scholarly journals Slag Substitution as a Cementing Material in Concrete: Mechanical, Physical and Environmental Properties

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2845 ◽  
Author(s):  
María Eugenia Parron-Rubio ◽  
Francisca Perez-Garcia ◽  
Antonio Gonzalez-Herrera ◽  
Miguel José Oliveira ◽  
Maria Dolores Rubio-Cintas

A circular economy is a current tenet that must be implemented in the field of construction. That would imply the study of the possibilities of the use of waste generated, for obtaining materials the used in construction as replacements for the raw material used. One of these possibilities is the substitution of the cement by slag, which contributes to the reduction of cement consumption, decreasing CO2 emissions, while solving a waste management problem. In the present paper, different types of concrete made by cement substitution with different type of slags have been studied in order to evaluate the properties of these materials. Cement is replaced by slag from different steel mills, both blast furnace and ladle furnace slag. The percentages of slag substitution by cement are 30%, 40% and 50% by weight. Mechanical, physical and environmental properties have been evaluated. Compressive and flexural strength have been analysed as the main mechanical properties. As far as physical properties go, density and porosity tests were be reported and analysed, and from an environmental point of view, a leachate study was performed. It has been found that some kinds of slag (blast furnace slag) are very suitable as substitutes for cement, providing properties above those of the reference concrete, while other types (ladle furnace slag) could be valid for non-structural applications, contributing in both cases to a circular economy.

Author(s):  
V. Lepa ◽  
◽  
O. Prohnymak ◽  

The problem of the accumulation of waste from the metallurgical industry in Ukraine, in particular, blast furnace slag, has an economic and environmental component. Therefore, the main problems, first of all, include the absence of a criterion for the greening of the industrial sector among the priorities of Ukraine's economic policy. The article examines the situation in the slag industry of Ukraine, summarizes the existing experience of using metallurgical slags as technogenic raw materials. The problems of introducing a circular economy in the territory of intensive development of the metallurgical industry are considered primarily in the context of creating a flexible infrastructure for processing metallurgical waste, because the problem of waste is at the center of attention of the entire circular economy. But such an infrastructure cannot be created without overcoming the technological, economic, and institutional problems of utilizing blast-furnace slags in Ukraine, which hinder the creation of a slag processing industry on the principles of a circular economy. Based on the assessment of macroeconomic and environmental effects from the introduction of elements of a circular economy in the domestic metallurgical industry, the resource value of blast furnace slags as a technogenic raw material for the construction industry, in particular the cement industry, as well as road construction and other areas of use, has been proved. The ways of solving the economic and institutional problems of slag processing at the macro-, meso- and microeconomic levels are given, proposals are made to improve the legal framework for the development of the circular economy, the participation of the state, local authorities and business in the creation of a domestic industry for the processing of blast-furnace slag.


2017 ◽  
Vol 68 (6) ◽  
pp. 1182-1187
Author(s):  
Ilenuta Severin ◽  
Maria Vlad

This article presents the influence of the properties of the materials in the geopolymeric mixture, ground granulated blast furnace slag (GGBFS) + wheat straw ash (WSA) + uncalcined red mud (RMu), and ground granulated blast furnace slag + wheat straw ash + calcined red mud (RMc), over the microstructure and mechanical properties of the synthesised geopolymers. The activation solutions used were a NaOH solution with 8M concentration, and a solution realised from 50%wt NaOH and 50%wt Na2SiO3. The samples were analysed: from the microstructural point of view through SEM microscopy; the chemical composition was determined through EDX analysis; and the compressive strength tests was done for samples tested at 7 and 28 days, respectively. The SEM micrographies of the geopolymers have highlighted a complex structure and an variable compressive strength. Compressive strength varied from 24 MPa in the case of the same recipe obtained from 70% of GGBFS + 25% WSA +5% RMu, alkaline activated with NaOH 8M (7 days testing) to 85 MPa in the case of the recipe but replacing RMu with RMc with calcined red mud, alkaline activated with the 50%wt NaOH and 50%wt Na2SiO3 solution (28 days testing). This variation in the sense of the rise in compressive strength can be attributed to the difference in reactivity of the materials used in the recipes, the curing period, the geopolymers structure, and the presence of a lower or higher rate of pores, as well as the alkalinity and the nature of the activation solutions used.


2018 ◽  
Vol 174 ◽  
pp. 01006 ◽  
Author(s):  
Břetislav Teplý ◽  
Tomáš Vymazal ◽  
Pavla Rovnaníková

Efficient sustainability management requires the use of tools which allow material, technological and construction variants to be quantified, measured or compared. These tools can be used as a powerful marketing aid and as support for the transition to “circular economy”. Life Cycle Assessment (LCA) procedures are also used, aside from other approaches. LCA is a method that evaluates the life cycle of a structure from the point of view of its impact on the environment. Consideration is given also to energy and raw material costs, as well as to environmental impact throughout the life cycle - e.g. due to emissions. The paper focuses on the quantification of sustainability connected with the use of various types of concrete with regard to their resistance to degradation. Sustainability coefficients are determined using information regarding service life and "eco-costs". The aim is to propose a suitable methodology which can simplify decision-making in the design and choice of concrete mixes from a wider perspective, i.e. not only with regard to load-bearing capacity or durability.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2131 ◽  
Author(s):  
G.U. Ryu ◽  
G.M. Kim ◽  
Hammad R. Khalid ◽  
H.K. Lee

Blast furnace slag, an industrial by-product, is emerging as a potential raw material to synthesize hydroxyapatite and zeolite. In this study, the effects of temperature on the hydrothermal synthesis of hydroxyapatite-zeolite from blast furnace slag were investigated. Specimens were synthesized at different temperatures (room temperature, 50, 90, 120, or 150 °C). The synthesized specimens were analyzed qualitatively and quantitatively via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), BET/BJH, and scanning electron microscopy/energy dispersive using X-ray analysis (SEM/EDX). It was found that the hydroxyapatite phase was synthesized at all the reaction temperatures, while faujasite type zeolite appeared in the specimens synthesized at 90 and 120 °C. Moreover, faujasite was replaced by hydroxysodalite in the specimens synthesized at 150 °C. Additionally, the crystals of the hydroxyapatite tended to become larger and total crystallinity increased as the reaction temperature increased.


Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1313
Author(s):  
Angélica Lozano-Lunar ◽  
Auxi Barbudo ◽  
José María Fernández ◽  
José Ramón Jiménez

Among the actions proposed by the European Union for the implementation of Circular Economy is the use of waste as a secondary raw material (SRM). During the fusion of the scrap, a steel dust is generated, named Electric Arc Furnace Dust (EAFD). The EAFD is composed mainly of potentially leachable heavy metals, so is classified as “hazardous” waste. Around the world, approximately 70% of this waste is deposited in landfills, with a previous treatment through cement-based materials to prevent the metals’ mobility. However, this action is not in accordance with the Circular Economy concept due to the greater use of resources and the loss of deposited metals. The present investigation analyses the use of EAFD as SRM in conventional mortar production for its use as a construction material. Different substitution percentages (25%, 50% and 100%) were used replacing siliceous filler by EAFD. The investigation analysed the behaviour of conventional mortars by tests of workability, compressive strength, water absorption by capillarity and leaching behaviour in granular and monolithic state. The results obtained indicate a slight improvement in mechanical behaviour with the incorporation of EAFD, the reason why its use as SRM in conventional mortars would benefit the construction industry and would encourage the Circular Economy. From an environmental point of view, the mechanisms of Pb fixation should be improved in granular state.


2014 ◽  
Vol 937 ◽  
pp. 462-464 ◽  
Author(s):  
Wei You ◽  
Yan Mei Jiang ◽  
Qian Lin ◽  
Xiao Xia Yu ◽  
Peng Fei Li ◽  
...  

The blast furnace slag is an industrial solid waste in the production process, this paper deals with the blast furnace slag as products -- artificial jade cup handicraft lost wax casting process of high additional value of main raw material, firstly analyses the production process of chemical composition and artificial jade common blast furnace slag and natural jade, then the detailed design of the lost wax casting process of artificial jade cup, including manufacturing, shell mould manufacturing, dewaxing, baking, imitation jade material melting and casting. The lost wax casting method for producing artificial jade crafts complex products, the added value of products, so as to achieve a high added value utilization of blast furnace slag.


2018 ◽  
Vol 272 ◽  
pp. 273-279 ◽  
Author(s):  
Břetislav Teplý ◽  
Tomáš Vymazal ◽  
Pavla Rovnaníková

Efficient sustainability management requires the use of tools that enable the quantification, measurement or comparison of material, technological and construction variants. Tools of this kind which have been developed around the world in recent years include various indicators, indexes, etc. Generally, technical, economic, ecological and socio-cultural areas must all be included. Such a tool can be used as a powerful marketing aid and as support for the transition to the “circular economy”. Life Cycle Assessment (LCA) procedures are also used, alongside other approaches. LCA is a method that evaluates the life cycle of a structure from the point of view of its effect on the environment. Processes starting with the mining of mineral resources and including their transport, production and use up to their final processing as waste (recycling) are all taken into account. In addition, consideration is given to energy and raw material costs, and to environmental impact throughout the whole life cycle – e.g. through emissions. The presented contribution focuses on the quantification of sustainability connected with the use of various types of concrete with regard to their resistance against the effect of degrading influences. Sustainability factors are also determined using information regarding service life and “eco-costs”. The aim is to present a suitable methodology which can simplify decision-making concerning the design and choice of concrete mixes from a wider perspective, i.e. not only from the aspects of load-bearing capacity or durability.


2014 ◽  
Vol 692 ◽  
pp. 454-459
Author(s):  
Shu Gang Hu ◽  
Xian Jun Lu ◽  
Hai Li Niu

According to XRD, DTA and SEM detections, the hydration products of blast furnace slag based cementing material SL, SLG. were studied in different age periods. The XRD analysis of cementing material SL hydration products showed the composition of hydration products were mainly amorphous substances, few crystalline substances. Characteristic peak of ettringite, such as AFt, hadn’t been found in the spectral line of DTA, and it hadn’t been found in the figures of SEM, either, which was accordant with the conclusion that the cementing performance of SL mainly coming from gel of hydrated calcium silicate (CSH) and hydrated calcium aluminate. But the cementing performance of SLG mainly coming from Aft, CSH and AFm from hydration products analysis of different age periods.


2019 ◽  
Vol 38 (2019) ◽  
pp. 726-732 ◽  
Author(s):  
Yi-ci Wang ◽  
Wen-bin Xin ◽  
Xiao-geng Huo ◽  
Guo-ping Luo ◽  
Fang Zhang

AbstractIn this study, the blast furnace slag of the Baotou Steel and Iron Company was used as the main raw material to prepare glass ceramics with diopside as the main crystal phase. The composition of the parent glass was designed by thermodynamic calculations with FactSage software. Small amounts of the nucleation agent Cr2O3 were then added to the parent glass to induce crystallization. Differential thermal analysis was used to determine the nucleation and crystallization temperatures of the glasses, and scanning electron microscopy and X-ray diffraction were adopted to determine the microstructures and phase compositions of the glasses after heat treatment, respectively. The results showed that glass ceramics of the diopside phase can be prepared with up to 73 wt% blast furnace slag when 1.44–1.91 wt% Cr2O3 is added, and the ceramics have uniform compact grains and a high bending strength of about 84.6–101.7 MPa. In addition, the mechanical properties are better than those of natural marble and granite. These results provide basic information and a scientific basis for industrial production of diopside glass ceramics using molten blast furnace slag as the main raw material.


2019 ◽  
Vol 138 (6) ◽  
pp. 4571-4583
Author(s):  
Anna A. Kuśnierz ◽  
Magdalena Szumera ◽  
Magda Kosmal ◽  
Paweł Pichniarczyk

Abstract A glass set with a high content of blast-furnace slag and a reduced amount of traditional raw materials requires optimization of the raw material composition and adjustment of its specificity to the temperature regime of melting, homogenizing and clarifying the glass mass. The introduction of an increased amount of blast-furnace slag allows to reduce the cost of raw materials: soda, limestone and high-class sand, reduce energy costs, whose consumption significantly decreases and reduces CO2 emissions in line with EU requirements. The tests of thermal analysis of a glass set with different contents of Calumite are aimed at learning the mechanism of its operation by determining the changes caused by its different presence in the course of subsequent reactions between the components of the glass set. Analysis of the influence of the addition of different Calumite slag contents treated as a substitute for the raw material on the melting process of glassware sets was analyzed. The tests were carried out using differential thermal analysis (DTA) and thermogravimetry (TG) based on the model glass [mass%]: 73.0% SiO2, 1.0% Al2O3, 10.0% CaO, 2.0% MgO and 14.0% Na2O. The effect of combining Calumite with sulphate and multi-component fining agent—mixtures of As2O3, Sb2O3, NaNO3 in proportions of 1:1:1 for chemical reaction and phase transformation, was investigated.


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