Chapter 30—Lightweight Concrete and Aggregates

Abstract

Both “lightweight concrete” and “lightweight aggregate” are general terms which include a wide variety of products and are frequently subject to varying definitions. Concrete lighter in weight than that usually obtained with “normal weight” aggregates (gravel, air-cooled blast-furnace slag, and crushed stone) may be produced by several methods: 1. Lightweight aggregate concrete, which is comparable to conventional concrete except for the use of lightweight materials as all or part of the aggregate. 2. Cellular or foam concrete, where the light weight is caused primarily by inclusion of a large amount of air or gas, usually 25 percent or more. A suitable foam or foaming agent is combined with cement and water, either with or without other ingredients such as sand or pozzolanic fines. 3. No fines or “popcorn” concrete, with the light weight produced by high air contents or specially graded aggregates having little or no fine material or both. Either lightweight or normal weight aggregates may be used.