Development of Alkali-Activated Porous Concrete Composition from Slag Waste

Abstract

In this paper, a porous alkali-activated slag concrete was developed that can be used in the construction sector as a sustainable building material and potentially as an alternative to the aerated concrete products currently on the market. Ferrous slag from the metallurgical industry (Finland) and phosphogypsum from a fertilizer plant (Lithuania) were used as precursors in alkali-activated systems. The addition of hydrogen peroxide and phosphogypsum led to positive changes in the final properties of the test material. Porous concrete based on alkali-activated slag was analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) methods. The compressive strength, density, thermal conductivity and porosity of the hardened specimens were evaluated as well. Research is being conducted with the material in question to create a cheap, particularly low-energy demanding building material. This material must have suitable mechanical properties for the structure and, at the same time, suitable thermal conductivity properties. It was determined that this porous concrete had compressive strength in the range of 2.12–7.95 MPa, density from 830 kg/m3 to 1142 kg/m3, and thermal conductivity in the range of 0.0985–0.2618 W/(m·K). The results indicate that the recommended content of phosphogypsum in alkali-activated material is 3–5% due to the optimal distribution of the mechanical and thermal properties and the conductivity. Alkali-activated slag and phosphogypsum material can be used in the manufacture of low-strength insulation blocks and to protect structures from the effects of high temperatures.

Application of the Industrial Byproduct Gypsum in Building Materials: A Review

“…The production of PG-based lightweight concrete consumes 74 billion tons of waste per year, and if planted on these lands, it can indirectly release more than 90,000 tons of oxygen, which greatly improves the environment. To recycle PG for the production of porous concrete, ferrous slag, cement, hydrogen peroxide were added to prepare concrete [74]. The results of the study showed that hydrogen peroxide and PG had a positive effect on the performance of the system, while the strength of the concrete was up to 7.95 MPa and the density was as low as 830 kg/m 3 , and the final optimum admixture of PG was 5%.…”

Research on Mechanical and Shrinkage Characteristics of a Resource-Based Cement Solid-Waste Concrete

“…Furthermore, it explores the development trend of the strength and shrinkage characteristics of the aforementioned materials under the influence of waste slag ratio, cement dosage and time, and clarified the microstructure of the concrete by Scanning Electron Microscope (SEM). Then, it comprehensively investigated the formation mechanisms of strength and shrinkage performance, aiming at providing a reference for relieving the pressure of natural sand and gravel mining, consuming industrial solid waste, building a sustainable green economic system in China and promoting the early formation of social double carbon strategy [ 32 , 33 ].…”