Abstract

Urban pavements for buses need to resist high traffic demands without regular invasive maintenance interventions that affect the pavement clients. Although Jointed Plain Concrete Pavements (JPCPs) is a sustainable alternative that can provide these requirements, but sealing the joints and keeping them sealed for 10 years costing up to 45% more than Unsealed Joints (UnJs). In UnJs, a saw-cut of 2 mm impede the introduction of coarse material in the joint. And when the amount of fines in the underlying base layer is limited the water cannot drag fines, so no pumping, and no production of joint faulting for this concept. The objective of the present paper is to compare the performance of sealed and unsealed joints in Bus Corridors (BCs). For that, new field measurements are made in 90 Sealed Joints (SJs) of 2 BCs at Santiago, the capital city of Chile. In addition, 30 SJs of an adjacent lane dedicated to private transportation but with similar traffic demands that a BC is included. In total, measurements are made in 120 SJs at Santiago city. The results of these auscultations are compared with previous field evidence of the performance of UnJs at BCs with similar traffic demands at the same city, i.e. same climatic conditions as well. Furthermore, the experience of 50 years of the Wisconsin Department of Transportation (WisDOT) of USA with sealed and unsealed joints is also considered. For the analysed conditions, the results of the comparison are coincident with the experience of WisDOT, i.e. the joint seals do not enhance the performance of the JPCPs and then they are not justifying their costs of construction and maintenance. In fact, in the measurements of Santiago city there are more sealed than unsealed joints affected by spalling. And in one section of SJs even joint faulting was detected. Although the level of spalling is very low (average 40 mm) the joints will require maintenance interventions in order to avoid further joint deteriorations with the increasing of traffic in time. In effect, as typical adhesive failures are present as well in the SJs and these j oints were constructed wide enough to receive the seal there is space available for the introduction of incompressible materials and water that can produce further joint spalling and joint faulting. On the contrary these maintenance interventions are not required in the UnJs. Even when it is recommended to continue the follow-up in the BCs, the comparisons were made until 5 million accumulated equivalent single axle loads. This traffic demand represents the ones of the entire life-cycle of other pavements in the city and even other BCs. Then UnJs are a cost-effective alternative to optimize the design of urban JPCPs. In effect WisDOT has reported savings of 6,000,000 US dollars annually due to the use of UnJs.