Use of High-Fines Limestone Screenings as Aggregate for Controlled Low-Strength Material (CLSM)
SourceBefore the development of performance-enhancing admixtures, flowable fill mixes bled off excess mix water to consolidate after placement. The presence of significant amounts of material finer than 0.075 mm in the aggregate impeded bleeding, and therefore, most specifying agencies limited the percentage allowed to less than ten. New performance-enhancing admixtures limit strength, prevent segregation, and enhance workability by entraining large percentages of stable air bubbles in flowable fill mixtures. Flowable fill mixtures containing these admixtures do not bleed and, therefore, could possibly use aggregates containing greater than 10% finer than 0.075 mm. It was determined that aggregate containing up to 21% finer than 0.075 mm could be used to produce a flowable fill mix meeting National Ready Mixed Concrete Association performance recommendations.