Granulated Blast Furnace Slag Powder Research Articles

Optimizing Concrete Strength and Sustainability by Using Blast Furnace Slag and Waste Glass Powder as Additives

ABSTRACTConstruction industry intends to promote effective utilization of waste materials obtained from various sources to develop an eco‐friendly building material for high performance, life cycle sustainability, and reduction of carbon footprints globally. The current study focusses to produce concrete mix by using industrial wastes such as ground granulated blast furnace slag (BOF) and glass powder (GP). Samples are prepared by utilizing industrial wastes partially for M35 grade concrete. The ground granulated BOF and GP are used with 10%–40% and 0.1%–0.4%, respectively, as the partial replacement of cement. Under different curing periods, the specimens were characterized for their physical and mechanical properties. Test results were analyzed to check the workability, compressive strength, flexural strength, and water absorption of the sample mixes prepared. The highest compressive and flexural strength of the samples are found to be 46.23 MPa and 5.13 MPa, at the optimal replacement of BOF and GP in the proportion of 30% and 0.2%, respectively.

Synergistic effects of GGBFS and EAFS on rheology, mechanical properties, and durability of self-compacting concrete: Experiments, predictions, and life cycle assessment

With the aim of reducing the use of natural resources, this research evaluated the behavior of self-compacting concrete (SCC) containing granulated blast furnace slag (GGBFS) powder instead of limestone powder, GGBFS fine aggregate instead of natural fine aggregate, and electric arc furnace slag coarse aggregate (EAFS) instead of natural coarse aggregate. The evaluation included a comprehensive assessment of fresh concrete properties, compressive strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, and capillary water absorption. In addition, equations were proposed to predict the compressive strength of concrete in terms of the type and percentage of material replacement and curing time. Finally, the environmental effects of the concrete mixtures were studied, which fills a significant research gap. The results showed that with the optimal use of the mentioned substitute materials in concrete, the properties of fresh concrete, hardened concrete, and durability are improved. Using 45% GGBFS powder, 30% GGBFS fine aggregate, and 45% EAFS coarse aggregate, the concrete properties improved in comparison to the reference concrete. However, the results of the life cycle assessment showed that this mix design has more harmful effects on the environment than other designs of the present research. It should be noted that if these materials were not used in concrete, the same amount of damage would have been occurred due to their disposal.

The effect of slag and natural pozzolan on the rheological and compressive strength properties of recycled self-compacting mortar

Cement replacement materials are used in self-compacting concrete mixes to reduce the cement content and hence its environmental effect. This article examined the effects of ground granulated blast-furnace slag (S) and natural pozzolan (NP) powder on the rheological and mechanical properties of recycled self-compacting mortar (RSCM). Natural sand was replaced by 100% of recycled sand (RS) by volume; while cement was replaced by slag and NP up to 40% by weight of cement. The slump flow, V-funnel time, yield stress and plastic viscosity and compressive strength of RSCM are investigated and compared with natural self-compacting mortar. The results showed that fresh properties of RSCM meet the requirements of self-compacting mortar if slag and NP contents are limited to 35%. The increase in slag content increases the yield stress and the plastic viscosity of fresh mortars whereas a decrease in the rheological properties is noticed when NP content is increased. Increasing slag and NP content leads to a reduction in compressive strength of RSCM at early ages, but enhances compressive strength at later age. The cement substitution levels by 25% of slag and 15% of NP are the optimum for attaining the desired strength that compensate for strength loss due to the use of RS.

Self-consolidating paste systems using ground granulated blast furnace slag and limestone powder mineral admixtures

This study aims to investigate the blends of supplementary cementitious ground granulated blast furnace slag (GGBFS) with limestone powder (LSP) as mineral admixtures to partially replace cement (up to 30 %) in self-consolidating paste (SCP) systems made at respective water demands. Besides the control formulation (100 % cement), the first set of SCP systems includes GGBFS alone as a partial substitute of cement (5 %, 10 %, 15 %, and 20 %), whereas the second set contains blends of 10 % GGBFS with 10 % and 20 % LSP. For all the seven formulations (1 control, 4 binary and 2 ternary), tests were performed to determine their water demand, setting times and flow behavior, hydration kinetics, mechanical strengths and microstructural properties. Results showed that the fresh and hardened state properties of SCP systems incorporating GGBFS and LSP led to an increase in strength, hydration kinetics were slightly improved and hence enhancement of strength and microstructure of SCP systems. Reduction in initial and final setting times recorded with increased LSP from 10 % to 20 % in ternary SCP formulations. Early compressive strength due to LSP increased in ternary SCP systems as compared to binary formulations, which reflected synergy between GGBFS and LSP in SCP systems. Moreover, environmental assessment results indicate a significant reduction in CO2 emissions by substituting cement with GGBFS and LSP. These findings indicate that both GGBFS and LSP can be successfully used in developing high performance and environment friendly self-compacting concrete (SCC).

Low carbon research in precast concrete based on the synergistic mechanism of red mud-ground granulated blast furnace slag powder

The synergistic effect red mud (RM) and ground granulated blast furnace slag (GGBS) in cementitious materials has been widely reported, which is attributed to improve the performance of low-clinker cement. However, the existence of synergistic effect between RM and GGBS under high-temperature steam curing conditions has rarely been studied. In order to maximize the use of solid waste for the purpose of low carbon and conserving resources, 65% RM and GGBS were used to replace cement for the preparation of precast concrete, and two types of water/binder (W/B) ratios and steam curing temperatures were set to investigate the synergistic effect of multisolid waste under high-temperature steam curing conditions. With decreasing RM and increasing GGBS, the demolding strength of precast concrete samples cured by 60 °C with two different W/B ratios decreases, but the demolding strength rises and then decreases when the steam curing temperature is 80 °C. This suggests that the simultaneous use of two mineral admixtures in place of cement at 80 °C produces a significant synergistic effect and is able to increase the demolding strength of the samples by up to 50%. The change in compressive strength of precast concrete samples from 3 to 90 d is significantly different from the demolding strength. At a W/B ratio of 0.3, there is still prominent synergy between RM and GGBS after 28 d of hydration of precast concrete samples at both steam curing temperatures. In contrast, with a high W/B ratio (0.45), the synergistic effect is not evident throughout the period at either steam curing temperature. From the results of the whole experiment, synergistic effect between GGBS and RM is more pronounced at low W/B ratios or high steam curing temperatures. This study provides a new idea for the synergistic utilization of high-dose of multisolid waste in the preparation of precast concrete under high-temperature curing conditions.

Life cycle assessment of waste materials in deep cement mixing for land reclamation in Hong Kong

In recent years, researchers have shown increasing concern on the environmental impact attributed to traditional binders like cement, especially in mega-scale reclamation projects utilizing Deep Cement Mixing (DCM). The substitution of cement with alternative binders derived from construction and demolition waste as well as industrial slag waste is viewed as a potential strategy for mitigating the carbon footprint of this construction sector. In this study, the potential of using ground granulated blast furnace slag (GGBS), steel slag (SS), and waste concrete powder (WCP) to partially replace cement in construction projects involving DCM is assessed based on a case study in Hong Kong. A detailed comparison through Life Cycle Assessment (LCA) is conducted to examine the carbon footprint of alternative binders. Various scenarios that involve substituting cement to different extents with alternative binders generated from waste materials have been considered. The results reveal that the grinding process is the main contributor to the Global Warming Potential (GWP) for GGBS and SS, accounting for over 57% in each case. For WCP, the GWP is distributed across separation, sieving, and loading. Utilizing alternative waste leads to a GWP reduction in all scenarios, primarily due to lower emissions from these secondary raw materials. Overall, substituting 60% of Portland cement with GGBS, SS, or WCP in DCM construction resulted in GWP reductions of 34.7%, 34.5%, and 35.8% of greenhouse gas emissions, respectively. Various transportation scenarios are explored when moving the supply of construction materials from a local to a regional level by considering various material suppliers and the associated transportation distance. The sensitivity analysis highlighted the significant impact of transportation distance on GWP. This underscores the importance of logistics analysis in land reclamation projects and the benefits of integrating alternative binders into DCM projects.

Cleaner, sustainable, and safer: Green potential of alkali-activated materials in current building industry, radiological good practice, and a few tips

Alkali-activated materials were prepared from four typical precursors (coal fly ash, granulated blast furnace slag, metakaolin, and brick waste powder) characterized for granulometry, elemental composition, and microstructure. High-resolution gamma-ray spectrometry was used to determine the activity concentration of Naturally Occurring Radioactive Materials (NORM) in all the materials to assess their radiological impact. All the investigated materials have been found to comply with the European dosimetric index (I) according to Directive 2013/59/Euratom. The results suggest the need for an accurate check of radioactivity throughout the mixing phases to prevent I exceedances. The productive chains were also evaluated by principal component analysis.

Strength and elevated temperature resistance properties of the geopolymer paste produced with ground granulated blast furnace slag and pumice powder

The production of cement results in large amounts of CO2 emissions. In order to reduce the energy consumption and gas emissions associated with cement production, a new technology called geopolymerisation has been developed to produce concrete without the use of cement by using aluminosilicate materials as raw materials. The purpose of this study is to evaluate the effect of various parameters on the geopolymer based slag/pumice paste. Slag (GGBFS) and pumice powder were used as binders in different slag/pumice ratios (100:0, 90:10, 80:20, 70:30 and 60:40) and activated with sodium hydroxide (NaOH) at 12 and 14 M concentration and cured for 3 and 7 days at 65 °C temperature. The effect of these parameters on compressive strength and resistance to elevated temperatures was investigated. Microstructural (SEM, EDX) and chemical (FT-IR, XRD) analyses were also carried out to determine the effect of slag/pumice ratio, NaOH concentration and curing time on the properties of the geopolymer pastes. The results showed that the use of slag significantly increased the compressive strength, while the use of pumice with slag increased the resistance of geopolymer pastes to elevated temperatures. For the geopolymer paste produced with slag, high compressive strength can be obtained by a long period of oven curing, whereas for pumice a short period of oven curing and a long period at low temperature can be used. In conclusion, the most effective of the different parameters was the percentage of slag/pumice in the first degree and then the molarities of NaOH, while the least effective parameter was the curing time.

Fly-ash and GGBS based geo-polymer concrete with granite powder as partial replacement of M-Sand for sustainability

In the present scenario, the usage of sustainable developing materials in the construction industry is popular nowadays. The primary role in the production of ecologically friendly concrete is the creation of geopolymer concrete. Industrial by-products used as base material or replacements for cement are trending. In that manner, the utilization of industrial by-products was used as an admixture or replacement material in this geopolymer concrete production. This research attempted to make a green concrete of Geopolymer Concrete (GPC) using fly ash, Ground Granulated Blast Furnace Slag (GGBS), Manufactured Sand (M-Sand) and Granite powder (GP) used with alkaline solutions mixture of sodium hydroxide and sodium silicate with water was used. At 10, 12, 14, and 16 M molarity, the effect of granite waste powder on geopolymer fresh and mechanical qualities are studied. Embodied energy parameter performances of GPC are also shown in this study. When compared to regular concrete, the GPC series produces less carbon dioxide. In this work, 90% of fly ash and 10% of GGBS were used as a cementitious material, M- sand was used as a fine aggregate, and different proportions of 10, 15, and 20% of replacement were done by granite powder. The mechanical properties of compressive strength, Split tensile strength, and stress–strain behavior of geopolymer concrete were investigated. The test of the concrete was carried out at the age of 7 days, 14 days, and 28 days. The inference of the work is concluded that Fly ash, GGBS with GP as partial replacement to M Sand shall be used for construction application where the early gain of strength is recommended. Nevertheless, more studies have to be carried out for further conclusions in applications related to mixing at site, transportation and placement and compaction aspects of GPC mixes in the construction industries.

Comparative study on the effect of different supplementary cementitious materials on Alkali-silica reaction of self-compacting concrete

Self-compacting concrete (SCC) has been increasingly used in construction industry especially in prefabricated concrete applications. Alkali-silica reaction (ASR) is a deleterious reaction between reactive aggregate and alkalis in cement. This reaction can lead to serious expansion and cracking in concrete, causing major structural problems. The deployment of supplementary cementitious materials (SCMs) emerges as a promising solution to counter ASR effects. Therefore, it is important to understand the role SCMs can play to eliminate the effect of ASR in SCC. In this study, the effect of ground granulated blast-furnace slag (GGBS), fly ash (FA) and limestone powder (LSP) on the potential of ASR in SCC was assessed. To evaluate ASR, two standardized methodologies, RILEM AAR-4 and ASTM C1260, were adopted. Additionally, assessments encompassed fresh and hardened properties, alongside transport dynamics such as permeability and capillary absorption. It was found that the properties of fresh and hardened concrete are greatly affected by the type of SCMs used. The main findings of the study showed that SCC-GGBS outperformed other SCMs against ASR.

New insights into the production of sustainable synthetic aggregates and their microstructural evaluation

In this study, a novel technique for producing synthetic aggregates using industrial by-products was experimentally investigated. Taguchi method is used to identify the optimum mix design proportion to develop durable synthetic aggregates. For this, different combinations of quaternary binders including ordinary Portland cement, ground granulated blast furnace slag, metakaolin, and lime powder was used. The obtained results revealed that the synthetic aggregates prepared with optimized mortar mix enhanced the compressive strength by 5.9%. Then the performance of synthetic aggregates was evaluated based on their mechanical and durability properties. Microstructural properties of the produced aggregates were examined. The results showed that optimum mix is highly effective than control mix. The manufactured synthetic aggregates are in accordance with the ASTM C 330 standard requirements. Therefore, our study contributes to the advancement in the sustainability by developing a method for producing synthetic aggregates from industrial byproducts.

Development of sustainable ultra-high-performance concrete containing ground granulated blast furnace slag and glass powder: Mix design investigation

Ultra-high performance concrete (UHPC) is one of the most important advances in concrete technology. Since UHPCs possess outstanding mechanical properties and durability, they require less material consumption and post-maintenance conventional concrete. This helps reduce the detrimental impacts of concrete structures on the natural environment. However, the high price and high carbon intensity of UHPCs are main hurdles for their wide adoption. Recently, studies have revealed that waste glass at a certain fineness exhibits pozzolanic behaviour. This paper investigates the effect of replacing cementitious components in UHPCs with “medium-size” glass powder (GP) on the workability, mechanical properties, sustainability, and cost efficiency of the UHPCs. While principal binders (cement and silica fume (SF)) were replaced by “medium-size” GP in Series I, ground granulated blast furnace slag (GGBFS) and coarse GP were simultaneously used to substitute for SF in Series II. Regardless of curing regimes, slag GP-UHPC mixtures always exhibited better workability and greater compressive/flexural resistance, indicating the great synthetic effect of GP and GGBFS substitution. In addition, results showed that up to 30% of GP replacement, most specimens yielded reasonable mechanical properties, high cost efficiency, and low carbon indexes compared to the reference mixture. Specifically, while workability reduced with the increase of GP portions in the GP-UHPCs, it rose with larger replacement percentages of SF in the slag GP-UHPCs. For both series, 20% replacement of GP was the optimal ratio, resulting in cost-saving and carbon-efficient mix designs with comparable compressive/flexural capacity.

Effects of Steel Slag Powder Content and Curing Condition on the Performance of Alkali-Activated Materials Based UHPC Matrix.

The accumulation of steel slag and other industrial solid wastes has caused serious environmental pollution and resource waste, and the resource utilization of steel slag is imminent. In this paper, alkali-activated ultra-high-performance concrete (AAM-UHPC) was prepared by replacing ground granulated blast furnace slag (GGBFS) powder with different proportions of steel slag powder, and its workability, mechanical properties, curing condition, microstructure, and pore structure were investigated. The results illustrate that the incorporation of steel slag powder can significantly delay the setting time and improve the flowability of AAM-UHPC, making it possible for engineering applications. The mechanical properties of AAM-UHPC showed a tendency to increase and then decrease with the increase in steel slag dosing and reached their best performance at a 30% dosage of steel slag. The maximum compressive strength and flexural strength are 157.1 MPa and 16.32 Mpa, respectively. High-temperature steam or hot water curing at an early age was beneficial to the strength development of AAM-UHPC, but continuous high-temperature, hot, and humid curing would lead to strength inversion. When the dosage of steel slag is 30%, the average pore diameter of the matrix is only 8.43 nm, and the appropriate steel slag dosage can reduce the heat of hydration and refine the pore size distribution, making the matrix denser.

Development of low-carbon materials from GGBS and clay brick powder for 3D concrete printing

A new low-carbon material for 3D concrete printing by utilizing recycled ground granulated blast-furnace slag (GGBS) and clay brick powder (CBP) was developed to reduce the carbon footprint. The printability and hardened properties of 3D printed mortar were systematically investigated to reveal the coupling effect of GGBS and CBP. The results indicate that the printability of mortar is significantly influenced by the morphology and particle size distribution of admixtures. The vitreous surface of GGBS reduces the yield stress of the paste, while the porous surface of CBP has the opposite effect. Furthermore, increasing CBP replacement leads to a denser packing of binders, which releases more free water to increase the fluidity of mortar. The printing process not only increases the proportion of capillary and macro pores, but also reduces the sphericity of macro pores. As a result, 3D printed mortar experiences a 10 ∼ 50 % loss in compressive strength and mechanical anisotropy of 3D printed mortar. The secondary hydration reaction of GGBS and CBP reduces the average pore diameter from 41.7 nm to 15.3∼19.3 nm and increases the complexity of micro pores, resulting in a significant decrease in chloride ions migration in the mortar. These results demonstrate the feasibility of using low-carbon materials containing GGBS and CBP for 3D concrete printing.

Synthesis, Stability and Microstructure of a One-Step Mixed Geopolymer Backfill Paste Derived from Diverse Waste Slags

The advent of industrialization has produced an enormous amount of industrial waste slag, which drastically pollutes environmental resources. This study examines the production, stability, and microstructure of a novel backfill geopolymer paste derived from multiple industrial waste slags, including silica-alumina precursors (low-calcium composition) and waste slags (high-calcium composition), as well as two additives. The characteristics of self-hardening were discovered. The effects of low-calcium fly ash, granulated blast furnace slag, red mud, and lime powder on fluidity and compressive strength were then evaluated. To assess the stability, the resistances to drying shrinkage, permeability, and chemical attack by an optimized geopolymer backfill paste were investigated. Furthermore, SEM-EDS, XRD, FTIR, and TG-DSC tests were employed to reveal the microstructures, products, and thermal stability. The results show that the backfill paste hardens well and has no impact on alkalinity dissolution for adjacent soils and water. The optimum sample, P1, had a water-binder ratio of 0.70, resulting in 201 mm fluidity and 2.1 MPa 28-d compressive strength. In terms of drying shrinkage, permeability, and Na2SO4 and NaCl solution attack, sample P1 outperformed the conventional Ordinary Portland cement paste (OPC) for 90 days. The paste P1 containing about 46.0 wt% waste slags meets the fresh and hardened property requirements for goaf backfill, and the chemical binding of P1 is acquired from the mixture of (N,C)-A-S-H, C-S-H, and C-A-S-H gel products. These findings lay the groundwork for the scientific application of a wide range of waste slags in backfill engineering.

Utilization of ground granulated blast-furnace slag powder in brick industry: A new generation building material

This study presents research on the use of geopolymer bricks in construction, which are made using materials such as fly ash, GGBS, sand, cement, and alkali activators. The study focuses on the use of GGBS as a fractional replacement for cement in the bricks and investigates the effects of different molarities and silicate-to-hydroxide (S/H) ratios on the properties of the bricks. The results show that the bricks made with a molarity of 10 M and S/H ratio of 2.5 had the highest compressive strength of 27.22 MPa. The study suggests that using geopolymer bricks is a more environmentally friendly and cost-effective option than traditional fly ash or burnt clay bricks in the construction industry.

Utilization of optimized microwave sintering to produce safe and sustainable one-part alkali-activated materials

Sodium hydroxide (NaOH) as an alkaline activator presents a vital limitation in the mass production of alkali-activated binders due to its severe effect on users’ safety. In this study, safe and sustainable one-part alkali-activated slag mixes (OP-AAS) were prepared through an efficient microwave sintering for a mixture of active amorphous ground granulated blast furnace slag (GGBFS) and sodium hydroxide powder (NaOH). Different microwave-sintered powders were prepared using microwave energy of power 900 W for the mixture at different treatment periods (10, 20, and 30 min). Fresh and hardened properties of different OP-AAS mixes were studied. Moreover, the phase composition and microstructure were investigated using X-ray diffraction (XRD) analysis and scanning electron microscope (SEM). Cytotoxicity/viability testing was performed to evaluate the cell death induced by the developed materials to measure their safety for the user. According to compressive strength, cytotoxicity/viability analysis, environmental impact and cost calculation of developed OP-AAS, it is concluded that employing microwave sintering for a short duration is sufficient to produce safe binding materials with adequate mechanical properties suitable for commercial applications in the construction sector.

Effect of Sodium Silicate on the Hydration of Alkali-Activated Copper-Nickel Slag Materials

This paper studied the influence of the modulus and dosage of sodium silicate on the hydration of alkali-activated copper-nickel slag (CNS) materials. CNS was used as the main raw material, and ground granulated blast furnace slag (GBFS) powder was selected as the mineral additive. The hydration and hardening mechanisms were discussed. The experimental results showed that [SiO4]4− and [AlO4]5− with a high degree of polymerization in the CNS glassy phase more easily underwent depolymerization-condensation and produced more C-S-H gels when the modulus was small and the sodium silicate dosage was high. When the content of sodium silicate was 7.0% and the modulus of sodium silicate solution was 1.0, the 28-day compressive strength of the material reached 125 MPa. This alkali-activated copper-nickel slag material can be used for mine filling, which has certain economic and ecological benefits.

Sustainable Design of Self-Consolidating Green Concrete with Partial Replacements for Cement through Neural-Network and Fuzzy Technique

In order to achieve a sustainable mix design, this paper evaluates self-consolidating green concrete (SCGC) properties by experimental tests and then examines the design parameters with an artificial intelligence technique. In this regard, cement was partially replaced in different contents with granulated blast furnace slag (GBFS) powder, volcanic powder, fly ash, and micro-silica. Moreover, fresh and hardened properties tests were performed on the specimens. Finally, an adaptive neuro-fuzzy inference system (ANFIS) was developed to identify the influencing parameters on the compressive strength of the specimens. For this purpose, seven ANFIS models evaluated the input parameters separately, and in terms of optimization, twenty-one models were assigned to different combinations of inputs. Experimental results were reported and discussed completely, where furnace slag represented the most effect on the hardened properties in binary mixes, and volcanic powder played an effective role in slump retention among other cement replacements. However, the combination of micro-silica and volcanic powder as a ternary mix design successfully achieved the most improvement compared to other mix designs. Furthermore, ANFIS results showed that binder content has the highest governing parameters in terms of the strength of SCGC. Finally, when compared with other additive powders, the combination of micro-silica with volcanic powder provided the most strength, which has also been verified and reported by the test results.

Procedure for mix designing used for steel fibre reinforced self-compacting concrete

This work focuses on a methodical design process for developing self-compacting concrete (SFRSCC) using steel fibre reinforcements. The objective is to create a self-consolidating concrete that has the double advantage of self-consolidating characteristics and composite toughness. Experimental modelling involved building the mortar phase with manufactured sand (M-sand) as fine aggregate utilising a systematic mix design process based on the particle packing idea. Optimisation of aggregates was determined using the packing density idea and slump cone research. By conducting a paste consistency test, cement and ground granulated blast furnace slag (GGBFS) powder combinations were chosen. Finally, the amount of superplasticizer was determined based on Marsh cone experiments and the percentage by volume of steel fibres determined by slump flow research. The addition of steel fibre dosage impacts the workability of both standard and high strength concrete, and the fresh properties emphasised the necessity to maintain a large paste volume for increased workability. On the basis of the recommended mix design technique using M-sand, self-compacting concrete with a maximum strength of 70MPa was manufactured. On the other hand, experimental studies on the fresh and hardened properties of recommended self-compacting steel fibre concrete mixes were presented. In addition, test findings demonstrated the viability of employing M-sand as a replacement for river sand in its entirety.