Proportioning with Ground Limestone and Mineral Filler-Fine Limestone Additions to Improve the Performance of (High Volume Fly Ash) Concretes (PDF)

Fine Limestone Additions to Improve the Performance of (High Volume Fly Ash) Concretes (PDF)

Pdf Summary

This document presents research focused on reducing cement content in concrete mixtures for improved sustainability. The team from NIST and FHWA/SES Group explores alternatives to traditional cement by employing binary and ternary binder blends, particularly highlighting the role of ground limestone powder and fly ash.<br /><br />To reduce cement content, they suggest increasing aggregate content up to 75% and using supplementary cementitious materials (SCMs) or blends with ground limestone. Such strategies could reduce cement consumption by up to 60%. The study emphasizes that using finer limestone helps reduce setting times in concrete mixtures, particularly those with Class C fly ash, by accelerating the hydration process.<br /><br />The research further delves into the effectiveness of high-volume fly ash (HVFA) concretes when combined with limestone. They have identified a successful mixture ratio of 3:1 fly ash to limestone, achieving both strength and reduced environmental impact. The study highlights that by replacing cement with ground limestone and adjusting water-to-cement ratios, it is possible to maintain or enhance the concrete's performance, while substantial reductions in cement are achieved.<br /><br />In tests, mixture proportions varying limestone fineness and fly ash content were experimented with to assess their impact on strength, setting times, resistivity, and cost. The findings suggest that the addition of limestone powder improves setting time, increases strength, and enables higher resistivity, thus projecting longer service life for concrete structures.<br /><br />The study concludes by emphasizing the importance of cost-performance optimization, especially in incorporating high-range water reducers. It acknowledges the collaborative efforts of various researchers and suppliers in advancing these findings and mentions a range of publications for further, in-depth reading on these innovations in sustainable concrete technologies.

Keywords

sustainable concrete

cement reduction

NIST

FHWA/SES Group

binary binder blends

ternary binder blends

ground limestone powder

fly ash

high-volume fly ash

concrete performance