Fatigue performance of gussasphalt concrete made from modified AH-70# asphalt

Use of modified asphalts in preparation of gussasphalt (GA) concrete could reduce the demand of lake asphalt or low-grade straight asphalt, but the fatigue performance still needs to be studied further. Using a composite-modified asphalt (CMA) consisted of AH-70# asphalt, lake asphalt, SBS modifier and other agents, this work investigated the effect of mixing temperature, oil-stone ratio of mixture and strain level of loading on the fatigue performance of the resulting concretes. It is shown that when CMA was used, the mixing temperature should be elevated to 230-240 °C and oil-stone ratio increased to 8.5 in order to meet the requirement of laying construction process. The number of cycles Nf to fatigue failure was up to 0.5 million or more under the strain level of 800 × 10−6. This work finally compared the fatigue performance of the GA concrete made from CMA with those of other asphalt concretes and presented the error analysis of testing results using an existing assessment method, from which it was concluded that a new assessment method should be proposed for the evaluation of the fatigue performance of CMA concretes.