Reactivity of municipal solid waste incineration ashes as a supplementary cementitious material

The high carbon and energy footprint of cement calls for substitution by supplementary cementitious materials (SCMs), and for various waste streams or by-products, cementitious products have been identified as an effective sink. The variability of the composition of these SCMs makes it necessary to identify a fast and reliable test to predict concrete strength and facilitate their utilization. There are some conventional reactivity tests such as the Modified Chapelle test and Frattini test, that measure reactivity based on indicators such as consumption of calcium hydroxide in accelerated conditions. Furthermore, new tests called R3-tests, applicable for SCMs from various sources, have been developed recently and are currently tested within RILEM TC-267 TRM. Municipal Solid Waste Incineration (MSWI) ash is identified as a potential SCM, the composition of which varies with time and location. In the current research two size fractions of MSWI ash were selected, and conventional and R3 reactivity tests were conducted on this material. This paper reports the results of all reactivity tests and compares them with the strength development of mortar bars with 25% Portland cement replacement by MSWI ash