ACI 211.9R-2018 Guide to Selecting Proportions for Pumpable Concrete

ACI 211.9R-2018 Guide to Selecting Proportions for Pumpable Concrete. The fneness modulus (FM) of fne aggregate meeting ASTM C33/C33M grading specifcations will fall between 2.30 and 3.10. Pumpability of mixtures is generally improved with a decrease in the FM (fner fne aggregate). The FM alone, without stipulations for particle distribution, might not produce satisfactory results. Larger quantities of coarse aggregate may be used with a lower FM, as shown in Table 3.2.2. This resource is recommended as a guide to the amount of coarse aggregate to combine with fne aggregate of diferent FM values. Fine aggregate for concrete can be obtained from natural deposits or manufactured by crushing coarser materials to the desired sizes. The pumping characteristics of concrete produced with diferent sources of fne aggregate can vary. The FM is a good indicator for determining the acceptability of natural or crushed fne aggregate for the mixture. Small quantities of mineral fllers (for example, crusher dust and limestone fller), supplementary cementitious materials, or both, are often useful in correcting defciencies in the fner sizes. Successful pumping experience indicates that combining materials from separate sources often brings satisfactory results. Blending as little as 5 percent natural sand could render concrete mixtures with certain manufactured sands pumpable. Similarly, small additions (typically 5 to 10 percent) of manufactured fnes may improve the pumpability of concrete mixtures containing natural sands. 4.1—General The information provided in this guideline applies to portland cement (ASTM C150/C150M; ASTM C595/ C595M; ASTM C1157/C1157M). The determination of the cementitious materials content for a pumpable mixture follows many of the same basic principles used for any concrete. The use of extra quantities of cementitious materials as the only solution to the correction of pumping difculties is shortsighted and uneconomical. It is far more desirable to frst correct any defciencies in the aggregate grading, especially in the fne aggregate fraction. With well-graded coarse and fne aggregates properly combined, the cement factors for pump mixtures will closely parallel those used in other concrete, as explained in ACI 211.1 and ACI 211.2. Much has been written about the use of alternative materials as a substitution for cement, the scope of which is beyond this guide. For further discussions on the use of these materials in concrete, refer to ASTM C618, ASTM C989/ C989M, and ASTM C1240. In terms of the efect they have on concrete pumping: a) Fly ash (ASTM C618)—Pumpability is improved and...