Steyn, Wynand Jacobus Van der MerweBriedenhann, R.2012-10-122012-10-122012-04Steyn, WJ & Briedenhann, R 2012, 'Evaluation of microclimate effects on surfacing seal performance', Journal of Preformance of Constructed Facilities, vol. 26, no. 2, pp. 138-144.0887-3828 (print)1943-5509 (online)10.1061/(ASCE)CF.1943-5509.0000203http://hdl.handle.net/2263/20139Surfacing seals consist of a combination of bitumen and aggregate, and are used to provide an all-weather surfacing to protect underlying layers and provide safe access to vehicles traveling on a road. Analysis of a number of sections in Gauteng, South Africa, has shown that surfacing seals lost a large proportion of their aggregate where the road was crossed by a bridge. As all original properties of the seal components as well as the traffic on the road were similar, it was deduced that the micro-climate where the road traveled underneath the bridge should have caused this localized failure condition. In this paper the phenomenon is investigated through analysis of the micro-climate underneath the bridge, the material properties of the surfacing seal, and the combined effect of these factors on the performance of the seal. It is shown that the micro-climate can affect the performance of an otherwise suitable surfacing seal to such an extent that the performance of the seal is severely compromised. A procedure for the analysis of potential micro-climate effects is described in the paper.en© American Society of Civil EngineersSurfacing sealsMicro-climateAggregate lossPostprint Article