Determining Reliability of an Asphalt Mix Design: Case of Marshall Method

Abstract

Asphalt mix design involves a number of tasks culminating in a laboratory estimation of suitable asphalt binder content which is recommended for bulk manufacture of the mix. Generally, the suitable binder content is that which on an average satisfy the specification limits. However, due to inherent material variability, there exists a possibility that all samples (or batches) of a mix designed with a suitable binder content may not always satisfy the specification requirements. The present paper aims to highlight this variability involved in the asphalt mix design process and develop a procedure to estimate the reliability of a particular mix design. This study is based on Indian specifications, where mix design, like in many other countries, is performed in accordance with Marshall method. As an example, experiments have been conducted to determine the reliability of an asphalt concrete mix. Using the same approach, reliability of asphalt mix design for any other mix and mix design procedure can be suitably derived.