This book is a state-of-the-art report which documents current knowledge on the properties of fly ash in concrete and the use of fly ash in construction. It includes RILEM Recommendations on fly ash in concrete and a comprehensive bibliography including over 800 references.

Alkali-Aggregate Reaction in Concrete: A World Review is unique in providing authoritative and up to date expert information on the causes and effects of Alkali-Aggregate Reaction (AAR) in concrete structures worldwide. In 1992 a first edition entitled The Alkali-Silica Reaction in Concrete, edited by Professor Narayan Swamy, was published in a first attempt to cover this concrete problem from a global perspective, but the coverage was incomplete. This completely new edition offers a fully updated and more universal coverage of the world situation concerning AAR and includes a wealth of new evidence and research information that has accumulated in the intervening years. Although there are various textbooks offering readers sections that deal with AAR deterioration and damage to concrete, no other single book brings together the views of recognised international experts in the field, and the wealth of scattered research information that is available. It provides a ‘state of the art’ review and deals authoritatively with the mechanisms of AAR, its diagnosis and how to treat concrete affected by AAR. It is illustrated by numerous actual examples from around the world, and comprises specialist contributions provided by senior engineers and scientists from many parts of the world. The book is divided into two distinct but complementary parts. The first five chapters deal with the most recent findings concerning the mechanisms involved in the reaction, methods concerning its diagnosis, testing and evaluation, together with an appraisal of current methods used in its avoidance and in the remediation of affected concrete structures. The second part is divided into eleven chapters covering each region of the world in turn. These chapters have been written by experts with specialist knowledge of AAR in the countries involved and include an authoritative appraisal of the problem and its solution as it affects concrete structures in the region. Such an authoritative compilation of information on AAR has not been attempted previously on this scale and this work is therefore an essential source for practising and research civil engineers, consultant engineers and materials scientists, as well as aggregate and cement producers, designers and concrete suppliers, especially regarding projects outside their own region.

The effects of silica fume and fly ash on reducing the risk of concrete damage due to alkali-silica reaction are presented in this thesis. One silica fume and twenty fly ashes of a wide range of chemical composition were investigated. The effect of the selected materials on expansion when used with high-alkali Portland cement and a siliceous limestone reactive aggregate (Spratt) was evaluated using the concrete prism and the accelerated mortar bar tests. Portland cement pastes and lime/pozzolan blends were prepared using similar combinations of materials used in the expansion tests. These samples were used to study the effects of fly ash and silica fume on the pore solution alkalinity and composition of hydration products. The study showed that the efficiency of fly ash in limiting the risk of deleterious expansion is linked to its efficiency in lowering the pore solution alkalinity. High-calcium and high-alkali fly ashes are generally less effective in this respect compared to low-calcium ash. Silica fume was found to be effective in reducing the pore solution alkalinity at early ages; however, the alkalinity was found to increase at ages later than 28 days. Combinations of moderate levels of silica fume (5%) and high-calcium fly ash (20-30%) were found to be effective in limiting the expansion even after three years. This was attributable to the high capacity of such combinations to achieve and maintain low pore solution alkalinity. The silica fume reduces the pore solution alkalinity at early ages and the fly ash maintained the low alkalinity at later ages. The study showed that, for low and moderate-alkali fly ash, the 14-day expansion in the accelerated mortar bar test could be used to predict the 2-year expansion of concrete prisms. The results from the lime/pozzolan blends confirmed that the hydration products of pozzolan play the dominant role in reducing the pore solution alkalinity of cementitious systems containing pozzolans. The two-year expansion of concrete prisms containing fly ash could be correlated reliably to the alkalis available from the ash as determined by leaching mature paste samples in leaching solution of alkali ion concentration of 0.25 moles per litre.