Alkali silica reactions, cement, Coarse aggregates, Concrete pavements, Fly ash, Gravel, Kansas Department of Transportation, Sand, Slag
The Kansas Department of Transportation (KDOT) has controlled harmful alkali-silica reactions (ASR) through testing and selective use of sand and gravel aggregates for more than 70 years. ASR can also be controlled through the addition of a non-reactive coarse aggregate ÛÏsweetenerÛ and by the judicious use of selected supplementary cementitious materials. Current KDOT specifications allow the use of sands and gravels that may otherwise undergo ASR with the addition of a ÛÏsweetenerÛ aggregate. Using one or more supplementary cementitious materials (SCMs) in a concrete may accelerate or hinder alkali-silica reactions, depending on the alkali and silica contents of the SCM and the aggregates used. Class C fly ash may aggravate ASR and until 2009 was not approved for use in Kansas pavements. The purpose of this project is to evaluate the effect of combining portland cement with Class C fly ash and slag cement on the physical properties, alkali-silica reactivity (ASR), and durability of concrete containing reactive fine aggregate and limestone coarse aggregate.