Bond strength assessment asphalt pavement surfacing layers
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Date
2015
Authors
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Journal ISSN
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Publisher
Universiti Teknologi Malaysia
Abstract
A considerable amount of research has been conducted by different researchers to solve poor bonding-related pavement distresses following the increase in real cases reported worldwide. From these studies, several factors which possessed direct effect on pavement interface bonding have been identified. In response to this, a laboratory assessment of the bond strength of the pavement surface layers was carried out for different mixture types, consisting of asphaltic concrete AC 10, stone mastic asphalt SMA 14 and porous asphalt concrete Grading A (PAG A). Other factors include the rapid setting tack coat types (RS1K, RS2K, RS2KL, RS3K, Ralumac), the application rates of the tack coat (none, low, medium, high), and wearing course thickness (35 mm, 50 mm, 65 mm). The work was divided into three major phases. Phase I of the study evaluated the properties of the raw materials used. The determination of the curing time for each of the bitumen emulsion tack coats used was also included. In phase II, modification was done on a shear box to facilitate the direct-shear testing process. In addition, a bitumen pull out tester was also developed to determine the quality of adhesion provided by the tack coat types. Phase III of the study involved directshear test and pull out test. The analysis of variance (ANOVA) revealed that all the tested variables significantly affect pavement interface shear strength. Amongst the mixture types, layer thickness was found to be the most significant factor. The shear resistance for mixture AC 10 and SMA 14 rose with the increasing application rates regardless of tack coat types, except for mixture PAG A. Further analysis suggested that the best layer thickness to be adopted is 50 mm. For mixture AC 10 and SMA 14, the best application rate of 0.55 l/m2 using bitumen emulsion RS2KL was recommended. As for mixture PAG A, the best application rate was 0.76 l/m2 using bitumen emulsion RS3K. The bitumen pull out test results show good correlation of tensile strength and viscosity of the emulsion residue, especially when the application rate is at the lowest. However, there existed no relationship between the tensile strength of bitumen emulsion residue with respect to the resultant interface shear strength obtained. Therefore, it is always important to apply the appropriate quantity of tack coat prior to any paving works at the correct application rate for a given mixture type
Description
Thesis (PhD. (Civil Engineering))
Keywords
Pavements, Asphalt, Pavements—Performance, Pavements, Asphalt concrete—Testing