粉煤灰级配碎石的施工和易性及其评价指标

Working performance and evaluation index of fly-ash graded aggregates

为提高级配碎石的强度和骨架-密实型级配的施工和易性,并给出级配碎石的工作性能评价指标和方法.在级配碎石集料中掺加适量的粉煤灰,利用粉煤灰的保水性和振动液化性来提高级配碎石的施工和易性.通过性能试验可知,粉煤灰的加入可改善级配碎石的保水性,延长有效碾压时间,相同压实条件下,固体体积率提高5%,增加了基层的密实程度,同时,抗离析性能增强.通过级配碎石自由堆积试验中堆积直径和堆积高度的变化规律,定义了评价级配碎石施工和易性的指标,并提出了评价标准.试验分析和试验路的修建表明离析系数可以评价级配碎石的施工和易性,粉煤灰的加入提高了级配碎石的工作性能和强度,粉煤灰的掺量存在最佳用量.

In order to improve the strength and construction workability of framework-dense graded aggregate, working performance evaluation index and method of the graded aggregate are put forward. Results of performance test show that the proper addition of fly-ash in graded aggregate can improve the water retention of graded aggregate, and the solid volume rate is increased by 5% , which enhances the performance of segregation resistance. According to the change regularity of height and diameter of the graded aggregates in free pile test, the segregation coefficient to evaluate the graded aggregates segregation is defined, and the evaluation criterion is put forward. Comparison between the analysis of test and the building of test road indicates that the segregation coefficient can evaluate the working performance of graded aggregates. The proper addition of fly-ash improves the working performance and strength of graded aggregates.