The use of high-volume fly ash concretes can be challenging for high-early strength applications, such as in precast construction, largely due... Show moreThe use of high-volume fly ash concretes can be challenging for high-early strength applications, such as in precast construction, largely due to potential delays in strength gain resulting from relatively lower heats of hydration of the underlying binder formulations. Considering that the use of higher levels of available fresh or landfilled fly ash as a replacement for traditional ordinary Portland cement (OPC) could result in more sustainable mix designs, a framework to develop novel, high-volume fly ash mixes with optimized dosages of commercial grade gypsum and accelerating admixtures to enhance early-age strength performance. Early-age mechanical properties such as compressive strength, modulus of rupture, and modulus of elasticity were evaluated starting within 24 hours of specimen preparation. Experimental test results were then characterized and subsequently analyzed relative to current design provisions to highlight the best performing trial mixes (with respect to the early-age strength target) and cases where current design provisions are either unconservative or overly-conservative with respect to the test data. Additionally, thermal properties of concrete produced with fly ash were tested with two different curing environments, along with using code equations to determine if high volume fly ash provides a higher thermal resistance compared to OPC concrete. Wrapping up cementitious replacement with non-proprietary ultra high-performance concrete (UHPC) for transportation structures. Then reproducing mixtures to ensure target compressive strength values could be reached. Followed by increasing batch size to a larger quantity using a large mixer to create full-size specimens. Show less
