Sources: Brigham Young University Department of Civil and Environmental Engineering, Provo, Utah; Concrete Masonry Association of California and Nevada (CMACN); CP staff
To boost market prospects for masonry walls of high recycled materials content, CMACN is supporting an investigation to a) confirm that California Building Code-required strength is maintained in grouts where portland cement is substituted with Class F fly ash at 45–65 percent and Class F fly ash + GGBF slag at 65–85 percent; and, b) observe how prism units containing such grouts behave with Type M, S and N mortars. Under the direction of Professor Dr. Fernando Fonseca, BYU Department of Civil and Environmental Engineering staff is preparing to test 180-day grout strengths, following measurement at seven, 28 and 56 days.
Utah Masonry Council masons and BYU students assembled 600 prisms earlier this year, using 8 x 8 half blocks supplied by Oldcastle Architectural; fly ash from Headwaters Construction Materials; and, NewCem GGBF slag from Lafarge Cement. Mix designs for the high supplementary cementitious material grouts mirror those of 2009-10 CMACN research to validate code-compliant alternatives to portland cement-only formulations. Findings from it have supported widespread specification in California of high fly ash or fly ash/slag grouts, all found to consistently develop code-required 2,000 psi strength.
The CMACN-BYU research is funded by the National Concrete Masonry Association Education and Research Foundation. At the NCMA Mid-Year Meeting (August 24–28, Vancouver, B.C.), Foundation trustees are set to review a California Polytechnic State University, San Luis Obispo, proposal to investigate self-consolidating grouts designed primarily with high SCM.