Demolition Waste Potential for Completely Cement-Free Binders

Abstract

Due to renovation and fighting in the world, a huge accumulation of construction and demolition waste is formed. These materials are effectively used as aggregates, but there is very little information about the use of scrap concrete to create cementless binders. The purpose of the work is to be a comprehensive study of the composition and properties of concrete wastes of various fractions with the aim of their rational use as cementless binders. The scientific novelty lies in the fact that the nature of the processes of structure formation of a cementless binder based on sandy fractions of the screening of fragments of destroyed buildings and structures, as a complex polyfunctional system, has been theoretically substantiated and experimentally confirmed. Different percentages of non-hydrated clinker minerals in concrete scrap were determined. In the smallest fraction (less than 0.16 mm), more than 20% of alite and belite are present. Waste of the old cement paste is more susceptible to crushing compared to the large aggregate embedded in it, therefore, particles of the old cement paste and fine aggregate predominate in the finer fractions of the waste. Comprehensive microstructural studies have been carried out on the possibility of using concrete scrap as a completely cementless binder using scanning electron microscopy, X-ray diffraction analysis, and differential thermal analysis. It has been established that for cementless samples prepared from the smallest fractions (less than 0.315 mm), the compressive strength is 1.5–2 times higher than for samples from larger fractions. This is due to the increased content of clinker minerals in their composition. The compressive strength of the cementless binder after 28 days (7.8 MPa), as well as the early compressive strength at the age of 1 day after steaming (5.9 MPa), make it possible to effectively use these materials for enclosing building structures.

Performance evaluation of fiber-reinforced concrete produced with steel fibers extracted from waste tire

“…Then, waste and disposal stage may lead to a huge threat to the environment and high cost. Thus, instead of disposal of waste, recycling, and reuse of them in many industries are viable solutions (Karalar et al, 2022a;Alani et al, 2022;de Azevedo et al, 2022;Martínez-García et al, 2022;Qaidi et al, 2022;Zeybek et al, 2022). In addition to being environmentally friendly, steel fibers extracted from waste are more economical when compared to industrial steel fiber (Ghorpade and Rao, 2010;Mastali et al, 2018;Liew and Akbar, 2020).…”

Volume Deformation and Hydration Behavior of Ordinary Portland Cement/Calcium Sulfoaluminate Cement Blends

“…Reducing energy consumption and greenhouse gas emissions in the process of clinker production has become an urgent problem that the ordinary Portland cement (OPC) industry needs to address. Some cement-less or low-alkali cements have been produced to reduce the clinker content [ 1 , 2 , 3 ]. Calcium sulfoaluminate (CSA) cement is considered a low-energy cement that requires a low calcination temperature (1200 °C) and limestone content during manufacturing, resulting in low carbon, sulfur dioxide and oxynitride footprints [ 4 , 5 ].…”

Influence of Pretreatment Methods on Compressive Performance Improvement and Failure Mechanism Analysis of Recycled Aggregate Concrete

“…According to the relevant literature, about 40% of the construction garbage generated by the demolition of old buildings is concrete [ 2 ]. The recycling of concrete garbage not only satisfies the requirement of sustainable development, but also makes a huge contribution to the protection of the environment and the conservation of land resources [ 3 ]. At present, various types of recycled aggregates can replace natural aggregates to varying degrees for use in concrete materials, such as waste powder, fine and coarse marble aggregates [ 4 , 5 ], waste glass [ 6 , 7 , 8 ], recycled coal bottom ash [ 9 ], plastic waste [ 10 ], etc.…”