Geopolymer Concrete Columns Research Articles

Behavior of Quarry Rock Dust, Fly Ash and Slag Based Geopolymer Concrete Columns Reinforced with Steel Fibers under Eccentric Loading

Geopolymer concrete, also known as an earth-friendly concrete, has been under continuous study due to its environmental benefits and a sustainable alternative to conventional concrete construction. The supplies of many source materials, such as fly ash (FA) or slag (SG), to produce geopolymer concrete (GPC) may be limited; however, quarry rock dust (QRD) wastes (limestone, dolomite, or silica powders) formed by crushing rocks appear virtually endless. Although significant experimental research has been carried out on GPC, with a major focus on the mix design development, rheological, durability, and mechanical properties of the GPC mixes; still the information available on the structural behavior of GPC is rather limited. This has implications in extending GPC application from a laboratory-based technology to an at-site product. This study investigates the structural behavior of quarry-rock-dust-incorporated fiber-reinforced GPC columns under concentric and eccentric loading. In this study, a total of 20 columns with 200 mm square cross-section and 1000 mm height were tested. The FA and SG were used as source materials to produce GPC mixtures. The QRD was incorporated as a partial replacement (20%) of SG. The conventional concrete (CC) columns were prepared as the reference specimens. The effect of incorporating quarry rock dust as a replacement of SG, steel fibers, and loading conditions (concentric and eccentric loading) on the structural behavior of GPC columns were studied. The test results revealed that quarry rock dust is an adequate material that can be used as a source material in GPC to manufacture structural concrete members with satisfactory performance. The general performance of the GPC columns incorporating QRD (20%) is observed to be similar to that of GPC columns (without QRD) and CC columns. The addition of steel fibers considerably improves the loading capacity, ductility, and axial load–displacement behavior of the tested columns. The load capacities of fiber-reinforced GPC columns were about 5–7% greater in comparison to the CC columns. The spalling of concrete cover at failure was detected in all plain GPC columns, whereas the failure mode of all fiber-reinforced GPC columns is characterized with surface cracking leading to disintegration of concrete cover.

Improving the structural performance of reinforced geopolymer concrete incorporated with hazardous heavy metal waste ash

Purpose Demand for Geopolymer concrete (GPC) has increased recently because of its many benefits, including being environmentally sustainable, extremely tolerant to high temperature and chemical attacks in more dangerous environments. Like standard concrete, GPC also has low tensile strength and deformation capacity. This paper aims to analyse the utilization of incinerated bio-medical waste ash (IBWA) combined with ground granulated blast furnace slag (GGBS) in reinforced GPC beams and columns. Medical waste was produced in the health-care industry, specifically in hospitals and diagnostic laboratories. GGBS is a form of industrial waste generated by steel factories. The best option to address global warming is to reduce the consumption of Portland cement production and promote other types of cement that were not a pollutant to the environment. Therefore, the replacement in ordinary Portland cement construction with GPC is a promising way of reducing carbon dioxide emissions. GPC was produced due to an alkali-activated polymeric reaction between alumina-silicate source materials and unreacted aggregates and other materials. Industrial pollutants such as fly ash and slag were used as raw materials. Design/methodology/approach Laboratory experiments were performed on three different proportions (reinforced cement concrete [RCC], 100% GGBS as an aluminosilicate source material in reinforced geopolymer concrete [GRGPC] and 30% replacement of IBWA as an aluminosilicate source material for GGBS in reinforced geopolymer concrete [IGRGPC]). The cubes and cylinders for these proportions were tested to find their compressive strength and split tensile strength. In addition, beams (deflection factor, ductility factor, flexural strength, degradation of stiffness and toughness index) and columns (load-carrying ability, stress-strain behaviour and load-deflection behaviours) of reinforced geopolymer concrete (RGPC) were studied. Findings As shown by the results, compared to Reinforced Cement Concrete (RCC) and 100% GGBS based Reinforced Geopolymer Concrete (GRGPC), 30% IBWA and 70% GGBS based Reinforced Geopolymer Concrete (IGRGPC) (30% IBWA–70% GGBS reinforced geo-polymer concrete) cubes, cylinders, beams and columns exhibit high compressive strength, tensile strength, flexural strength, load-carrying ability, ultimate strength, stiffness, ductility and deformation capacity. Originality/value All the results were based on the experiments done in this research. All the result values obtained in this research are higher than the theoretical values.

Mathematical Formulation for Prediction of Structural Performance of Green Geopolymer Concrete Beams and Columns

In order to minimise the environmental impact of the waste and its disposal processes and to reduce global warming by cement production, this study has focused on the demand. This research looked at how waste wood ash can be used to make geopolymer concrete beams and columns, which can be used to replace traditional reinforced concrete elements in the construction industry. Waste wood ash, a waste produced in the nearby hotel and manufacturing factories by burning the waste wood collected in the woodworking industry and throwing the ash to land causing considerable environmental pollution. Geopolymer is an innovative inorganically friendly, alkaline-based binding agent that stimulates the source material of aluminosilicate (such as metakaolin, fly ash and GGBS). For three types of concretes (30 percent WWA – 70 percent Fly ash Geo-polymer concrete, Fly ash Geo-polymer concrete, and Reinforced Cement Concrete), the mathematical formula for the behaviour of beams in deflection, ductility factor, flexural strength, and columns in load carrying ability, stress strain behaviour, and load-deflection behaviours were investigated in this study. The results showed that the inclusion of waste wood ash into geopolymer concrete contributed to the 42 and 28 percent increase of the capacity for beam and column. Furthermore, by replacing waste wood ash, the compotation of structural elements was improved in their rigidity and ductility. The derived mathematical equations were most suitable for the prediction of forecast.

Data for Interaction Diagrams of Geopolymer FRC Slender Columns with Double-Layer GFRP and Steel Reinforcement

This article provides data of axial load-bending moment capacities of plain and fiber-reinforced geopolymer concrete (GPC, FRGPC) columns. The columns were reinforced by double layers of longitudinal and transverse reinforcement using steel and/or glass-fiber-reinforced polymer (GFRP) bars. The concrete fiber-reinforcing materials included steel and synthetic fibers. The columns data included different parameters like the longitudinal reinforcement ratio, the applied load eccentricity, and the columns’ slenderness ratio. The data was collected from different analysis output files then sorted and tabulated in usable formatted tables. The data can support the development of design axial load-bending moment interactions. In addition, further processing of the data can yield analytical strength curves which are useful in determining the columns stability under different structural loading configurations. Researchers and educators can make use of these data for illustrations and prospective new research suggestions.

Concentrically loaded recycled aggregate geopolymer concrete columns reinforced with GFRP bars and spirals

The increased quantity of construction and demolition waste and the high carbon footprint of cement production is creating significant environmental problems. This study explored the use of recycled coarse aggregates (RCA) in geopolymer concrete (GPC) and reinforced with glass fiber reinforced polymer (GFRP) bars and spirals to fabricate novel and structural GRAGC columns. A total of 9 GRAGC columns with 1150 mm in height and 250 mm in diameter were tested to failure under axial compression. The influence of a different number of longitudinal GFRP bars and spiral spacing on the cracking behaviour, ductility, and axial load-carrying capacity (LCC) were investigated. A nonlinear finite element model (FEM) was implemented to predict the axial compressive response of GRAGC columns. The experimental results depicted that an improvement in the ductility and lateral confinement was observed by decreasing the spacing of GFRP spirals. GRAGC columns with eight longitudinal GFRP bars portrayed the highest LCC. All tested GRAGC columns portrayed similar failure modes with the damage at the central region of the specimens. The theoretical model suggested over a database of 225 GFRP reinforced columns showed a high accuracy compared with the previous models. The present study suggests an efficient and environmental-friendly compression member.

Behavior of axially loaded plain and fiber‐reinforced geopolymer concrete columns with glass fiber‐reinforced polymer cages

AbstractIn this study, the behavior of axially loaded plain and fiber‐reinforced geopolymer concrete columns reinforced with glass fiber‐reinforced polymer (GFRP) bars and helices was investigated. Ten ambient‐cured geopolymer concrete columns of 160 mm diameter and 640 mm height were cast and tested under concentric axial loads. The behavior of the columns was investigated under the effect of the type of reinforcement (steel vs. GFRP), pitch of the GFRP helices (40, 75, 100 mm), and addition of nonmetallic fibers, that is, glass fiber and polypropylene fiber. It was found that GFRP bar reinforced geopolymer concrete column achieved less axial load, confinement efficiency, and ductility compared to the geopolymer concrete column reinforced with the same amount of the steel reinforcement. Overall, the reduction in the pitch of the GFRP helices enhanced the confinement efficiency, post‐peak behavior, and ductility of the plain and fiber‐reinforced geopolymer concrete columns. Also, the addition of fibers significantly improved the ductility of the GFRP bar reinforced geopolymer concrete columns.

Study a Structural Behavior of Eccentrically Loaded GFRP Reinforced Columns Made of Geopolymer Concrete

This study investigated a modern composite material, which is a short geopolymer concrete column (GPCC) reinforced by GFRP bars. The structural performances of GPCC subjected to eccentric load were studied and compared to the normal strength concrete column (NSCC) reinforced by steel bars. In this study, the primary experimental parameters were the reinforcement bars types, load eccentricity, and concrete types. Seven short columns were tested: three normal strength concrete columns reinforced by steel bars, three geopolymer concrete columns reinforced by GFRP bars and one normal strength concrete column without reinforcement. The model dimensions chosen in the present study was a square section of 130×130 mm and a total height of 850 mm. It was shown that the steel bars contribute about 16.47% of column capacity under concentric load. Comparing with the normal strength concrete column, a geopolymer concrete column reinforced by GFRP bars showed a little increase in ultimate load (5.17%) under concentric load. Under the load eccentricity of 130 mm, a geopolymer concrete column reinforced by GFRP bars showed a significant increase in the ultimate load (69.37%). Under large eccentricity, a geopolymer concrete column reinforced by GFRP bars has an outstanding effect on the columns' ultimate load capacity. Also, the sine form can be utilized for GPCC to find the lateral deflection along with the column high at different load values up to the failure.

Behaviour of GGBS-dolomite geopolymer concrete short column under axial loading

Geopolymer concrete was developed from Ground Granulated Blast furnace Slag (GGBS) and dolomite which are obtained from steel and rock industries. Optimum proportions of GGBS and dolomite were found out based on the maximum compressive strength. GGBS-Dolomite geopolymer concrete can reduce construction time and cost due to high early age strength. Experimental investigations were conducted to evaluate the behavior of GGBS-dolomite geopolymer concrete short columns under axial loading. GGBS-dolomite geopolymer concrete column showed better stress-strain behavior compared to cement concrete specimens. Load carrying capacity of geopolymer concrete specimens were improved by adding steel fibres at 0.25, 0.5 and 0.75% by volume of concrete. Ductility of geopolymer concrete was enhanced by 18%, 30% and 45% with the addition of steel fibres in the range of 0.25-0.75% by the volume of concrete. Parameters such as ultimate load, deflection, ductility and crack pattern of axially loaded short columns were evaluated using finite element method. It was observed that geopolymer concrete has 28% reduction in cost/ultimate load compared to ordinary concrete. GGBS-dolomite geopolymer concrete short columns without ductile detailing behaves similar to that of cement with ductile detailing (as per IS 13920-2016) with reduced cost/strength ratio.

Experimental study on reinforced geopolymer concrete columns using GGBS

Geopolymer concrete (GPC) is a type of concrete which is produced by using industrial by-products such as Ground Granulated Blast Furnace Slag (GGBS), Fly ash, Metakaolin and silica fumes etc. as binding materials which have cementitious properties. In this study Reinforced Geopolymer Concrete Columns (RGPC) are produced by using GGBS as binding material. GGBS is converted into binding material by using alkali activators such as Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3). RGPC columns of size 1000 mm × 150 mm × 150 mm were tested by altering the molarities of NaOH i.e. 8 M, 10 M, 12 M, 14 M and 16 M, size and Reinforcement ratio remains constant and these columns were tested for load carrying capacities, stress strain behaviour of GPC and load–deflection behaviours. The results showed that load carrying capacity of columns increases by increasing the molarity of NaOH and the deflection of the column is decreased by increasing molarity. The study revealed that GPC can be used in structural members like columns which have higher load carrying capacities.

P-MInteractions of Geopolymer Concrete Column Reinforced with and without Steel Fiber

<i>P</i>-<i>M</i>Interactions of Geopolymer Concrete Column Reinforced with and without Steel Fiber

A review of properties and behaviour of reinforced geopolymer concrete structural elements- A clean technology option for sustainable development

The traditional concrete is one of the most energy-intensive construction materials responsible for about 10% of global anthropogenic carbon dioxide emissions. Efforts are being made to develop an alternative binder for concrete. The geopolymer concrete (GPC) has emerged as a promising novel construction material for the production of cement and provides a clean technology option for sustainable development. This paper undertakes a review of the performance behaviour of reinforced geopolymer concrete structural elements and summarises the findings on the mechanical performance of reinforced GPC elements, e.g., columns, beams, and walls. In this review study, the mechanical properties of GPC structural elements have been investigated and compared with that of OPC concrete. The failure mode of GPC structural element has also been reported, and it was almost in the same manner of OPC concrete failure. The potential of GPC with regards to the chemical resistance and heat resistance could be significantly employed in the various industrial constructions such as marine constructions, pavements, and sewage pipes, etc. Moreover, it was observed that GPC could be safely used in structural elements owing to its excellent mechanical properties using provisions of design codes. More experimental studies are required to give a better understanding of the mechanical properties of GPC for its mass utilization in diversified application areas and spread the clean technology option in the construction industry.

Behaviour and design of air-cured GFRP-reinforced geopolymer concrete square columns

Conventional steel-reinforced ordinary Portland cement concrete is prone to corrosion. Geopolymer concrete is a new durable cementitious material, and the glass fibre-reinforced polymer (GFRP) is an attractive alternative to steel because of GFRP's compelling physical and mechanical properties, corrosion resistance and electromagnetic transparency. This study investigates the structural properties of 11 air-cured square geopolymer concrete columns reinforced with GFRP bars at various stirrup spacings of 50, 100 and 150 mm. The specimens were tested under varying loading conditions to generate interaction diagrams for comparison with theoretical predictions from existing codes and standards. Effective confinement and higher ductility were achieved by reducing the stirrup spacing. High strains indicating buckling or rupture of the longitudinal GFRP bars and confinement of the core were measured. The comparison between the experimental data and design codes showed that the load-carrying capacity of the columns were favourably under-predicted from a design viewpoint when the compressive GFRP bars were excluded. The strength of the concentrically loaded columns was up to 39·6% higher than the code predictions. The GFRP-reinforced geopolymer concrete columns showed a 10·8% average increment in the load-carrying capacity over their plain concrete sections.

Modelling glass fibre-reinforced polymer reinforced geopolymer concrete columns

Glass fibre-reinforced polymer (GFRP) bar and stirrup reinforced geopolymer concrete (GPC) is increasingly recognised as a potential replacement to the conventional steel-reinforced ordinary Portland cement (OPC) concrete due to its superior durability. This paper proposed an analytical model to predict the load-displacement relationship of the concentrically and eccentrically loaded GFRP-GPC columns. The cross-section was divided into a number of strips and a strain gradient was assigned to determine the stresses in the cover, core and reinforcement. The theoretical predictions were then validated using experimental results from previous studies on the behaviour of GFRP-GPC, GFRP-OPC concrete and steel-GFRP concrete systems. It was found that the predicted peaks load, displacements at peak load and ductility indices were generally in close agreement with the experimental results of the GFRP-GPC columns. However, the model had a tendency to over-predict the stiffness of GFRP-OPC concrete and steel-OPC concrete columns in the elastic range. Overall, the proposed analytical model is suitable for GFRP-GPC systems and could facilitate the widespread use of this composite material.

Experimental Investigation of Rectangular Air-Cured Geopolymer Concrete Columns Reinforced with GFRP Bars and Stirrups

AbstractGlass fiber-reinforced polymer (GFRP) bars in construction are increasing in popularity due to their excellent corrosion resistance, high tensile strength to weight ratio, and low maintenan...

Rectangular Stress-block Parameters for Fly-ash and Slag Based Geopolymer Concrete

Although there has been a numerous quantity of studies investigating the mechanical properties of geopolymer concrete (GPC), parameters for designing GPC structures are still not systematically investigated and carefully justified. ACI rectangular stress-block parameters are able to predict well the strength of conventional concrete structures but their applicability for GPC is questionable. This study aims to establish new sets of rectangular stress-block parameters for GPC with a broad range of the compressive strength up to 66 MPa. The proposed rectangular stress-block parameters in this study are based on two analytical concrete stress-strain models and measured curves from previous studies of GPC materials. The results from this study show that the use of ACI recommendations for concrete structure in designing GPC beams is still acceptable with high accuracy. However, the axial load-carrying capacity of GPC columns computed by ACI parameters deviate significantly from the experimental results while the proposed parameters provide a good correlation with these experimental data. The significant difference is mainly due to the modification of k3, which is the ratio of concrete strength in real structures to standard cylinder samples. This study suggests that the assumption of k3 = 0.9 in previous studies for conventional Portland concrete is not suitable for use in deriving the stress-block parameters of GPC. In some cases, this ratio should be reduced to 0.7 depending on the curing condition.

Behavior of Ambient Cured Geopolymer Concrete Columns under Different Loads

Behavior of Ambient Cured Geopolymer Concrete Columns under Different Loads

Behaviour of Ambient Cured Steel Fibre Reinforced Geopolymer Concrete Columns Under Axial and Flexural Loads

This study investigates the behaviour of ambient cured geopolymer concrete column specimens reinforced with steel fibres under different loading conditions. Three types of steel fibres (straight micro steel fibre, deformed macro steel fibre and hybrid steel fibre) were used in reinforcing the geopolymer concrete column specimens. Also, geopolymer concrete column specimens without steel fibre were tested as reference column specimens. Sixteen circular geopolymer concrete column specimens of 150 mm diameter and 600 mm height were cast and tested. The influences of the addition of different types of steel fibres and the loading conditions (concentric axial load, eccentric axial load and four-point bending) on the performance of the geopolymer concrete column specimens were investigated. The test results showed that the peak axial load and bending moment of fibre reinforced geopolymer concrete column specimens were higher than those of the geopolymer concrete column specimens without steel fibres under different loading conditions. Also, the addition of different types of steel fibres resulted in significant improvements in the ductility of the geopolymer concrete column specimens. The addition of hybrid steel fibre showed the highest improvement in the peak axial load, bending moment and the ductility of ambient cured geopolymer concrete column specimens.

Experiments and Finite Element Analysis of GFRP Reinforced Geopolymer Concrete Rectangular Columns Subjected to Concentric and Eccentric Axial Loading

Despite a number of recent studies illustrating the effective use of Glass Fibre Reinforced Polymer (GFRP) rebars as longitudinal reinforcement for concrete compression members. There is a lack of sufficient experimental and numerical studies on their combined action response. This paper demonstrates the use of finite element analysis to predict the response of GFRP reinforced geopolymer and ordinary Portland cement concrete columns under concentric and eccentric axial load in light of experimental data used for validation. The commercial numerical analysis software ABAQUS was used to carry out a parametric study using different material models, element types and mesh sizes. The concrete was simulated using reduced integration 8-noded hexahedral elements, C3D8R. The elasto-plastic material behaviour and the post-peak degradation in strength and stiffness of the concrete were modelled using the widely used concrete damage plasticity model available in ABAQUS. As for the GFRP bars and stirrups, a linear elastic behaviour was considered. To validate the model, the measured load-deflection responses were compared with the predicted curves. It was found that the experimental curves were in close agreement with the predicted load–displacement responses. The predicted N-M strength interaction diagrams matched the measured curves from the experiment, particularly for GFRP RC columns with a large spacing between the ligatures because they exhibited ductile failure which was well captured by the numerical model.

Experimental study on fly ash and lead smelter slag-based geopolymer concrete columns

Geopolymer concretes have emerged as novel engineering materials with the potential to significantly reduce the environmental footprint of concrete manufacture and utilise high volume of industrial waste materials. Although significant experimental research has focused on the development of geopolymer mix design, there is far less information available regarding the performance of geopolymer concretes at a member level. This has implications in transferring geopolymer concretes from a laboratory material to a material in which can be specified in practice. This paper addresses the application of geopolymer concrete at a member level through an experimental investigation on the behaviour of fly ash/granulated lead smelter slag (GLSS)-based geopolymer concrete columns and beams tested under concentric and eccentric loading. Slenderness effect of the geopolymer concrete columns is investigated and axial load-moment interaction envelopes are generated experimentally. The analytical interaction diagrams are compared to those calculated using classical methods for normal reinforced concrete beams and columns. The results of the comparison show that the analytical interaction diagrams overestimated the test results due to variation in material properties. Nevertheless, the results reveal that fly ash/GLSS-based geopolymer concrete exhibits similar structural behaviour to ordinary Portland cement (OPC) concrete. The results also highlight potential issues with the scaling of ambient-cured geopolymer concrete to the structural level.

Axial compression behavior of reinforced geopolymer concrete columns with demolished concrete lumps

Abstract This paper presents results of an experimental study on the axial compression behavior of reinforced geopolymer concrete columns with demolished concrete lumps (DCLs). A total of 22 reinforced concrete short columns were tested under axial compression. The test variables include the type of fresh concrete (ordinary Portland cement concrete (CC) and geopolymer concrete (GC)), strength level of fresh concrete (FC) and demolished concrete, and replacement ratio of FC by DCLs. The test results were used to evaluate the effect of strength difference between fresh and demolished concrete, and replacement ratio of FC by DCLs on bearing capacity and deformation ductility of geopolymer concrete columns with DCLs. Data from these tests showed that the axial compression behaviors of short columns made of geopolymer concrete and ordinary concrete with DCLs were similar. The ultimate bearing capacity and stiffness of recycled concrete columns with DCLs decrease with an increase in replacement ratio. Nevertheless, the maximum reduction in bearing capacity of geopolymer recycled concrete columns is only 10%, when the replacement ratio of FC by DCLs is 24%. The strength difference between fresh concrete and DCLs has a significant influence on mechanical properties of recycled concrete columns, especially for geopolymer recycled concrete columns. Compared to ordinary recycled concrete columns with DCLs, geopolymer recycled concrete columns with DCLS exhibit a slight lower bearing capacity, but a higher ductility.