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Evaluation of New Asphalt Concrete Job Mix Formula Specifications

项目名称：	Evaluation of New Asphalt Concrete Job Mix Formula Specifications
摘要：	The North Carolina Department of Transportation (NCDOT) has recently modified the asphalt mixture design procedures in part, to increase the asphalt content and address observed cracking issues with asphalt mixtures. These changes have reduced the number of asphalt mixture types, changed compaction levels and the volumetric limits for some mixtures, and adjusted how recycled materials are considered. Given the complexity of the interactions between material parameters, the procedural changes do not guarantee that the resultant asphalt mixture designs have actually achieved the intended goal of improved durability. The proposed study will investigate how these recent changes have affected asphalt mixture designs with respect to composition and performance. A research study is needed because an understanding of how procedural changes like the ones enacted by the NCDOT affect the durability of asphalt mixtures under real world conditions does not exist. This research is also needed because; (1) mixture designs in North Carolina are performed by contractors and submitted to NCDOT for approval, which limits the control that the NCDOT has over how contractors interpret and use the mixture design procedures and (2) currently, the NCDOT does not incorporate cracking tests into their mixture design or mixture verification process; therefore, they must rely heavily on volumetric composition to ensure that durable mixtures are designed and used. With respect to these needs, the proposed research plan will achieve two objectives; (1) Compare and compile detailed comparisons of NCDOT approved asphalt concrete mixtures that were designed under the current and previous design procedures; and (2) Evaluate the impact of these changes on pavement performance. Depending on the precise findings of this research, the primary outcome will either be confirmation that the updated NCDOT asphalt mixture design procedures have resulted in mixtures with improved durability or suggested additional changes that could achieve this goal. These outcomes can be used by the Materials and Test Unit of the NCDOT to improve asphalt mixture design, which will result in cost savings.
状态：	Active
资金：	91309
资助组织：	North Carolina Department of Transportation
项目负责人：	Kadibhai, Mustan A
执行机构：	North Carolina State University
开始时间：	20190801
预计完成日期：	20200731
主题领域：	Design；Highways；Materials；Pavements