ASR Potential and Mitigation Measures for Wyoming Aggregates

作者：Fertig Ryan; Kimble Margaret; Jones Angela; Tanner Jennifer Eisenhauer^*

来源：Journal of Materials in Civil Engineering, 2017, 29(9): 04017112.

DOI：10.1061/(ASCE)MT.1943-5533.0001977

Discovered in the 1940s, alkali-silica reaction (ASR) causes undesired expansions in concrete. If unmitigated, ASR may cause premature deterioration. Since its discovery, researchers have sought an economical and rapid method for detecting the potential for and presence of ASR. ASR is a global concrete durability problem with a complexity that demands respect. Over the past 15 years, the Wyoming Department of Transportation (WYDOT) has addressed this problem by subjecting aggregates to the accelerated mortar bar test (AMBT) before using them in new concrete. This study combines several classification test methods with an outdoor exposure site (OES) to most accurately classify Wyoming aggregates. Of the aggregate sources studied, 25% are nonreactive, 50% are moderately reactive, one is highly reactive, and the remaining source falls on the border of moderately and highly reactive. The test methods generally agree, and a trend between the aggregate composition and expansion is noted. Recommendations for expansion limits compared to exposure blocks with mixed coarse and fine aggregates are introduced. Wyoming, located in the center of North America, produces subbituminous coal that may not be suitable to mitigate ASR. Because fly ashes are highly dependent on the parent coal, the widespread use of Wyoming coal for power generation in the United States means that fly ashes similar to the ones used in this study are likely to be available for use in concrete in many areas of the country. This emphasizes the need for more detailed chemical studies and predictive tools to determine the suitability of pozzolans and particular aggregate sources. Also, it was found that even the most expansive aggregates can be effectively mitigated using a semilocal fly ash.

• 出版日期2017-9