Evaluation of Effect of Heat-Adhesive Emulsions for Tack Coats with Shear Test: From the Road Research Laboratory of Barcelona

Abstract

The use of conventional emulsions for tack coats can cause problems as they frequently stick to the tires of construction vehicles. Consequently the bond between the asphalt layers is inadequate. The importance of tack coats in the performance of the pavement means that bituminous emulsions are constantly being improved. Recently, new types of emulsions have been developed from very low penetration bitumen that contains no flux. They are known as "heat-adhesive" emulsions and they are resistant to construction vehicles. The purpose of this study is to analyze the effect of different heat-adhesive emulsions and to verify their performance in service, in comparison with the response of a conventional emulsion. For this reason a new shear test -the LCB test-has been developed in the Road Research Laboratory of the Technical University of Catalonia. This test is carried out at different temperatures, both on laboratory specimens and on cores extracted from recently constructed pavements, where the same emulsions and dosages have been used. The application of the LCB test has shown that the performance of the different heat-adhesive emulsions mainly depends on the characteristics of the base bitumen and the kind of modifier used. At low temperatures, heat-adhesive emulsions reach, in general terms, lower shear resistances than conventional emulsions; however, at intermediate temperatures there are heatadhesives emulsions with both higher and lower strengths than those of the conventional emulsions.

[Retracted] Application of Wireless Communication in Experimental Research of the Interface Bonding Condition between Asphalt Layers by Tensile Testing

“…The interface bonding condition between asphalt layers is one of the most important factors that affect the performance of the pavement structure and have attracted more and more attention to study the bonding testing during recent years. This leads to the development of different test devices and corresponding parameters to characterize the bonding properties in numerous papers and scientific contribution, such as layer parallel direct shear test, wedge splitting test, torque test, and pull-off test [1][2][3][4]. In China, extensive technical specifications and rules of tack coat for asphalt layers have been set up but the standard test method for evaluating the quality of layer bonding does not exist.…”

Ensaio de cisalhamento de interface com vistas a camadas de pavimentos

“…O Ensaio de Cisalhamento LCB (Laboratorio de Caminos de Barcelona) (Figura 1-D) é um ensaio de cisalhamento com uma con iguração diferente daqueles anteriores, baseado em treŝ pontos. Miró et al (2006) explicam que para o ensaio é empregado um corpo-de-prova cilıńdrico, com diâmetro de 101,6 mm, disposto como viga sobre dois apoios afastados 200 mm entre si. Para que ocorra o cisalhamento uma força é aplicada na vertical de modo a gerar um deslocamento constante de 1,27 mm/min, cerca de 5 mm da seção de corte, para ser desprezıvel o efeito do momento letor gerado.…”

Test methods and influential factors for analysis of bonding between bituminous pavement layers

“…Surface roughness and texture Several studies have included the surface roughness and texture as influential factors. Canestrari et al [49], Recasens et al [50,51], Tashman et al [45], Mohammad et al [39], Santagata et al [52], Leng et al [43] and Liu et al [37] realized that interface condition has direct influence on fatigue resistance. Higher strength is obtained for milled surface, with a minimal effect of the absence of tack coat applied, whereas this tack coat's absence severely decreases the strength for the non-milled sections [45].…”

“…Partl et al [54], Romanoschi et al [27], Mohammad et al [15], West et al [21], Recasens et al [50,51], Canestrari et al [49], Piber et al [33], Chen et al [46], Du et al [38] and Diakhate et al [29] found that temperature is an important factor. They found that temperature has a high influence on bond strength [38] and that the modulus obtained from the curve slope, the maximum shear and the coefficient of friction before the break are influenced by temperature [28].…”