ACI 211.9R-18 Guide to Selecting Proportions for Pumpable Concrete

ACI 211.9R-18 Guide to Selecting Proportions for Pumpable Concrete. 4.1 —General The information provided in this guideline applies to portland cement (ASTM C150/CI5OM: ASTM C595/ C595M; ASTM CI 157/Cl 157M). 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 ofeementitious materials as the only solution to the correction of pumping difficulties is shortsighted and uneconomical. It is far more desirable to fIrst correct any deficiencies in the aggregate grading. especially in the fine aggregate fraction. With well-graded coarse and tine aggregates properly combined, the cement factors for pump mixtures will closely parallel those used in other concrete, as explained in ACI 211 I 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, ASThI C99/ C989M. and ASTM (‘1240. In terms of the effect they have on concrete pumping: a) Fly ash (ASTM C618)—Pumpability is improved and Waler requirements are decreased due to the spherical- shaped particles acting as ball bearings, thereby providing a lubricant effect and reducing frictional losses during the pumping process b) Slag cement (ASTM (‘989/C989M)—Pumpabilily is generally improved due to having lower specifIc gravity than cement, resulting in higher paste volume for a given cementitious content c) Silica fume (ASTM C1240)—Pumpability is improved; however, water requirements are increased due to its liner particle size than cement yielding higher surface area required to be coated There are three criteria that affect pumpability: I) n/cm: 2) mortar volume; and 3) cementilious materials content. For effective and etlIcient pumping, the target ranges given in Table 4.la may be used as a guideline to evaluate mixture pumpability. However, it should be noted that although these target values are applicable for most applications, there may be some cases that would fall outside of these recommended ranges and still achieve the desired pumpability. Therefore. these values may be taken as a starting point to evaluate pumpability and, if necessary, may be adjusted to accommodate a specific condition, Values shown in Table 4.lb are taken from a practical example of a pumpable mixture specification.ACI 211.9R pdf download.