Engineered Limestone Tailor Milled To Scc Mix Designs
- Written by CP Staff
Pittsburgh-based Carmeuse Lime & Stone first announced the availability of Premiacal, an engineered limestone with fineness characteristics especially suited to self consolidating concrete (SCC) mixes Û in North America at National Precast Concrete Association's Precast Show in Houston.
During the mid-February event, company staff noted the product is well established among concrete customers of its European operations Û with over 400 precast and ready-mixed customers to date on the continent Û and that Premiacal testing is under way with North American precast and ready mixed producers. Premiacal is already a big commercial success in Europe, says David Berg, Carmeuse marketing manager-milled limestone and the man recently appointed to spearhead the engineered limestone introduction in the U.S. and Canada. At this point we're beginning the process of piggybacking on that success. However, the market dynamics are not the same, as concrete-grade fly ash is more readily available in North America than it is in Europe.
Berg said he expected a commercial precaster to commit sometime in the early summer to using Premiacal in its primary SCC mix design. The product can be used in many different applications, including manholes, utility vaults, etc., explains Berg, who is based in Pittsburgh. At this time, several companies are evaluating and working with us on testing Premiacal.
Through proprietary grinding and gradation (Carmeuse estimates that an average particle of Premiacal is one-tenth the size of a cement particle), Premiacal achieves improved particle packing that allows for portland cement substitution at rates up to 15 percent by weight. Premiacal also plays a part in accelerating the hydration reaction of cement. The engineered limestone imparts workability, density, segregation resistance and green strength development properties SCC users target for precast and cast-in-place conditions. The product is also said to aid in demolding and improved pumpability. SCC mixes have become more popular in recent years because of strength improvements and cost savings, due to shorter construction periods, no need for vibration equipment, and labor savings.
The company is quick to point out that since limestone is a natural, environmentally friendly and chemically stable product, its usage is harmless to the environment and provides long-term durability for building and construction.
Premiacal is manufactured at seven milled limestone plants, serving the North American market. Carmeuse Lime & Stone is the North American business of Belgium's Carmeuse Group. Û www.carmeusena.com