Development of Durable Green Concrete Exposed to Deicing Chemicals via Synergistic Use of Locally Available Recycled Materials and Multi-Scale Modifiers

2018PDFTech ReportINE/AUTC 17.04INE/CESTiCC 1502INE/CESTiCC 1502AdmixturesBindersDeicing chemicalsDurabilityEnvironmental impactsFly ashHydrationMechanical propertiesRecycled materialsEnvironmentHighwaysMaterialswaste materials recyclingpure fly ashcementitious binderhydration process mechanismsAlaskaUnited StatesUniversity of Alaska Fairbanks. Center for Environmentally Sustainable Transportation in Cold ClimatesXie, NingCui, NaUniversity of Alaska Fairbanks. Center for Environmental Sustainable Transportation in Cold ClimatesWestern Transportation InstituteUnited States. Dept. of TransportationUS Transportation CollectionFrom the economic and social perspectives, the use of waste materials would not be attractive until their costs and quality can satisfy the construction requirements. In this study, a pure fly ash paste (PFAP) was developed in place of ordinary Portland cement paste (OPCP). This PFAP was prepared at room temperature and without direct alkali activation. The samples were prepared using only the as-received class C coal fly ash, water, and a very small amount of borax (Na2B4O7). On average, the PFAP featured 28-d compressive strength of about 36 MPa, and micro-nano hardness and elastic modulus 29% and 5%, higher than the OPCP, respectively. These mechanical and other properties of the PFAP make it a viable \u201cgreen\u201d construction binder suitable for a host of structural and non-structural applications. Advanced characterization of the raw material and PFAP pastes was employed to elucidate the hydration mechanisms of this \u201cgreen\u201d binder. The obtained knowledge sheds light on the role of class C CFA in the hydration process and may benefit the expanded use of various CFAs in cementitious materials