详情

Alkali-Silica Reaction Mitigation using Alternative Supplementary Cementitious Materials

项目名称：	Alkali-Silica Reaction Mitigation using Alternative Supplementary Cementitious Materials
摘要：	New Mexico contains several aggregate sources that are extremely susceptible to alkalisilica reaction (ASR). To mediate ASR, the New Mexico Department of Transportation (NMDOT) requires a minimum of 20% class F fly ash (by mass of cement) in nearly all concrete produced for their projects. Since class F fly ash has become difficult to procure and future availability is uncertain, NMDOT is considering alternative supplementary cementitious materials (SCMs) that could be used in place of class F fly ash. This project will assess two SCMs being considered for widespread acceptance by NMDOT and builds on work performed during a Year 3 Tran-SET project to investigate a natural pozzolan mined near Espanola, NM for use with extremely reactive fine aggregates. This new project will focus on utilizing the natural pozzolan (pumicite) as well as a metakaolin product with a broad range of reactive aggregates. NMDOT has limited data for mixture proportions and durability properties (such as ASR mitigation) of concrete produced with these SCMs. Therefore, they are unable to confidently accept the materials for use in concrete produced for NMDOT projects, even if class F fly ash is not available. The specific focus of this project is to assess ASR mitigation capabilities of the alternative SCMs when used in combinations with several crushed coarse aggregate sources so that general guidelines that can be developed to minimize the use of the SCMs (based on aggregate reactivity) to prolong availability of SCM sources and improve sustainability. This project will begin with a comprehensive literature review to identify the most important properties and characteristics of SCMs, especially metakaolin and natural pozzolans, in terms of their influence on ASR and concrete durability. For the experimental work, a suite of mortar mixtures will be proportioned with cementitious materials combinations that include the pumicite and metakaolin as well as control mixtures that contain either fly ash or no SCMs. ASR mortar bar tests will be conducted using eight aggregate sources and SCM contents that range from 0 to 30%. Effectiveness of the SCMs will be assessed by comparing their performances with results from the control mixtures. Cementitious materials combinations that produce acceptable ASR results will be used to produce 10 concrete mixtures that will be tested for slump, air content, compressive strength, and flexural strength to ensure that the mixtures provide adequate workability and strength, and then subjected to durability tests to assess their chloride permeability, resistance to freezing and thawing, and shrinkage characteristics. The primary purpose of the concrete testing is to evaluate whether the mixtures have workability, strength, and durability properties that are comparable to mixtures containing only class F fly ash. The implementation phase of the project includes documenting and disseminating the results of the research in a final report for the project, publication of journal and conference papers, and presentations at conferences. The New Mexico State University (NMSU) research team is led by the PI, Professor Craig Newtson, who has more than 20 years of concrete related research experience, has had projects totaling more than $2,400,000 in funding, and has published more than 85 research papers.
状态：	Active
资金：	106000
资助组织：	Office of the Assistant Secretary for Research and Technology
管理组织：	Transportation Consortium of South-Central States (Tran-SET)
项目负责人：	Mousa, Momen R
执行机构：	New Mexico State University, Las Cruces
主要研究人员：	Newtson, Craig
开始时间：	20220401
主题领域：	Bridges and other structures；Highways；Maintenance and Preservation；Materials；Pavements