Effective use of ground waste expanded perlite as green supplementary cementitious material in eco-friendly alkali activated slag composites

摘要

The production of alkali activated slag composites (AASCs) generally requires a large amount of slag, and waste expanded perlite (WEP) is a type of industrial waste that can be used as green supplementary cementitious material (SCM) in the building industry. In this study, the feasibility of using ground WEP as a sustainable replacement for slag in AASCs was evaluated. The process of hydration, mechanical properties, and ecological and economic performance of the AASCs with ground WEP (WEP-AASCs) were investigated in this study. The results showed that the 28-day compressive strength of WEP-AASCs at 10, 30, and 50 vol% WEP decreased by 2.4 MPa (4%), 7.3 MPa (12%), and 9.4 MPa (16%), respectively, compared to AASCs without WEP. In addition, both the heat of reaction and reaction peak of WEP-AASCs by thermogravimetric analysis decreased with the increasing additions of ground WEP. Combined with the X-ray diffraction (XRD) and scanning electron microscope (SEM) of WEP-AASCs, it was found that the addition of ground WEP did not change the reaction products in the AASCs. Based on the economic and ecological analyses, reductions in cost (6-19%), embodied energy (5-24%), and embodied CO2 emissions (3.2-16%) can be achieved, compared to AASCs without ground WEP. Therefore, WEP is suitable for use as SCM in AASCs, and presents promising applications based on the identified performance and sustainability. (C) 2018 Elsevier Ltd. All rights reserved.