详情

Validation of Gyratory Mix Design in Iowa Phase II

项目名称：	Validation of Gyratory Mix Design in Iowa Phase II
摘要：	As a result of the Phase I Study, the N specifications were changed in October 2016. In addition to the mix design changes, the Iowa DOT has implemented new asphalt binder grading criteria. Phase II is primarily a validation study of the new mix design specifications. The first objective of Phase II is to evaluate performance of the field mixes produced with the 2016 specifications to ensure performance expectations are being met for rutting, moisture susceptibility and low temperature cracking; both loose mix and cores will be sampled for subsequent testing. The second objective is to evaluate the new mix design specifications in terms of performance and constructability. A mix design analysis for each of the new ESAL levels using the source aggregates and binder from the field construction projects will be re-evaluated in mixture design. The N design will be validated using traditional mix design procedures by varying asphalt content to compact to 4% air voids. Measuring strength in the design process will directly correlate N design with performance tests. The third objective of the study entails performance testing of each mix at the optimum binder content in a given N design level using such tests as the dynamic modulus, Hamburg wheel track device, and disk-shaped compact tension to evaluate the stiffness, rutting moisture susceptibility and resistance to low temperature cracking. The results of this study will provide detailed information either verifying current N design levels in Iowa or give recommendations on how N design can be improved based on performance testing data and N design correlations with field density. The results will also show how changes to N design will impact rutting and mixture stiffness as well as predicted pavement performance. Phase II will be conducted as a laboratory study with the goal of addressing the mix design process and identifying how changes in N design will influence performance over a pavements lifetime. Tasks include: Task 1 - selection of projects, collection of materials and cores, and volumetrics evaluation. Task 2 - Evaluation of optimum asphalt contents for different N design values at three traffic levels. Task 3 - Comparison of new and old specifications through performance testing and analysis. Task 4 - Analysis and evaluation of performance test results in Pavement-ME. Task 5 - Development of final report.
状态：	Active
资金：	250000
资助组织：	Iowa Department of Transportation
管理组织：	Iowa State University, Ames
项目负责人：	Goetz, Vanessa
执行机构：	Iowa State University, Ames
主要研究人员：	Williams, Chris
开始时间：	20180315
预计完成日期：	20200630
实际结束时间：	0