Setting behavior and mechanical properties of geopolymers from fly ash and real construction waste

Abstract

Sustainability is becoming an increasingly important factor in the development of new building materials. In terms of the sustainability of concrete components, the biggest challenge is the high energy consumption and associated greenhouse gas emissions in the production of Portland cement. A common strategy used by the construction industry to improve sustainability is to use residuals to develop lower-emission geopolymer concretes that eliminate high-emission cement-based concretes. Because construction and demolition waste, at 3 trillion tons per year worldwide, also represents an environmental risk, this work will investigate the suitability of geopolymers based on real construction waste. In the course of the investigations, the manufactured geopolymer samples are examined for the material parameters relevant to building materials, namely compressive strength, flexural strength, raw density, total porosity, and thermal conductivity. The setting behavior and the forming structures are investigated by infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. The present study is intended to contribute to the development of a suitable recycling strategy for the material recycling of construction waste in novel geopolymer material.