Repeatability and reproducibility of micro-surfacing mixture design tests and effect of total aggregates surface areas on the test results

Abstract

The first part of this study evaluates the repeatability of the International Slurry Surfacing Association (ISSA) mixture design tests. Consistency of test results between two laboratories (MTQ and LCMB) was evaluated. Aggregate gradation and sample preparation method were varied, and the responses for various ISSA mix design test for micro-surfacing were examined. The repeatability of four ISSA mix design tests for micro-surfacing was computed. To do this, the micro-surfacing mixtures were prepared by four technicians in two separate laboratories in Quebec. The modified cohesion test, the wet track abrasion test, the loaded wheel test, and the resistance to compaction test were evaluated in this study. The effect of sample preparation method using aggregate splitting and sieve analysis on consistency of mixture design test results was also evaluated. It was observed that employing sieve analysis method for micro-surfacing mixture preparation yields better consistency in test responses. For the second part of this study, the role of aggregate gradation, and their total surface area on cohesion, resistance to abrasion, and resistance to permanent deformation of micro-surfacing mixtures was studied. Two different type III applications of micro-surfacing mixtures, which are used as rut-fill materials in high traffic area, were selected to determine the effects of aggregate total surface area on micro-surfacing mix design test responses. It was found that the micro-surfacing mixtures prepared using aggregate gradation with more fine aggregates have higher resistance to rutting, bleeding, abrasion and moisture susceptibility.