Using large-scale test to investigate the surface strain of cement/asphalt concrete

It is unclear that how much the small-scale tests can reflect the actual situation of pavement. The full-scale test is a convincing way but costly. Therefore, large-scale test is a balance of reliability and cost. This study proposed a large-scale test to study the surface strain of cement concrete, cement stabilized macadam and asphalt concrete. The parallelism and reproducibility of tests were analyzed. The effect of loading value and location on radial strain and hoop strain were studied. The results show that a round-pie sample with a 20 cm thickness and a 100 cm diameter was effective as a large-scale sample on evaluating the effect of loading on surface strain. The measured strain data had a good parallelism and reproducibility. The surface radial strains of the cement stabilized macadam and asphalt concrete samples presented mechanical response characteristic points including maximum compressive strain point, tensile-compressive demarcation point, and tensile strain peak point, but the cement concrete sample didn't show them. With the increase of load level, the strain values of the three pavement samples increased gradually, but the overall variation trends of strains and the locations of mechanical response characteristic points remained unchanged. For asphalt pavement, the region close to the loading was a compressive zone, but the region away from the loading was a tensile zone.