Accelerated pavement testing of low-volume paved roads with geocell reinforcement

Abstract

Four lanes of pavement test sections were constructed at the Infrastructure System Laboratory (CISL) of Kansas State University. Three of the four lanes had 75-mm geocell-reinforced bases and 25-mm cover of three different in-fill materials; crushed limestone, AB-3; quarry by-products; and Recycled Asphalt Pavement (RAP).The fourth test lanewas the control section consisting of 300-mm crushed stone (AB-3) base.The sections were paved with a 50-mm Superpave Hot-Mix Asphalt (HMA) layer. All sections were instrumented to measure the strains at the bottom of the HMA layer and stresses on top of the subgrade. The sections were loaded with 50,000 and 70,000 repetitions of an 80-kN single axle load of the Accelerated Pavement Testing (APT) machine. The failure rut depth was 12.5 mm. All sections except the control section had this rut depth by 10,000 repetitions. The calculated and measured responses show that on three test sections, stresses on top of the subgrade exceeded the unconfined compressive strength of the soil. The test sections were redesigned and reconstructed. The redesigned sections consisted of 100-mm geocell- reinforced bases, 50-mm cover, and an HMA layer of 100 mm. The same infill materials were used in the test sections. The control lane had a depth of 200 mm. These sections were also instrumented. All sections carried 1,200,000 repetitions of the 80-kN single axle loads with rut depths not exceeding 10 mm. Based on these results, a mechanistic-empirical design methodology for low-volume paved roads with geocell-reinforced bases is being developed.