粗集料棱角性对水稳河滩料强度和干缩特性影响的试验研究

Experimental Study on Influences of Angularity of Coarse Aggregates on Strength and Dry-shrinkage Characteristic of Cement Stabilized Beach Materials

针对粗集料棱角性对水稳混合料路用性能(强度和干缩特性)的影响展开试验研究。试验结果表明,粗集料不宜含有较多的浑圆状颗粒和针片状颗粒,其松装空隙率宜控制在43%～45%,振装空隙率宜控制在41%～43%。此外,全部破碎颗粒中混入不超过20%的浑圆状颗粒可以有效减少松(振)装空隙率和针片状含量,对提高混合料无侧限抗压强度有利;含有不超过20%浑圆状颗粒的粗集料与全部破碎的粗集料相比,其劈裂强度相差不大。干缩试验表明,拐点失水率与合成矿料骨架空隙率有一定关系,骨架空隙越大,拐点失水率也越大;当粗集料中含有较多的浑圆状颗粒时,其干缩系数拐点失水率相对较小。

This paper develops experimental study on influences of angularity of coarse aggregates on road performance（strength and dry-shrinkage characteristic） of cement stabilized mixtures.The results of experiment indicate that coarse aggregates should not contain many round,needle-like and flaky particles,the loose-packed voidage should be controlled in the range of 43%～45% and the vibratory-packed voidage in the range of 41%～43%.In addition,mixture of no more than 20% round particles in all crushed particles can effectively reduce loose（vibratory）-packed voidage and contents of needle-like and flaky particles,in favor of improving unconfined compressive strength of mixtures;in comparison with fully crushed coarse aggregates,the splitting strength of coarse aggregates with content of round particles no more than 20% is slightly different.The dry-shrinkage test shows that the knee-point rate of water loss is certainly related to framework voidage of composite mineral materials,the larger the framework voidage,the higher the knee-point rate of water loss;when coarse aggregates contain more round particles,the knee-point rate of water loss of its dry-shrinkage coefficient is relatively small.