Combination Of Ground Granulated Blast Furnace Slag Research Articles

Mechanical properties and microstructure of engineered cementitious composites with high volume steel slag and GGBFS

Engineered cementitious composites (ECC) achieve exceptional ductility and durability, but the heavy reliance on cement has notable environmental impacts. In this work, the steel slag (SS) and ground granulated blast furnace slag (GGBFS) are introduced into ECC by largely substituting cement. The impact of SS and GGBFS content on ECC’s mechanical performance is analyzed at macro and micro scales in terms of fiber dispersion, mechanical properties, cracking patterns, cement hydration, and microstructure. The results demonstrate that SS can enhance fiber dispersion due to the low water demand and the strong electronic double layer formed on the surface of SS particles. While ECC with a high volume of SS alone (60 wt% SS) lacks the necessary strength for structural applications, the combination of GGBFS and SS exhibits favorable hydration properties and can effectively refine the pore structure. Thus, ECC with GGBFS and SS attains ideal toughness. ASTM C 1018 based toughness indices reveal that the Imax of ECC with 30 wt% GGBFS and 30 wt% SS is 2.30 times that of OPC based ECC. A sustainability analysis demonstrates that substituting 30 wt% SS and 30 wt% GGBFS for cement leads to a 33% reduction in energy consumption and a 53% decrease in CO2 emissions of ECC.

Effect of waste stream materials on properties of cement mortars when used as supplementary binding materials

The present study focuses on the effect of waste stream materials on various properties of cement mortar when the waste materials are used as supplementary binding/cementitious materials (SCMs) for partial replacement of binding material. The effect and properties of various types of SCMs that are commonly used in mortar preparation replacing a part of cement (%) like limestone dust (LS), cement kiln dust (CKD), ground granulated blast furnace slag (GGBS), dolomitic limestone (DLS), ladle furnace slag (LDF), silica fume (SF), ceramic wastes (CW), fly ash (FA), pulverized fuel ash (PFA), waste glass sludge (WGS), etc. are studied and presented. Effects and characteristics of various combinations of different supplementary binding materials like the combination of FA with LS, an amalgamation of FA with DLS, the compatibility of FA with WGS, the mixture of GGBS with PFA, blending of GGBS with CKD, etc. are studied and reported. The elemental composition, pore size distribution system and microstructural composition were studied through X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) and discussed. The results of the study revealed that a combination of GGBS and PFA yields better results than the reference mixes made of cement and other blended mixes made of SCMs. The performance of CW and WGS is found good at the later age. The performance of fly ash on mortar properties depended on the dosage and fineness of fly ash. Apart from their better solo performance, a combination of limestone dust and silica fume not only enhances the strength but also the sulphate resistance of mortar. The study revealed that the use of SCMs in mortar contributes to a reduction in cement production and carbon emission.

Examining the use of Lime and Gypsum in GGBS based alkali activated concrete

Alkali Activated Concrete (AAC) using Ground Granulated Blast Furnace Slag (GGBS) and Fly ash as precursors attracted several researchers in developing no cement concretes. Use of Fly ash as precursor needs high temperature for curing. GGBS as precursor avoids temperature curing, but setting is too fast to accept or compare with conventional or ordinary Portland Cement. Many researchers have used the combination of GGBS and Fly ash as precursor in developing AAC. Lime resources are plentily available, and use of lime be encouraged for developing sustainable concretes. Thus, an attempt has been made to examine the use of lime to some extent in the AAC. The present paper examines the use of lime and gypsum along with GGBS and metakaolin as precursor in developing AAC. 4 M Sodium hydroxide and sodium silicate solution is used as alkaline activator. Consistency, setting times and compressive strength of these mixes are reported. It is found that lime and gypsum addition has increased the consistency as well as setting times. It is suggested that precursor with 75% GGBS, 20% Metakaolin and 5% Lime showed good compressive strength. Addition of gypsum lowered the compressive strength of the mix.

Wet-Dry Cycles and Microstructural Characteristics of Expansive Subgrade Treated with Sustainable Cementitious Waste Materials.

This work presents an experimental study on the physico-mechanical and microstructural characteristics of stabilised soils and the effect of wetting and drying cycles on their durability as road subgrade materials. The durability of expansive road subgrade with a high plasticity index treated with different ratios of ground granulated blast furnace slag (GGBS) and brick dust waste (BDW) was investigated. Treated and cured samples of the expansive subgrade were subjected to wetting-drying cycles, California bearing ratio (CBR) tests, and microstructural analysis. The results show a gradual reduction in the California bearing ratio (CBR), mass, and the resilient modulus of samples for all subgrade types as the number of cycles increases. The treated subgrades containing 23.5% GGBS recorded the highest CBR value of 230% under dry conditions while the lowest CBR value of 15% (wetting cycle) was recorded for the subgrade treated with 11.75% GGBS and 11.75% BDW at the end of the wetting-drying cycles, both of which find useful application in road pavement construction as calcium silicate hydrate (CSH) gel was formed in all stabilised subgrade materials. However, the increase in alumina and silica content upon the inclusion of BDW initiated the formation of more cementitious products due to the increased availability of Si and Al species as indicated by EDX analysis. This study concluded that subgrade materials treated with a combination of GGBS and BDW are durable, sustainable and suitable for use in road construction.

Effects of modified binders on flowability of grout and properties of preplaced aggregate concrete

In preplaced aggregate concrete (PAC), it is important yet complex to achieve a grout with high flowability and bleed resistance simultaneously. Supplementary cementitious materials, typically incorporated to impart desired properties to concrete and to complement economic and environmental benefits, may uniquely alter the properties of PAC to that of conventional concrete. Therefore, comprehensive knowledge of incorporating supplementary cementitious materials, considering alterations in their flowability and constituent materials to improve the overall performance of PAC is essential. The present study investigates the properties of PAC, incorporating ground granulated blast furnace slag (GGBS) and silica fume (SF) as partial replacement of cement at 0–40% and 0–10%, respectively. Different proportions of GGBS and SF were considered, where, flowability and superplasticizer dosage were varied with and without incorporating sand. Grout properties were evaluated in terms of flowability and compressive strength and PAC properties were evaluated in terms of mechanical strength, durability, and dimensional stability. The findings revealed that the combination of GGBS and SF in grout displayed suitable flowability and acceptable strength. Removal of sand from grout improved the properties of grout while deteriorating the properties of PAC. PAC produced using grout with 10% SF and sand to binder ratio of 0.5, exhibiting efflux time of less than 20 s, displayed the highest compressive strength. GGBS and SF significantly improved chloride ion penetration of PAC with the drawback of increased drying shrinkage. Nevertheless, all PAC mixes could still be classified as low shrinkage concrete. PAC produced with 40% GGBS and 10% SF exhibited comparable compressive strength and enhanced resistance to chloride ion penetration to that of PAC without GGBS/SF.

Compressed unfired blocks made with iron ore tailings and slag

Growing demand for houses in urban India has increased the requirements for construction materials such as clay fired bricks and cement blocks. At the same time, conventional practice of brick manufacturing is not environment friendly due to high energy consumption and CO2 emissions during various stages of its production. Therefore, recent trend in research has been directed towards utilization of various industrial wastes and methods, which emerge as sustainable alternatives for environmental concerns arising in the construction industry. This study focused on utilizing mining waste, namely iron ore tailing (IOT) in development of stable blocks. It has reported various properties of compressed unfired blocks formed by IOT and ground granulated blast furnace slag (GGBS) in varying proportions and with a fixed amount of lime. The combination of GGBS and lime was found to be suitable in stabilizing IOT towards block production. Furthermore, a maximum compressive strength of 7.7 MPa was achieved for blocks after 28 days of air curing. Also, the addition of GGBS has reduced the water absorption and apparent porosity of the IOT blocks, confirming the positive interaction between IOT, GGBS and lime. It also indicates the prospective of blended binders in improving the compactness of the blocks, which will have direct influence on the durability and service life of the blocks. Finally, the results show that most of the developed blocks satisfy the requirement of IS 1077 specification and can be used in various applications such as load and non-load bearing walls, framed structures, foundations and pedestrian walkways.

Multi-criteria feasibility of real use of self-compacting concrete with sustainable aggregate, binder and powder

Replacing natural raw materials with industrial by-products can increase the sustainability of Self-Compacting Concrete (SCC), although its fresh and hardened behavior will usually worsen. The benefits of increased sustainability must therefore outweigh any reduction in concrete flowability and strength. These aspects can be analyzed through Multi-Criteria Decision-Making (MCDM) algorithms. In all, 19 SCC mixes were studied. One reproduced commercial SCC (limestone filler and conventional cement), the others were produced with more sustainable materials: 100% coarse Recycled Concrete Aggregate (RCA); 0%, 50% or 100% fine RCA; 45% Ground Granulated Blast-furnace Slag (GGBS); and sustainable aggregate powders such as limestone fines 0/0.5 mm and RCA powder 0/0.5 mm. Decreased flowability at 15 and at 60 min, compressive strength, modulus of elasticity, carbon footprint, and cost of mix were all studied. Both the carbon footprint and the cost were calculated considering only the composition of the SCC, without including aspects that depend on each particular case study, such as transport distances. These aspects constituted the decision-making criteria of the MCDM analysis, under which 14 scenarios were evaluated with different requirements for SCC, using 3 different algorithms (TOPSIS, AHP, and PROMETHEE). The results suggested that the ideal choice for fast concreting is a combination of GGBS, 100% coarse RCA and limestone fines, although if SCC has to be transported to the concreting point, then conventional cement should be used. Strength and stiffness can be maximized by limiting the fine RCA content to 50%. Finally, considering a versatile choice, only SCC with coarse RCA, limestone fines, GGBS and 0% fine RCA could compete with conventional SCC. Adapting the design to minimize the detrimental effects of by-products is therefore essential to promote sustainable SCC that is also commercially competitive.

The bond strength of self-compacting concrete exposed to elevated temperature

Self-compacting concrete (SCC) is a flowable concrete that can flow, fill and pass through congested area of reinforcement without segregation. As a material used in massive constructions, understanding of the effects of elevated temperature exposure on the properties of SCC is vital. The bond between concrete and embedded steel, which degrades with an increase in temperature, influences the load-carrying capacity and thus the fire resistance of reinforced concrete elements. The objective of this study was to evaluate the bond strength of SCC specimens made with fly ash, ground granulated blast-furnace slag (GGBFS) and expanded perlite aggregate (EPA) under elevated temperature exposure. EPA was introduced to enhance the fire endurance of the SCC. Slump flow, J-ring and V-funnel tests were conducted as per EFNARC guidelines to check the rheological characteristics of SCC. Specimens were exposed to elevated temperature following the ISO 834 standard fire curve. Pull-out tests were carried out to determine the bond strength of reference SCC specimens and specimens exposed to elevated temperature. Data from the tests showed that the SCC specimens made with a combination of GGBFS and EPA exhibited improved bond strength, both at room and elevated temperatures.

Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

Incorporation of a nanotechnology-based product in cementitious binders for sustainable mitigation of sulphate-induced heaving of stabilised soils

Sulphate-induced heaving in soils is a common problem caused mostly by the use of calcium-based binders in the stabilisation of sulphate-bearing soils. Sulphate-induced heaving is attributed to precipitation and growth of ettringite minerals in a high alkaline environment. A sustainable means of reducing sulphate-induced heaving by the addition of an additive called “RoadCem” (RC) to soils stabilised by calcium-based cementitious products has not been studied. RoadCem (RC) is an additive that is manufactured based on nanotechnology and comprises synthetic zeolite, alkaline metals and some complex activators as some of its constituents. This research is therefore concerned with the performance of a sulphate-bearing soil stabilised by partially substituting cement (CEM I) with ground granulated blast furnace slag (GGBS) and incorporation of marginal quantities of RC. Laboratory studies including oedometer free swelling testing, unconfined compressive tests and microstructural analyses of the phases of hydration in the stabilised soils were carried out. Results indicated a reduction in heave by about 67% when 1% of RC was included in the cementitious mix with 50% of the CEM I replaced by a combination of GGBS and RC. The use of RC in the stabilised soil was even more promising than that in which only GGBS was utilised to replace half of the CEM I proportion in the stabilised soil with the result indicating almost a 30% difference in heave reduction. Results also indicated an increase in the unsoaked strength of stabilised soil with RC inclusion compared to the stabilised mix without RC. Scanning electron micrograph studies revealed almost a complete elimination of heave-causing ettringite minerals under a 28-day hydration phase of the stabilised soil when using RC.

Effect of nano silica on the properties of slag concrete

As a sustainable approach to reduce greenhouse gases emission during cement production and waste generation from steel manufacturing industry, ground granulated blast furnace slag (GGBFS) has been widely used as a cement replacement material for concrete production. However, due to its low pozzolanic activity, GGBFS causes delay in early strength development leading to prolonged curing of concrete. In this study, the influence of nanosilica (Ns), a highly reactive pozzolan on the properties of GGBFS concrete was examined. Different concrete samples containing intermixed GGBFS (0-30%) and Ns (0-3%) by weight were produced. The workability, setting time, compressive strength, tensile strength, water absorption and sorptivity of the samples were tested. The results show that the addition of nanosilica improves compressive strength and tensile strength of the GGBFS concrete. Therefore, the combination of GGBFS and Ns can be used for the production of good quality

Air-Cured Alkali Activated Binders for Concrete Pavements

The present study focuses on the possibility of use of alkali activated binders for use in concrete pavements. Alkali Activated Slag Concrete (AASC) and Alkali Activated Slag Fly ash Concrete (AASFC) are prepared and the properties are compared with Ordinary Portland Cement Concrete (OPCC). The Ground Granulated Blast Furnace Slag (GGBFS) and Fly Ash (FA) are blended in the ratios 100:0, 75:25, 50:50 and 25:75 as binder and activated using strong alkaline solution. Trial mixes are carried out to identify the optimal Activator Modulus (Ms) for each combination of GGBFS and FA. The mix design for the optimal activator modulus is optimised to achieve sufficient strength for Pavement Quality Concrete (PQC) and the fresh and mechanical properties are studied in detail. The results indicate the properties of AASC and AASFC are similar or slightly better than conventional OPCC and satisfy the minimum strength requirements for concrete pavements. The application of alkali activated binders will minimise the environmental hazards occurring from augmented OPC production, along with effective utilisation of industrial waste materials and conservation of natural resources.

The performance of blended conventional and novel binders in the in-situ stabilisation/solidification of a contaminated site soil

This paper presents an investigation of the effects of novel binders and pH values on the effectiveness of the in-situ stabilisation/solidification technique in treating heavy metals and organic contaminated soils after 1.5-year treatment. To evaluate the performance of different binders, made ground soils of SMiRT site, upto 5m depth, were stabilised/solidified with the triple auger system and cores were taken for laboratory testing after treatment. Twenty four different binders were used including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fuel ash (PFA), MgO and zeolite. Unconfined compressive strength (UCS), leachate pH and the leachability of heavy metals and total organics were applied to study the behaviours of binders in treating site soils. Under various contaminant level and binder level, the results show that UCS values were 22–3476kPa, the leachability of the total organics was in the range of 22–241mg/l and the heavy metals was in the range of 0.002–0.225mg/l. In addition, the combination of GGBS and MgO at a ratio of 9:1 shows better immobilisation efficiency in treating heavy metals and organic contaminated soils after 1.5-year treatment, and the binding mechanisms under different binders were also discussed in this paper.

Rice husk ash as both pozzolanic admixture and internal curing agent in ultra-high performance concrete

The present study investigated the effects of mesoporous amorphous rice husk ash (RHA) on compressive strength, portlandite content, autogenous shrinkage and internal relative humidity (RH) of ultra-high performance concretes (UHPCs) with and without ground granulated blast-furnace slag (GGBS) under different treatments. The results were compared with those of UHPCs containing silica fume (SF). Because of the mesoporous structure, RHA can absorb an amount of aqueous phase to decrease the free water content and to supply thereafter water for further hydrations of cementitious materials. Hence, compressive strength of RHA-blended samples is enhanced. The highly water absorbing RHA delays and slows down the decrease in the internal RH (self-desiccation) of UHPCs, and hence strongly mitigates autogenous shrinkage of UHPCs compared to SF. The combination of GGBS and RHA or SF improves the properties of UHPC. These results suggest that RHA acts as both highly pozzolanic admixture and internal curing agent in UHPC.

To Study The Partial Replacement Of Cement By FA & RHA And Natural Sand By Quarry Sand In Concrete

Concrete is the most widely used construction material in civil engineering industry because of its high structural strength and stability. The concrete industry is constantly looking for supplementary cementitious material with the objective of reducing the solid waste disposal problem. Ground granulated blast furnace slag (GGBS) Rice husk ash (RHA) and Quarry sand (QS) are among the solid wastes generated by industry. To overcome from this crisis, partial replacement of natural sand (NS) with Quarry sand and partial replacement of cement with GGBS and RHA can be an economic alternative. This research is carried out in three phase, in first phase mix of M40 grade concrete with replacement of 0%,15%,30%,45%,60%,75%,90% and 100% of quarry sand with natural sand is carried out to determine the optimum percentage of replacement at which maximum compressive strength is achieved. It is observed that when natural sand is partially replaced with 60% quarry sand maximum strength is achieved. In second phase, cement is partially replaced with GGBS by 10%, 20% and 30%. In phase three, combination of GGBS and RHA is partially replaced with cement. The composition of 22.5% GGBS + 7.5% RHA with 60% of quarry sand gives good strength results.

Mitigation of Detrimental Effects of Alkali-Silica Reaction in Cement-Based Composites by Combination of Steel Microfibers and Ground-Granulated Blast-Furnace Slag

The effect of combining brass-coated steel microfiber and ground-granulated blast-furnace slag (GGBS) on the mitigation of deleterious expansion due to alkali-silica reaction (ASR) was investigated in this research. A potentially reactive basaltic aggregate was chosen as a reactive material. Two series of specimens containing different amounts of microfiber were prepared. One of them was cured in 1 M NaOH solution at 80°C to obtain a similar maturity; the other series was cured in 80°C water up to 120 days. ASR expansion, strength development, and toughness properties were observed for 120 days in NaOH solution and the results were compared with specimens kept in water. Test results indicate that the combination of GGBS and steel fibers reduced ASR expansion significantly. Furthermore, the combination was very effective at preventing the mechanical property loss due to ASR, such as flexural strength, compressive strength, and toughness. Microstructural investigations revealed that the reaction products had a different morphology (e.g., fibrous, network appearance) when the specimens were kept in NaOH solution.