二灰碎石基层材料的合理结合料质量分数

Optimal volume content of binder in lime-fly-ash-stabilized aggregate

在二灰碎石最优级配的基础上,根据集料不同密实状态下的空隙率变化结合料的体积分数,通过力学性能、干缩、温缩性能试验,研究结合料质量分数的变化对路用性能的影响,并运用灰色关联决策对不同结合料质量分数下二灰碎石路用性能进行了综合评定。结果表明:当石灰与粉煤灰的质量分数达到21.5%时,二灰碎石28 d抗压强度、劈裂强度和抗压模量达到最大值;二灰碎石7 d龄期的干缩应变随着结合料质量分数的减少而减小;二灰碎石7 d龄期的总平均温缩系数(60℃^-30℃)和低温平均温缩系数(10℃^-30℃)随着结合料质量分数的减少而减小,而高温平均温缩系数(60℃~10℃)呈增大趋势;二灰结合料存在一个最佳体积分数,即当二灰结合料的体积分数等于集料的松散状态下空隙率时,其路用综合性能才能达到最优。

On the basis of the optimal gradation of lime-fly-ash-stabilized aggregate and through the experiments of mechanical performance, temperature-shrinkage and dry-shrinkage properties, this paper analyzes the influence of different binder mass content, which is determined by vacuole rate of aggregate in different dense states, on road performance. With gray related strategy, this paper evaluates the road performance of lime-fly-ash-stabilized aggregate under different binder mass content comprehensively. By analyzing the tests, the optimal unconfirmed compression strength,cleavage strength and modulus of resilience（28 d） can be gained when the mass content of lime-fly-ash is 21. 5%. After 7 d maintenance under standard conditions, the dry shrinkage tests indicate that the strain decreases when the content of lime and fly-ash is cut down. Furthermore, the temperature shrinkage coefficients, including the whole average coefficient, at the range of 60 ℃--30 ℃, and low temperature average coefficient, at the range of 10 ℃--30 ℃, reduce with the decrease of the content of lime and fly-ash. But the coefficient of temperature, at the range of 60 ℃- 10 ℃, is quite the reverse. The results of evaluation show that the comprehensive road performance of lime-fly-ash-stabilized aggregate is optimal when the volume of binder equals to the vacuole rate of aggregate in incompact states, which is an optimal binder content in the lime-fly-ash-stabilized aggregate. 5 tabs, 5 figs, 11 refs.