Ground Granulated Blast Furnace Slag Replacement Research Articles

Performance of reinforced concrete beams cast with different percentages of GGBS replacement to cement

The aim of this paper is to study the effect of using Ground Granulated Blast Furnace Slag (GGBS) as a partial replacement to cement in reinforced concrete (RC) beams. A total of eight beams were cast with different percentages of GGBS replacement of 0%, 50%, 70%, and 90%, respectively. The performance of the tested specimens were evaluated and compared to that of a control beam without GGBS (0%). In addition, the concrete compressive and tensile strength of the different concrete mixes were evaluated and compared. Overall, test results indicated that the compressive and tensile strength of the different mixtures were quite similar. In addition, the performance of RC beams with GGBS replacement up to 70% is similar to that without GGBS. However, the stiffness and strength for the beam specimens with 90% GGBS were lower than that without GGBS by 16% and 6%, respectively. It was also concluded that the use of high percentage of GGBS up to 70% as a replacement to cement is practical and will not comprise the performance of RC beams. Furthermore, such replacement will contribute to the reduction in CO2 emission (carbon footprint) and therefore encourage the use of such sustainable and green concrete.

Effect of GGBS and curing temperature on microstructure characteristics of lightweight geopolymer concrete

Cement replacement by supplementary cementitious materials has been gaining momentum as a sustainable mechanism to reduce greenhouse gas emissions while also recycling industrial by-products. This paper presents the development and microstructure characterization of fly ash-based lightweight geopolymer concrete incorporating ground granulated blast furnace slag (GGBS). Concrete samples were prepared with 0%, 25% and 50% GGBS replacement and cured at 30°C, 60°C, and ambient temperature. While dune sand and lightweight expanded clay were used as aggregates, a mixture of sodium silicate and sodium hydroxide served as the alkaline activation solution. Microstructure evaluation was carried out at 7 and 28 days employing scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Residual fly ash and GGBS were identified in the concrete and bonded to geopolymeric reaction products. The microstructure highlighted the formation and coexistence of aluminosilicate hydrate and aluminum-rich calcium silicate hydrate with traces of sodium. Subsequent polymerization was also verified by an increase in FTIR and DSC peaks.

Estimation of Corrosion-Free Life for Concrete Containing Ground Granulated Blast-Furnace Slag under a Chloride-Bearing Environment

The rate of chloride transport by diffusion in concrete containing ground granulated blast-furnace slag (GGBS) was mathematically estimated to predict the corrosion-free service life of concrete structures exposed to seawater environment. As a factor to corrosiveness of steel embedment, replacement ratio of GGBS was selected, accounting for 25 and 50% to total binder. As a result, it was found that an increase in the GGBS content resulted in an increase in the chloride binding capacity, which would give rise to a lower chloride diffusion rate, thereby reducing the risk of chloride-induced corrosion. When it comes to the sensitivity of parameters to service life, the effective diffusivity showed a marginal influence on serviceability, irrespective of GGBS contents while surface chloride content and critical threshold concentration revealed more crucial factors to long term chloride diffusion. As the GGBS replacement increased, the variation in service life has become less influential with changing parameters. Substantially, GGBS concrete at high replacement ratio enhanced the service life due to a combination of dense pore structure and enhanced chloride binding capacity.

Studies on Punching Shear Resistance of Two Way Slab Specimens with Partial Replacement of Cement by GGBS with Different Edge Conditions

The present work is an effort to quantify the punching shear load resistance effect on two way simply supported slab specimens with replacement of cement by Ground Granulated Blast Furnace Slag (GGBS) with different edge conditions at various replacement levels and evaluate its efficiency. GGBS replacement has emerged as a major alternative to conventional concrete and has rapidly drawn the concrete industry attention due to its cement savings, cost savings, environmental and socio-economic benefits. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. The slab specimens were cast using M30 grade concrete with HYSD bars. The cement was partially replaced with GGBS at different percentages i.e., 0 to 30 % at regular intervals of 10 %. The test results indicate that the two way slab specimens with partial replacement of cement by GGBS exhibit high resistance against punching shear when compared with conventional concretes slab specimens.

Material and structural properties of waste-oil palm shell concrete incorporating ground granulated blast-furnace slag reinforced with low-volume steel fibres

This paper presents the utilization of low-volume steel fibres to improve the performance of concrete containing waste oil palm shell as aggregate and ground granulated blast furnace slag (GGBS) as partial cement replacement material. The experimental results showed that although the increased GGBS replacement level caused a lowering of the concrete properties, the addition of low-volume steel fibres improved the material properties, such as the mechanical properties, stress–strain behaviour and flexural toughness of the oil palm shell concrete (OPSC). In terms of these properties, it was found that the combination of 20% GGBS as partial cement replacement and 0.6% steel fibres achieved the best results among the concrete mixtures tested. The mix was then used for the investigation of the structural behaviours (bond and flexural behaviours) in comparison with conventional concrete and plain OPSC. The results showed that the OPSC containing 0.6% steel fibres enhanced the structural performance compared to the corresponding OPSC without fibres as well as the ready-mixed grade 30 normal weight concrete.

Development of geopolymer mortar under ambient temperature for in situ applications

Geopolymer concrete technology involves production of more environmentally friendly waste material-based concrete which could be a viable solution for conventional concrete replacement. Typical fly ash-based geopolymer concrete however requires high temperature curing treatment in order to develop sufficient early strength properties, which is considered a severe limitation for cast-in-place concrete applications. Most previous studies on geopolymer concrete have focused on the properties of concretes pre-hardened by heat curing and/or by aggressive chemical treatment (e.g. alkali activation using concentrated sodium hydroxide (NaOH)). The current study presents an extensive experimental investigation on the mechanical and microstructural properties of geopolymer concrete mixes prepared with a combination of fly ash and slag cured under ambient temperature. ‘User friendly’ geopolymer mixes were produced using fly ash (FA) and Ground Granulated Blast furnace Slag (GGBS) mixed together with potassium silicate with molar ratio equal to 1.2 (as the activator) and water. The results indicated that heat curing treatment can be avoided by partial replacement of fly ash with slag. The compressive strength of the examined mixes was found to be in the range of 40–50MPa for 40% and 50% GGBS replacement mixtures respectively. Moreover, the flexural and direct tensile strengths of geopolymer mixes are considerably improved as the GGBS content is increased. Based on FTIR and SEM/EDS analysis, the inclusion of a higher content of GGBS resulted in a denser structure by formation of more hydration products.

Study on Properties of SCC with Partial Replacement of Cement by GGBFS and Fly Ash

This paper presents experimental study on the properties of self-compacting concrete (SCC) amended with two additional cementitious materials (fly ash and slag) on the mechanical performance of self-compacting concrete (SCC). Portland cement (PC) was replaced with fly ash (FA), Ground Granulated Blast Furnace Slag (GGBFS). The effect of these admixtures on the fresh and hardened SCC of various mix proportions was studied. It was observed there was only very small difference in workability and strength of SCC when the cement was partially (30%) replaced by GGBFS and Fly ash at various proportions. From the results obtained GGBFS replacement in concrete, considerably increase the strength of concrete.

Characterisation of high-performance cold bitumen emulsion mixtures for surface courses

Cold bitumen emulsion mixture (CBEM) is not yet widely used as a surface course around the world. In this study, 0/14-mm-size dense-graded surface course CBEMs have been investigated. The mechanical performance was evaluated in terms of stiffness modulus over 3 months and resistance to permanent deformation under three different stress levels (100, 200, 300 kPa), whilst durability evaluation was carried out in terms of resistance to moisture and frost damage. The study has also investigated the incorporation of low cement content (1%) with relatively sustainable by-product fillers, namely ground-granulated blast furnace slag (GGBS) and fly ash (FA) type 450-S on both mechanical and durability performance. A comparison has been carried out between the low and high cement content CBEM, as well as with respect to corresponding hot mix asphalt (HMA). The results revealed that the incorporation of GGBS and FA in CBEMs leads to superior performance, similar to CBEMs treated with high cement content and comparable to an equivalent HMA. Furthermore, GGBS replacement exhibited better performance than that of FA replacement. The findings suggest that the new sustainable types of CBEM can be developed for using as a surface layer for medium- to heavy-trafficked roads.

Effects of cold joint and loading conditions on chloride diffusion in concrete containing GGBFS

RC (Reinforced Concrete) structures undergo deterioration and the initiated corrosion in the steel is considered as one of the most critical problems. For efficient construction of structures, construction joint should be installed, however cold joint occurs reluctantly due to delayed concrete placing and poor condition of the old concrete surface. The chloride ingress in cold joint concrete is more rapid than that in sound concrete, and it is also affected by loading conditions. This paper presents a quantitative evaluation on chloride diffusion coefficient considering the effects of cold joint and loading conditions. For the work, concrete samples with 0.6 of w/b (water to binder) ratio are prepared. Compressive and tensile stresses are induced with 30% and 60% of ultimate strength, respectively. The chloride diffusion coefficients in accelerated condition are measured under loading, and the effects of cold joint and loading levels are evaluated. In order to investigate an effect of GGBFS (Ground Granulated Blast Furnace Slag) on chloride diffusion, 40% of GGBFS replacement ratio is considered for OPC (Ordinary Portland Cement) and the GGBFS effect is evaluated considering cold joint and loading levels. The effects of stress level, pore structure improvement through GGBFS, and cold joint on chloride diffusion coefficient are quantitatively investigated.

Abrasion resistance and mechanical properties of Roller Compacted Concrete with GGBS

In this experimental study, seven different mixtures of Roller Compacted Concrete (RCC) were adopted in which cement was partially replaced by six kinds of replacements (10%, 20%, 30%, 40%, 50% and 60%) of Ground Granulated Blast Furnace Slag (GGBS). The main objective of this experimental work was to investigate the effect of GGBS on the mechanical properties and abrasion resistance of RCC. Flexural, compressive, split tensile strength and abrasion resistance tests (Cantabro test and abrasion resistance with rotating cutter test) were conducted for the ages of 3days, 7days, 28days and 90days of curing. The strength values of RCC specimens were decreased for 3days when GGBS content increased. But at the age of 7days and 28days the strengths were considerably higher than control mix concrete up to 50% replacement of GGBS. Beyond 28days, the strength increases with the presence of GGBS up to 60% of replacement level. Also it was concluded that increasing GGBS content has increased abrasion resistance of RCC at all replacement levels. On the other hand there was a strong correlation exists between the GGBS content, weight loss with compressive, flexural and split tensile strength.

A probabilistic assessment of the influence of age factor on the service life of concretes with limestone cement/GGBS binders

The use of Supplementary Cementitious Materials (SCMs) in concrete manufacture has increased significantly in recent years. Utilising SCMs in the concrete mix reduces CO2 footprint while also generally enhancing durability. Time-dependent characteristics of concrete become more significant as SCM replacement levels increase. Service life modelling requires incorporation of accurate age factors; however limited research has been published on the influence of time-dependent characteristics of SCM concretes when manufactured with limestone cement (CEM II/A-LL). In this study, mix-specific age factors were determined based on the chloride diffusivity of concretes produced using a limestone cement binder with varying replacement levels of ground granulated blast-furnace slag (GGBS). The experimentally-determined age factors were validated against field data. Application of the validated factors in service life assessment models indicated increased sensitivity of the models to increased GGBS replacement level while affirming the enhanced durability effect of GGBS when used in combination with limestone cement.

A study of engineering and electricity properties of cement mortar added with recycled materials and piezoelectric powders

Due to increasing global energy saving, carbon reduction, environmental considerations, and the environmental change resulting from the greenhouse effect, and because Taiwan is located on the plate junction, where earthquakes frequently occur, and because there is an abundance of rainfall during typhoon season, which often cause natural disasters, it is necessary to enhance the disaster prevention of buildings. This study uses recycled materials (fly ash, ground granulated blast furnace slag (GGBFS), and waste Liquid Crystal Display (LCD) glass powder) and Pd-Zr-Ti piezoelectric (PZT) to enhance intelligent functions of original substrates. The volumetric method is used for the design. The control group uses recycled materials to replace cement [0%, 10%, 20%, and 30%]. The PZT group uses a PZT powder to replace 5% of fine aggregates to make cement mortar to test the correlation between engineering and electricity properties of flow, compressive strength, water absorption, ultrasonic pulse velocity (UPV) and resistivity (electricity at 50V and 100V). The mechanical and electrical effects of cement mortar of various groups are discussed to determine the correlation between impedance characteristics and mechanical behavior of cement mortar in different electrical field environments and aqueous states, to build an engineering-electricity relation database for recycled materials and PZT, and to determine the relationships between various variables. A pozzolanic reaction occurs in GGBFS after 7days. A 30% GGBFS replacement (32.9MPa) has the maximum compressive strength. A 20% waste LCD glass powder replacement (31.8MPa) can fill up finer pores and accelerate hydration. The addition of GGBFS and waste LCD glass powder reduces water absorption and internal porosity. Water absorption increases when fly ash is replaced. The resistivity at 50V is higher than resistivity at 100V in an electrical field environment. Specifically, in a high voltage environment, the resistivity generated during the delivery process is reduced. Because the voltage increase improves conductivity inside the specimen, the resistivity is reduced. The resistivity increases in correlation with compressive strength in the SSD state of fly ash and GGBFS. The resistivity decreases when the compressive strength increases in the OD state. The resistivity increases when the waste LCD glass powder is replaced in SSD and OD states.

MECHANICAL AND DURABILITY PROPERTIES OF SLAG BASED RECYCLED AGGREGATE CONCRETE

In this paper, the possibility of using recycled aggregate (RA) and ground granulated blast furnace slag (GGBFS) to produce a structural concrete was studied by compromising strength to a lesser extent. Hence an attempt has been made to study the strength and durability characteristics of the GGBFS-based recycled aggregate concrete. Four different groups of mixes were designed by replacing natural coarse aggregate (NA) 0, 25, 50 and 100% with recycled coarse aggregates. In each group the effect of RA was studied by replacing cement with GGBFS in different percentages from 20 to 50% with an increment of 10%. The effects of RA and GGBFS on fresh and hardened concrete properties were studied and the results were compared with natural aggregate concrete (NAC) and optimum replacement of RA and GGBFS was also found. Experimental results indicate that increase in concrete strength for all NA replacements with RA for GGBFS concrete upto 40% at the age of 90 days and further addition of GGBFS shows reverse trend.

Compressive behaviour of lightweight oil palm shell concrete incorporating slag

In this paper, the investigation of the compressive behaviour of lightweight oil palm shell concrete (OPSC) containing ground granulated blast furnace slag (GGBS) was carried out. The variables studied include the compressive strength class (grade 25, 35 and 45), curing method (air and water curing) and GGBS replacement level (20% and 60%). Higher GGBS content and air curing resulted in lower mechanical properties such as compressive strength and modulus of elasticity (MOE) of the concrete. Analysis revealed that when the experimental stress–strain parameters such as the peak stress, strain at peak stress and MOE were incorporated into Popovics stress–strain model, the compressive stress–strain relationship of the lightweight concrete could be well-estimated.

Assessing some durability properties of sustainable lightweight oil palm shell concrete incorporating slag and manufactured sand

This paper explores some of the durability properties of a sustainable concrete utilizing oil palm shell (OPS), which is a waste material from the palm oil industry, as lightweight coarse aggregate and manufactured sand to replace conventional natural mining sand as fine aggregate. Ground granulated blast furnace slag (GGBS) was used at 20%, 40% and 60% cement replacement levels with the aim of reducing the cement consumption in OPS concrete (OPSC) and the effect of the GGBS on the water absorption, sorptivity and the long-term free shrinkage of OPSC was investigated. The use of GGBS was found to reduce the sorption of OPSC as the 90-d sorptivity values fell in the range of 0.047–0.065 mm/min0.5, compared to 0.091 mm/min0.5 for mixes without GGBS. The OPSC containing GGBS was also found to have initial water absorption of below 3%, which indicated good quality of concrete. In the long term study, over a period of 365 d, the free shrinkage of the OPSC with up to 40% GGBS replacement level was comparable to the corresponding OPSC without GGBS. The GGBS was also found to be beneficial in enhancing the long term compressive strength gain as well as lowering the strength decrease of OPSC upon heat exposure.

Influence of Molarity and Chemical Composition on the Development of Compressive Strength in POFA Based Geopolymer Mortar

The investigation concerns the use of the optimum mix proportion of two locally available pozzolanic waste materials, namely, ground granulated blast furnace slag (GGBS) and palm oil fuel ash (POFA), together with metakaolin (MK) as binders. In addition, another local waste material, manufactured sand (M-sand), was used as a replacement for conventional sand in the development of green geopolymer mortar. Twenty-four mortar mixtures were designed with varying binder contents and alkaline activators. The oven dry curing was also kept consistent for all the mix proportions at a temperature of 65°C for 24 hours. The highest 28-day compressive strength of about 48 MPa was obtained for the mortar containing 20% of MK, 35% of GGBS, and 45% of POFA. The increment of MK beyond 20% leads to reduction of the compressive strength. The GGBS replacement beyond 35% also reduced the compressive strength. The entire specimen achieved average 80% of the 28-day strength at the age of 3 days. The density decreased with the increase of POFA percentage. The finding of this research by using the combination of MK, GGBS, and POFA as binders to wholly replace conventional ordinary Portland cement would lead to alternate eco-friendly geopolymer matrix.

Time Dependency on Chloride Diffusion of Ceramic Waste Aggregate Mortars Containing Ground Granulated Blast-Furnace Slag

From our previous findings, the recycling of ceramic waste aggregate (CWA) in mortar has been proved an ecological means plus an excellent outcome against chloride ingress. The CWAs were electric porcelain insulator wastes supplied from an electric power company, which were crushed and ground to fine aggregate sizes. In this study, to further develop the CWA mortar as an eco-efficient, ground granulated blast-furnace slag (GGBS) was incorporated. The GGBS was utilized as a supplementary cementitious material (SCM) at three different replacement levels of 15, 30, and 45% by weight of cement. The time dependency of the GGBS on enhancing chloride resistance in the CWA mortars was experimentally assessed by using an electron probe microanalysis (EPMA). The tests were carried out on mortar samples after immersion in 5.0% NaCl solution for 24, 48, and 96 weeks. Another set of the mortar samples was exposed to a laboratory ambient condition for 24, 48, and 96 weeks and then followed with a carbonation test. The resistance to the chloride ingress of the CWA mortar becomes more effective in proportion to the replacement level of the GGBS. Meanwhile, the carbonation depth of the CWA mortar increases with increasing the GGBS. The relationship between the apparent chloride diffusion coefficient and the GGBS replacement level was shown along with the immersion time.

Effect of early-age freeze-thaw exposure on the mechanical performance of self-compacting repair mortars

Abstract Self-compacting repair mortar (SCRM) is a functional material for repair or retrofit applications. Industrial byproducts, such as fly ash (FA) or ground granulated blast furnace slag (GGBFS), can be used to reduce cement dosage and to obtain an eco-friendly material. However, these waste materials may cause durability problems at early ages as a result of curing sensitivity. In this study, the effects of high-volume FA and GGBFS replacement on early-age freeze-thaw (F-T) resistance of SCRM with and without steel microfibers were investigated. The mechanical properties, including fracture energy, were determined after F-T cycles. The fresh state properties and volume stability of the hardened specimens were studied. The results demonstrated that prolonged curing is essential to avoid the loss in mechanical properties due to F-T exposure. SCRM containing high-volume byproducts seem vulnerable to the effect of F-T at early ages, and this negative effect cannot be overcome with steel microfibers.

ELEVATED TEMPERATURE RESISTANCE CONCRETE USING NON-TRADITIONAL MATERIALS

The properties of materials used in preparing concrete play an important role on the performance of concrete during its lifetime. Concrete generally provides adequate fire resistance for most applications. However, the strength and durability properties of concrete are significantly affected when subjected to elevated temperature. Terrorist attack, accidental fire breakout and different type of explosions produce a rapid change of temperature for a short period. This study was focused on improving the elevated temperature resistance of normal concrete by using Ground Granulated Blast Furnace Slag (GGBFS) as cement replacement and fine aggregate replacement and Brick Break (BB) as coarse aggregate replacement. Different replacement percentages of GGBFS and BB were used in this study (10%, 20% and 30%). Percentage of GGBFS replacement was calculated based on the dry weight of cement material, while the percentage of BB was calculated based on the weight of coarse aggregate. Nine mixes in additional to the reference concrete mix (25 MPa) considered in this study were exposed to high temperatures of 300, 600 and 800°C. Moreover, cooling system effect of heated concrete cubes have been investigated through two cooling procedure [Air cooling and Water cooling (quenching)].Physical and mechanical properties of the developed mixes including residual compressive strength, mass losses, adsorption, and water absorption have been determined. Test data indicated that high temperature caused significant deterioration in the properties of concrete; the addition of GGBFS and BB could all effectively improve the residual compressive strength of concrete. For all series there is decrease in compressive strength with increase in temperature this decrease reached to 50% for control mix at 800°C in case of slow cooling in air, however the residual compressive strength was 65 and 60% for mixes containing GGBFS and BB respectively

Influence of Iranian low-reactivity GGBFS on the properties of mortars and concretes by Taguchi method

Ground Granulated Blast Furnace Slag (GGBFS) is widely used as an effective partial cement replacement material. GGBFS inclusion has already been proven to improve several performance characteristics of concrete. GGBFS provides enhanced durability, including high resistance to chloride penetration and protection against alkali silica reaction. In this paper results of an experimental research work on influence of low-reactivity GGBFS (which is largely available in Iran) on the properties of mortars and concretes are reported. In the first stage, influence of GGBFS replacement level and fineness on the compressive strength of mortars was investigated using Taguchi method. The analysis of mean (ANOM) statistical approach was also adopted to develop the optimal conditions. Next, based on the obtained results, concrete mixtures were designed and water penetration, capillary absorption, surface resistivity, and compressive strength tests were carried out on highstrength concrete specimens at different ages up to 90 days. The results indicated that 7-day compressive strength is adversely affected by GGBFS inclusion, while the negative effect is less evident at later ages. Also, it was inferred that use of low-reactivity GGBFS (at moderate levels such as 20% and 30%) can enhance the impermeability of high-strength concrete since 28 days age.