基于OGFC-13沥青混合料高温稳定性的级配优化

Gradation Optimization Based On High Temperature Stability of OGFC-13 Asphalt Mixture

为提高OGFC-13(Open Graded Friction Course-13)沥青混合料高温稳定性能,考虑矿料不同通过率所形成的骨架强度对其影响,参考CBR(California bearing ratio)试验以及单轴贯入试验对拟定的10组玄武岩矿料进行骨架贯入试验。以最大贯入压力(F)及贯入能量(E;)评价骨架强度,分析矿料通过率对骨架强度的影响,以此对OGFC-13沥青混合料的级配进行优化来提高高温稳定性。基于摩尔-库伦理论对OGFC-13沥青混合料进行单轴贯入试验、无侧限抗压强度试验计算沥青混合料的粘聚力值(c)和内摩擦角(φ)值,以此评价混合料抗剪强度。结果表明:在级配设计中,2.36mm通过率增大骨架强度降低;4.75mm通过率为20%时2.36mm、9.5mm破碎率最小;9.5mm通过率为60%时骨架结构强度最好。级配优化后的沥青混合料φ值较高,表现出良好的高温稳定性。

In order to improve the high temperature stability of Open Graded Friction Course-13(OGFC-13),considering the influence of skeleton strength formed by different passing rates of mineral aggregate,skeleton penetration tests were carried out on 10 groups of basalt mineral aggregate with reference to California Bearing Ratio(CBR)and uniaxial penetration test.To optimize the gradation of OGFC-13 asphalt mixture and improve its high temperature stability,skeleton strength was evaluated by maximum penetration pressure(F)and penetration energy(E_p),and the influence of mineral aggregate passing rate on skeleton strength was analyzed.Based on Mohr-Coulomb theory,the uniaxial penetration test and unconfined compressive strength test are carried out to calculate the cohesive force(c)and internal friction angle(φ)of OGFC-13,so as to evaluate the shear strength.The results indicate that the 2.36 mm passing rate increases and the skeleton strength decreases,the passing rate of 4.75 mm is 20% the crushing rate of 2.36 mm and 9.5 mm is the smallest,the passing rate of 9.5 mm is 60%,the strength of skeleton structure is the best in the gradation design.After grading optimization,theφvalue of asphalt mixture is higher,showing good high temperature stability.