Abstract
The purpose of this work is to investigate the difference of bearing capacity of granular base courses which have different grading curves in the range of quality standard. In this work, we used new material and recycled materials produced from cement concrete, asphalt concrete or roof tiles. The CBR value was compared among specimens of a fix material but with a different grading curve which was prepared artificially. The grading curve which gave the maximum CBR value was identical for all the materials. It should be noted that the CBR value of the maximum is more than two times as large as the minimum. So it was found that the artificial grain size preparation improves bearing capacity of granular base courses if the grading curve is not appropriate. We can approximate the grading curve which results maximum bearing capacity by setting n value equal to 0.4 - 0.5 in Talbot's equation.
