Part 1 – Recommended extensions to Model Code 90 Starting in 1995 as a Joint CEB/FIP Working Group on Lightweight Aggregate Concrete (LWAC), the group was after the merger of CEB and FIP attached to the new fib Commission 8 Concrete. As a background for an extension of the CEB/FIP Model Code 1990 (MC 90) it delivered firstly Bulletin 4. Similarly to what has been done before in the field of High Strength / High Performance Concrete the present guide identifies the lacunae in the existing MC90 and proposes supplementary or alternative solutions to be applied for lightweight aggregate concretes. In order to facilitate its use the report is edited in two columns following the numbering of the CEB-FIP Model Code 1990. The group has given preference to topics of practical importance for LWAC structures, and for which reliable information is available. Justifications of the proposed extensions are to be found in the references to each section. Part 2 – Identification of research needs The technical report identifies the research needs resulting from those clauses of MC 90 which need amendment, and for which more basic research should provide a better understanding of mechanical, physical and chemical processes. Part 3 – Application of lightweight aggregate concrete The state-of-art report documents 33 application examples of projects world-wide. Twenty-eight two-page and five one-page presentations aim to explain the motivation for adopting this technology and report on the design considerations and codes applied, the practical experience during design and construction, the results obtained and the infield performance; for each example references list the literature where more detailed information can be found.

Lightweight aggregate concrete is undergoing something of a renaissance. Although this material has been available for many years, only now is it being used more widely. This book provides a comprehensive review of this growing field from an international perspective.

In spite of the increasing use and demand for lightweight aggregate concrete (LWAC), there is still a lack of adequate explanations to understand the mechanisms responsible for the strength and durability properties of LWAC. This book is written to give an overall picture of LWAC, from the historical background, aggregate production, proportioning and production of concrete, to applications in structures. Physical properties and chemical durability are described in detail. The physical properties include density, strength, shrinkage, and elasticity. Chemical durability includes resistance to acids, chloride ingress, carbonation, and freeze-thaw resistance. Fire resistance is also included, which is seldom considered, but is a very important aspect of the safety of the structure. Microstructure development and its relation to the durability properties of LWAC generally are not highlighted in the literature. The development of bonds, the microstructure with different binder systems, and different types of lightweight aggregates are explained. They show how lightweight aggregate concrete differs from normal weight concrete. The chapters on chloride ingress and freeze-thaw resistance are detailed because of the use of LWAC in offshore construction. The economical aspects of using LWAC are also reviewed. Emphasis is placed on the fact that although the cost of LWAC is high, the total cost of construction has to be considered, including the cost of transport, reinforcement, etc. When these are considered then LWAC becomes cheaper and attractive. The life cycle cost of the concrete is another consideration for calculating long-term savings on maintenance costs.