Effects of mineral wool waste in alkali activated-artificial aggregates for high-temperature applications
K.M. Klima, Y. Luo, H.J.H. Brouwers, Qingliang Yu
Abstract
In this study, an alternative utilization route for Mineral Wool Waste (MWW) as a solid precursor for artificial aggregate manufacturing is proposed. The process parameters including alkali activation (Na or K) and curing regimes are investigated. Room and high-temperature (1000 °C) characterizations are performed on the plain aggregates and when incorporated in geopolymer composite. The results reveal that with an optimum pre-curing regime at room temperature for 3 days, artificial aggregates with particle density ranging from 1960 to 2090 kg/m3 and crushing strength of 7.0 to 7.9 MPa can be obtained. The behaviour of aggregates is strongly related to the alkali cation type. The Na-based activator with high viscosity resulted in a more irregular grain shape with a lower particle density and a crushing strength as compared to K-activated aggregates. High crystallinity is observed in K-activated aggregates, causing better thermal stability. The alkali-activated artificial aggregates show a geopolymer-like behaviour in geopolymer composites, which contributes to higher strength development over normal sand aggregate.