Laboratory Study of Large Stone Asphalt Paving mixtures

摘要

A summary of NCHRP Project 4-18, "Design and Evaluation of Large Stone Mixtures," is provided. The objectives of the study were to evaluate the effectiveness of currently used large stone asphalt paving mixtures (LSMs) in resisting rutting, develop a mixture design procedure for LSMs, and provide guidance on quality assurance testing and constructibility of LSMs. State highway agencies were surveyed to identify successful mixture design procedures, quality assurance test procedures and criteria, materials specifications, and construction practices for LSMs. Cores from several LSM pavemetns and control (conventional) pavements in 5 states were tested. LSM specimens were compacted and tested in the laboratory to evaluate their rut resistance. Tests included SHRP repeated simple shear at constant height, creep/recovery, axial compression to failure, indirect tension, resilient modulus, and consistency of extracted binders. Findings from the laboratory tests were used in developing mixture design procedures and mixture analysis systems to ensure that LSMs will provide the desired performance under the given conditions of traffic and environment. Full-scale rutting tests of 3 LSM mixtures were conducted to evaluate their relative ability to resist rutting and to evaluate the mixture design procedure developed in this program. Construction guidelines to aid in mixing, placing, and compacting LSMs were prepared.