Experimental Study on Mechanical and Degradation Characteristics of Crushed Rock Aggregate

You are here: Homepage > Search

Experimental Study on Mechanical and Degradation Characteristics of Crushed Rock Aggregate

Wang, Pengcheng / Liu, Jiankun / Tian, Zeye / Li, Xu

Particle breakage of crushed rock aggregate (CRA), especially uniformly graded CRA, can always be observed under different loading conditions. The degradation process will greatly influence the mechanical response. A large-scale direct shear system was used to investigate the mechanical and degradation behavior of five gradations of CRA (four uniformly graded and one well graded). The index of Hardin’s relative breakage potential was used to evaluate the breakage state of the four gradations of the uniformly graded CRA. The relationship between particle breakage and mechanical behavior was also evaluated. The results indicate that the shear strength of CRA increased obviously with normal stress; volumetric dilation was always observed after the initial contraction; smaller normal stress always led to larger dilation as well as a lower amount of contraction; and the shear strength and compression displacement under the same normal stress increased with particle size. Larger vertical pressure always produced more breakage, and the largest content increment always happened in the secondary sieve size, followed by the smaller sieve size. Compared with the breakage index, the relative breakage potential was better for evaluating the degradation of the uniformly graded CRA; the degradation resulted in a decrease in the peak stress ratio, peak friction angle, peak compression displacement, and peak dilation angle, which all can be linearly fitted with the relative breakage potential.