Concrete Block Pavement for Low Volume Roads

Concrete block pavement (CBP) is a durable pavement for carrying light as well as heavy loads, and it is being used widely for construction of city streets, parking places, gas stations, container stacking yards, residential areas and low volume roads. This paper presents the findings of a laboratory investigation on structural behaviour of CBP. Plate load and Accelerated Pavement tests were carried out for the evaluation of CBP. Wet Mix Macadam (WMM) has been used as a granular subbase for plate as well as accelerated pavement tests. Plate load test on CBP with the different thickness of WMM without and with the use of jointing sand were carried out and it was found that the reduction in surface deflection was significant for different values of subbase thickness. Pavement deflections taken during the tests were used for determining the structural properties of the pavement. Accelerated tests on 2m wide pavements were also carried out on CBP having WMM subbases in Accelerated Pavement Test facility of the Institute. Falling Weight Deflectometer (FWD) tests were done on the CBP pavements after different repetitions of dual wheel load. The back calculation computer program BACKGA was used for evaluating the moduli of different layers of CBP. It was found that equivalent elastic modulus of concrete block layer increased with increase in subbase thickness and the modulus varied from 700MPa to 3300MPa. Design Charts were developed for low volume roads considering vertical subgrade strain as the criterion for thickness design.