Non-bloated synthetic aggregate concrete

Abstract

Increasing use of non-bloated synthetic aggregate has stimulated research in its manufacture and application. Engineering design criteria are based on a knowledge of the properties of materials, and this study attempts to add a modicum of information about synthetic aggregate to the present incomplete supply. This dissertation presents the results of a study of the clay, aggregate, and concrete, which are raw material, product, and its application, respectively. The clay was studied by chemical analysis, size, fractionation, x-ray diffraction, and electron microscopy. The reasons for bloating and non-bloating of clay are discussed. The aggregate was subjected to a variety of tests, some standard and some innovative. Concrete was tested for strength, chemical stability, and physical durability. A number of conclusions are presented, but perhaps the foremost conclusion is that it is very difficult to make incontrovertible statements about clay and synthetic aggregates. These materials do not yield their secrets readily. Results of study and testing of 35 batches of concrete made from 17 aggregates made from 5 clays are presented. The range of the data shows the great variety and complexity which must be dealt with in an investigation of this type. The following conclusions were drawn: 1. Non-bloated synthetic aggregate is suitable for making concrete. 2. For concrete of the same strength, more cement is required than with natural dense aggregate. 3. New methods of evaluating this relatively new material need to be developed. 4. The ability of non-bloated synthetic aggregate concrete to withstand cycles of freezing and thawing is greatly improved by drying the concrete.