Comparison of Field Infiltration Test Methods for Permeable Pavement: Towards an Easy and Accurate Method

摘要

Accurate field permeability determination is an important basis for the performance evaluation and maintenance of permeable concrete pavement (PCP). The accuracies of three field permeability-testing methods, namely, constant-head single-ring infiltration (CH-SRI), falling-head single-ring infiltration (FH-SRI), and double-ring infiltration (DRI), are evaluated by comparing with laboratory control results. Factors that influence the accuracy of the tests, including ring size and ponding water head, are investigated. Results showed that CH-SRI and FH-SRI overestimate the infiltration rate due to the unrestricted lateral flow in field PCP permeability tests, especially for partially clogged PCP. The DRI method with an inner ring of 200mm and outer ring of 500mm exhibits good accuracy and is suggested for field PCP permeability test. The existence of initial hydraulic gradient was experimentally and theoretically verified in this study. A 50mm ponding water head in the ring will not affect the accuracy of the tests. A new automatic field double-ring infiltrometer is developed and verified via field tests to overcome the common difficulties in traditional DRI tests. The findings provide an easy and accurate approach for field in situ PCP permeability test.