RESEARCH AND TECHNO-ECONOMIC EVALUATION: USES OF LIMESTONE BYPRODUCTS

Abstract

The stockpiling and disposal of byproduct fines produced by the coarse aggregate industry in Florida is one of the most important problems facing the industry today. Both coarse and fine fractions of byproduct fines represent highly under-utilized resources suitable to applications in the construction market. This research had three goals: (1) to estimate the current and future quantity and quality of byproduct resources at selected sites in the state; (2) to characterize the physical and mineralogical characteristics of these byproduct fines presently stockpiled and sold commercially in both state and national markets; and (3) to identify potential economic uses for these fine materials, increase productivity, and extend the life of an important natural resource based on temporal and spatial variations in composition. The first goal was accomplished using a questionnaire and visits to selected producers identified by the Florida Department of Transportation (FDOT) to have significant inventories and/or be future producers of fines and screenings. Although the quantity of coarse fines produced annually exceeds that of the fine category, producers tend to sell approximately 78% of the coarse category as compared to 34% of the fine category. As a result, producers identified the need for more research and marketing directed at developing products for the fine category of fines. The second goal was accomplished through an investigation of the particle size distribution (gradation), moisture content, and mineralogy of byproduct fines collected from coarse aggregate producers identified by the FDOT. The data collected can be used as input in the development of specifications and test procedures used to evaluate and approve fines for various applications. The third goal was accomplished through a review of the literature available on the use of byproduct fines, evaluation of economic data, and testing of processing methods on fines from three sites identified by the FDOT and representing different lithologies.