热阻式SMA-13沥青混合料级配优化
Gradation optimization of thermal resistant SMA-13 asphalt mixture

为了研究热阻式SMA-13沥青混合料中耐火碎石最佳掺量,设计了SMA-13沥青混合料配合比方案,即在2.36～4.75 mm集料中,耐火碎石体积掺量为100%,在4.75～9.5 mm集料中,耐火碎石体积掺量分别为20%、40%、60%、80%、100%,在9.5～13.2 mm集料中,耐火碎石体积掺量分别为10%、20%、30%; 研究了耐火碎石掺量对SMA-13沥青混合料路用性能和阻热性的影响规律,提出了耐火碎石最佳掺量,并分析了最佳掺量下热阻式SMA-13沥青混合料路用性能和阻热性能。试验结果表明:与普通SMA-13沥青混合料相比,将2.36～4.75 mm集料全部替换为耐火碎石时,热阻式SMA-13沥青混合料路用性能降低约3%,试件温度降低约1.4 ℃; 4.75～9.5 mm耐火碎石掺量占该粒径普通集料60%时,热阻式SMA-13沥青混合料路用性能降低5%～10%,试件温度降低约5.7 ℃,阻热效果明显,耐火碎石掺量超过60%时,热阻式SMA-13沥青混合料路用性能急剧衰减,阻热效果不明显,掺量为60%～80%时,热阻式SMA-13沥青混合料路用性能降低幅度达到10%～20%,而试件温度降低幅度不超过0.7 ℃; 9.5～13.2 mm耐火碎石掺量占该粒径普通集料10%～20%时,热阻式SMA-13沥青混合料路用性能基本不变,而阻热效果明显,掺量达到20%时,路用性能降低约13%,试件温度降低约7 ℃,耐火碎石掺量超过20%时,路用性能急剧下降,无阻热效果,试件温度增加0.1 ℃; 基于热阻式SMA-13沥青混合料降温效果最佳原则,建议2.36～4.75、4.75～9.5与9.5～13.2 mm耐火碎石掺量分别占同粒径普通集料的100%、60%和20%。
In order to study the optimal dosage of refractory gravel in the thermal resistant SMA-13 asphalt mixture, the mixture proportion schemes weredesigned. In the schemes, the volume content of refractory gravel in the 2.36-4.75 mm ordinary aggregate was 100%, the volume content in the 4.75-9.5 mm ordinary aggregate was 20%, 40%, 60%, 80%, and 100%, respectively, and the volume content in the 9.5-13.2 mm ordinary aggregate was 10%, 20%, and 30%, respectively. The influence laws of refractory gravel content on the road property and heat resistant property of the SMA-13 asphalt mixture were studied, the optimum content of refractory gravel was put forward, and the road performance and thermal resistant performance of the SMA-13 asphalt mixture with this content were analyzed. Research result shows that compared with the ordinary SMA-13 asphalt mixture, when the 2.36-4.75 mm aggregate is entirely replaced by the refractory gravel, the road performance of the thermal resistant SMA-13 asphalt mixture reduces by about 3%, and the temperature of specimen decreases by about 1.4 ℃. When the 4.75-9.5 mm refractory gravel accounts for 60% of the same particle size of ordinary aggregates, the road performance of the thermal resistant SMA-13 asphalt mixture reduces by 5%-10%, the temperature of the specimen decreases by about 5.7 ℃, and the heat resistance effect is obvious. When the content of the 4.75-9.5 mm refractory gravel is more than 60%, the road performance of the thermal resistant SMA-13 asphalt mixture decays rapidly, and the heat resistance effect is not obvious. When the content of the 4.75-9.5 mm refractory gravel is 60%-80%, the road performance of the thermal resistant SMA-13 asphalt mixture reduces by 10%-20%, and the temperature of the specimen decreases by less than 0.7 ℃. When the 9.5-13.2 mm refractory gravel