Design and Preparation Technology of Green Multiple Solid Waste Cementitious Materials

Area of Science:

• Materials Science
• Civil Engineering
• Environmental Science

Background:

• Current research on cementitious materials often overlooks comprehensive solid waste design for mechanical properties and durability.
• A gap exists in understanding the synergistic effects of multiple solid wastes in cementitious applications.

Purpose of the Study:

• To explore the mix design and properties of multi solid waste cementitious materials (MSWCMs) using steel slag (SS), slag powder (SP), desulfurization gypsum (DG), fly ash (FA), and ordinary Portland cement (OPC).
• To investigate the impact of these solid wastes on both microscopic and macroscopic properties.

Main Methods:

• Orthogonal experimental design was employed to determine optimal mix proportions.
• Characterization included compressive strength testing, drying shrinkage measurement, chloride ion resistance tests, X-ray Diffraction (XRD), Thermogravimetric-Differential Thermogravimetric (TG-DTG) analysis, and Nuclear Magnetic Resonance (NMR) spectroscopy.

Main Results:

• The optimal MSWCM mix (50% OPC, 10% SS, 20% SP, 5% DG, 15% FA) achieved a 28-day compressive strength of 50.7 MPa, outperforming control and blank groups by 14% and 7.6%.
• Significant improvements were observed in drying shrinkage (up to 22.9% reduction) and chloride ion resistance (up to 22.6% increase).
• Microscopic analysis revealed synergistic effects leading to increased ettringite (AFt) and C-(A)-S-H gel formation.

Conclusions:

• The synergistic interaction of multiple solid wastes significantly enhances the mechanical properties and durability of cementitious materials.
• This optimized MSWCM formulation offers a sustainable alternative to traditional cement, yielding substantial economic and environmental advantages by reducing cement consumption.