601+0.299X2+0.163X4+1.147X5+1.576X7+28.408X8+0.804X9.(R=0.9704),其中,对强度变异性的直接影响中干密度变异性决定作用最大,压实度变异性决定作用最小.因此,建议生产中通过优化级配和碾压工艺、控制离析、注意水和水泥的用量来降低强度变异性.

In order to clarify the relevance of influencing factors on the strength of cement stabilized macadam base during construction,the variability of cement dosage,mixture gradation,compaction degree and thickness of cement stabilized macadam base under double mixing tank mixing process was analyzed based on practical engineering.The correlation analysis of 7 d compressive strength and the variability of 9 influencing factors(0~4.75 mm,4.75~9.5 mm,9.5~19 mm,19~26.5 mm,cement dosage,thickness,water content,dry density and compactness)and the path analysis of main influencing factors were established.The analysis results show that the coefficient of variation of the sieve holes below 0.6 mm of the base course mixture is relatively large as a whole,and the other strength influencing factors generally obey the normal distribution.The variability of 0~4.75 mm granule dosage X2,19~26.5 mm granule dosage X4,cement dosage X5,water content X7,dry density X8 and compactness X9 are significantly related to the variability of strength Y,and the variability of these six factors significantly determines the strength variability of 94.17%.Among them,dry density variability plays the most important role in determining strength variability,while compactness variability plays the least role.Therefore,it is suggested to reduce the strength variability by optimizing gradation and rolling process,controlling segregation and paying attention to the amount of water and cement.