مجله جنگل ایران (May 2017)
Evaluation of mechanical properties and strength of river and mine aggregate for pavement and maintenance of forest roads
Abstract
The difference between subgrade and expected bearing capacity is compensated with pavement. Usually, due to budget constraints, local aggregate material is used for road construction and maintenance activities. Before using these materials, conducting mechanical tests is necessary, but unfortunately, these tests are neglected in forest management plans which may cause future problems for the road. In this study, mechanical tests were conducted on two source aggregate samples and the results were compared with standard values. The results showed that river gravel was better matched with standard particle size distribution but had low fine-grained particles than standard. Also the uniformity coefficient and coefficient of gradation for riverine mix represent a wide range of particle size and size distribution between D10 and D60. The results of Los Angeles tests for riverine and mine mix were 29.38 and 23.09%, respectively and broken face content was for riverine and mine mix was 94.73 and 63.26% respectively. The results showed that abrasion and broken face content were in the standard range but maximum dry density and CBR were lower than standard. Regarding available budget, some modifications like particle distribution modification or stabilization could resolve the disadvantages of the aggregate. If improvement measurements are neglected, the consequences and damages to the road will be expected, a phenomenon that many roads have due to lack of knowledge about the properties of used aggregate material.
