Evaluation of the elastic modulus improvement in geocell-reinforced unbound aggregates: Full-scale experimental sections on a highway

This article presents back analyzed results from experimental full-scale field test zones involving unreinforced and geocell-reinforced layers with unbound aggregate infill subjected to in-situ Benkelman Beam test (BBT). The field tests were conducted on experimental test zones during the construction of a new highway. Two types of Unbound Granular Materials (UGM), placed on layers of various thicknesses, were employed in unreinforced and geocell-reinforced pavement zones. Deflection measurements were collected for the different pavement structure layers using the BBT. The main objectives of the testing program were (1) to back calculate the elastic moduli on all test zones in both unreinforced and reinforced layers; (2) to determine the improvement in elastic modulus of the UGM, as quantified by the Modulus Improvement Factor (MIF), which results from geocell reinforcement; (3) to compare the measured MIF with MIF values reported in the literature under similar conditions; and (4) to evaluate the accuracy of available analytical methods to estimate the MIF. The results demonstrated a significant improvement in the elastic modulus of the UGM using geocell reinforcement, with MIF values ranging from 2.6 to 3.3, depending on the fill material. One analytical method used to calculate MIF values was found to have good predictive capability, confirming its potential to the design of pavements with geocell-reinforced layers.