Polanco, Hannah1; Fonseca, Fernando S.2 and Eggett, Dennis L.3
1 Graduate Student, Department of Civil and Environmental Engineering, Brigham Young University, Provo, UT, 84602, USA, hannahpolanco@gmail.com
2 Associate Professor, Department of Civil and Environmental Engineering, Brigham Young University, Provo, UT, 84602, USA, fonseca@byu.edu
3 Associate Research Professor, Department of Statistics, Brigham Young University, Provo, UT, 84602, USA, theegg@byu.edu
ABSTRACT
The research presented herein intends to streamline the use of lightweight aggregate in masonry grout by developing a design standard for lightweight masonry grout. Lightweight concrete has been in use for decades—including in concrete masonry units—but lightweight aggregate has yet to be widely utilized in masonry grout. For example, the US masonry code does not include lightweight masonry grout in its provisions. The parameters explored in the experimental program include minimum grout compressive strength requirements, slump requirements, and aggregate proportions comparable to those of current normal weight grout standards. Relationships between these variables were analyzed to develop acceptable ranges for a tentative lightweight grout mix design standard. Preliminary findings showed that the aggregate proportion range for normal weight grout, when applied to lightweight grout, provided well over the required minimum grout compressive strength. Therefore, the range of aggregate proportion was increased, which resulted in compressive strengths closer to the minimum grout strength requirement. In addition, the slump range was slightly widened from that of the normal weight grout standard due to the absorptive nature of the lightweight aggregate. One of the main challenges of using lightweight aggregate is to achieve and maintain a saturated surface dry condition for the aggregate. Thus, carefully measuring, controlling and adjusting for moisture in the lightweight aggregates is critical and the most challenging part of the mix design process.
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