ACI 304.1R

Abstract

<strong>INTRODUCTION</strong> <br>This report on preplaced aggregate (PA) concrete for structural and mass concrete applications describes practices as developed over many years by engineers and contractors in the successful use of the method; defines the reasons for material requirements that are different from those usually specified for normal concrete; and provides information on equipment, forms, aggregate handling, and grouting procedures. A brief history of the development of the method is given. Photographs with short descriptions for a few major applications are used to illustrate techniques. <br>PA concrete, the finished product, is defined in ACI 116R as "Concrete produced by placing coarse aggregate in a form and later injecting a portland cement-sand grout, usually with admixtures, to fill the voids." Other terms describing the method, used both in America and internationally, include grouted aggregate concrete, injected aggregate concrete, two-stage concrete, Prepakt, Col-Crete, Naturbeton, and Arbeton. PA concrete is particularly useful for underwater construction, placement in areas with closely spaced reinforcement and in cavities where overhead contact is necessary, repairs to concrete and masonry where the replacement is to participate in stress distribution, heavyweight (high-density) concrete, high-lift monolithic sections and, in general, where concrete of low volume change is required.