Reliability of Microsurfacing Mix Subjected to Variation in Aggregate Gradation

Abstract

Reliability analysis describes the probability of the pavement satisfying the performance criteria throughout its design life. Assigning reliability during the design stage is vital for the proper planning of maintenance and rehabilitation activities. In this respect, this study evaluates the reliability of microsurfacing mix subjected to variations in aggregate gradation. A total of 10 different combinations of aggregate gradation were selected where the initial five combinations were based on the specification limits and the other five were randomly generated using Monte Carlo simulation. The performance was assessed in relation to cohesion, abrasion loss, rutting, and bleeding. Results indicated a significant variation in test results even when the aggregate gradation was varied within tolerance limits. The primary factors contributing to the variability were the total surface area of aggregates and the mineral filler content in the mix. Reliability analysis of the test parameters was conducted through the specified limits of each test. It was found that the reliability of each test parameter was more than 90%. However, the overall reliability, including all the test parameters, was 73%. The reliability of the microsurfacing mix meeting all the performance requirements increased to 90% when the aggregate gradation tending to a lower specification limit was excluded. Further, the individual reliability of each test parameter was more than 95%. Thus, to ensure higher reliability, microsurfacing mix with a lower total surface area and a lower mineral filler content should be avoided during the production stage of microsurfacing mix.