การใช้ซ้ำวัสดุแอสฟัลต์คอนกรีตผิวทางเดิมเป็นวัสดุทดแทนพื้นทางหินคลุกผสมซีเมนต์สำหรับงานก่อสร้างถนน

Abstract

This research studied the utilization of the reclaimed asphalt concrete pavement, which is a by- product of road maintenance while milling the damaged-road surface, as a replace material of cement modified crushed rock base for road construction. This is one of the efficient waste utilization and it also reduces the use of crushed rock, which is an important natural resource. Moreover, crushed rock mining activities have huge impacts on the environment. From the results, it can be note that the reclaimed asphalt concrete pavement can be used as a replace material of cement modified crushed rock base. In this experiment, the optimum ratio of the added cement and aggregate material was investigated by comparing with the Department of Highways Standards, Thailand. The aggregate materials used in the experiments were the mixture of the reclaimed asphalt concrete pavement and crushed rock at different ratio, including 0:100, 40:60, 50:50, 60:40 and 70:30, respectively. This study shows that the higher amount of added cement was required while the higher proportional of reclaimed asphalt concrete pavement had been used. The percentage by weight of the optimum added cement were 1.20, 1.99, 2.34, 2.45 and 2.55, respectively, for the ratio of 0:100, 40:60, 50:50, 60:40 and 70:30, respectively. However, very high amount of added cement was required when the sole reclaimed asphalt concrete pavement had been used (100.0). For the cost evaluation, it was found that using of the reclaimed asphalt concrete pavement for cement modified crushed rock base could reduce the investment cost for road construction. The road construction cost was reduced in accordance with the quantity of reclaimed asphalt concrete pavement. Using the mixture of the reclaimed asphalt concrete pavement and crushed rock at 40:60, 50:50, 60:40 and 70:30, respectively, can reduce the cost of road construction and the reduction costs were equal to 365.12, 423.19, 506.17 and 589.03 THB per cubic meter, respectively. While the construction cost was 1,198.61 THB per cubic meter when using sole crushed rock as aggregate materials for in-plant construction. In addition, the results found that the investment cost of in-plant construction was cheaper than in-place construction.