ACI 211.7R-20 Guide for Proportioning Concrete Mixtures with Ground Calcium Carbonate and Other Mineral Fillers.
This guide provides recommendations for proportioning normalweight concrete with ground calcium carbonate (6CC) and dust-of-fracture aggregate mineral fillers (AMF). II also provides background information on these materials, techniques for their characterization, and their effects on concrete properties: however, it is not intended to be a comprehensive literature review and the reader should conduct trial batches to evaluate specifIc materials being used and to confirm concrete performance. It is intended to supplement ACI 211.1 and is for materials meeting ASTM C1797. Proportioning methods for 6CC and for dust-offracture AMF are discussed separately.
Mineral filler is defined as a finely divided mineral product at least 65 percent of which passes the No. 200(75 run) sieve. This delinilion includes the materials addressed herein:
namely. 6CC as specified in ASTM Cl 797 and dust-of-fracture AMF from quarried rock as specified in either ASTM Cl 797 orASTM C33.C33M.
6CC, also known as ground limestone, is a manufactured fine product composed primarily of calcium carbonate and with particles sized within narrow ranges. 6CC has been used successfully in concrete in Europe for decades, either added to the concrete mixture separately from the cement or interground with clinker to form portland-limestone cement (European Committee for Standardization 2009).
Dust-of-fracture AMF is rock dust created during production, processing, or handling of quarried stone. Such materials can vary in mineral composition and other physical characteristics, depending on the parent stone from which they are derived, the crushing process, and the washing or air separation process. Dust-of-fracture AMF can be provided as a dry bulk powder meeting ASTM C1797 or as part of manuf,ictured sand as described in ASTM C33/C33M.
This guide does not address precipitated calcium carbonate or material finer than the No. 200 (75 rim) sieve in natural sand, nor the use of limestone as a cement ingredient, which is addressed in ASTM Cl50/CISOM. C595C595M. and Cl 157. Although 6CC typically falls within the defInition of AMF, it is dealt with separately in this guide. It is manufactured under controlled conditions to be a consistent product. Dust-of-fracture AMF consisting primarily of calcium carbonate is not considered 6CC.
The aggregate suspension mixture proportioning method described in Ad 211 .6T has been used to proportion concrete with 6CC and dust-of-fracture AME.
The use of both 6CC and dust-of-fracture AMF can improve the sustainability of concrete production. 6CC has a lower embodied energy and lower CO2 emission during its production than an equivalent mass of portland cement. Dust-of-fracture AMF is typically a by-product of the blasting and crushing of aggregate. This guide can facilitate the use of 6CC and aggregate mineral fIllers as a means of optimizing the powder content of concrete, thereby increasing sustainability.ACI 211.7R pdf download.