Fibre Reinforced Geopolymer Concrete Research Articles

Strength and Durability Characteristics of Steel Fibre Reinforced Geopolymer Concrete

Owing to the upturn inrepair and rehabilitation of structures that undergoes deterioration even before its intended life span; it has become necessary to study the durability properties of the structures. This paper deals with an experimental approach on the strength and durability characteristics of Geopolymer Concrete and Steel Fibre Reinforced Geopolymer Concrete with varying proportions of Fly ash, Waste Glass powder and GGBS (Ground Granulated Blast furnace Slag) as base material cured at room temperature. Sodium hydroxide (14M) and Sodium silicate are used as alkali activators. Steel fibres of length 60mm, 0.75mm diameter are used in two different proportions (0.25% and 0.50%). The results are compared with that of the Portland cement based plain and fibre reinforced control concrete. The durability characteristic involved in this study is Sorptivity test. The results reveal that Steel fibre reinforced Geopolymer concrete procures surpassing characteristics than that of Geopolymer concrete which in turn possess superior characteristics than that of conventional concrete.

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.

Current Challenges in Average Residual Strength Evaluation of K-Silicate-Based Fiber-Reinforced Geopolymer Concrete

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Experimental Investigation on the Effect of Corrosion on the Bond Between Reinforcing Steel Bars and Fibre Reinforced Geopolymer Concrete

This paper investigates the effect of corrosion on the bond between reinforcing steel bars and fibre reinforced geopolymer concrete. An accelerated corrosion method was used to corrode the reinforcing steel bars embedded in geopolymer concrete. Three types of steel fibres including straight micro steel fibre, deformed macro steel fibre, and hybrid steel fibre were used in this study. A total of ten geopolymer concrete mixes were used to evaluate the effect of corrosion of steel bar on the bond between steel bar and fibre reinforced geopolymer concrete. The pull-out test specimens were composed of concrete cubes with a side length of 160mm and reinforced with a deformed steel bar of 16 mm diameter located at the centre of the specimens. The test results showed that the addition of steel fibres in geopolymer concrete (fibre reinforced geopolymer concrete) significantly enhanced the bond strength of reinforcing steel bar. The bond strength of reinforcing steel bars embedded in steel fibre reinforced geopolymer concrete specimens reduced due to corrosion of reinforcement. However, the reduction of bond strength in steel fibre reinforced geopolymer concrete specimens was less than the reduction of bond strength in plain geopolymer concrete specimen.

A novel corrosion resistant repair technique for existing reinforced concrete (RC) elements using polyvinyl alcohol fibre reinforced geopolymer concrete (PVAFRGC)

Strain hardening fibre reinforced geopolymer concrete, which utilises waste material rather than primary mineral products and is suitable for cast-in-place applications, shows considerable potential as a resistant, more environmentally friendly, concrete repair material. This study assesses the corrosion protection performance of polyvinyl alcohol fibre reinforced geopolymer concrete as a repair material. The applicability of polyvinyl alcohol fibre reinforced geopolymer concrete as a repair material for preventing steel corrosion was investigated using specimens that simulated surface coating repair. Large scale beam repair was conducted using beams where part of the concrete cover at various depths (12.5% and 25% of the total beam depth) was replaced by polyvinyl alcohol fibre reinforced geopolymer concrete. Accelerated corrosion tests were performed using an induced current technique by applying a nominal 300 mA/cm2 constant anodic current for approximately 90 days. Results from flexural strength tests showed significant improvements in the structural performance of the reinforced concrete beams repaired with polyvinyl alcohol fibre reinforced geopolymer concrete following accelerated corrosion. The results can be summarised as follows: surface coating with polyvinyl alcohol fibre reinforced geopolymer concrete significantly reduced corrosion damage in terms of mass loss, crack distributions and structural performance, while differences in surface coating thickness also considerably affected the corrosion resistance of the repaired beams.

Fracture Behaviour of Fibre Reinforced Geopolymer Concrete

Geopolymers have several applications and concrete is one of the materials that can be produced with geopolymer as binder. Since industrial byproducts/wastes such as fly ash, iron slag, micronized biomass silica, silica fume, red mud, etc. can be used as a binder instead of Portland cement, geopolymer concrete (GPC) has generated lot of interest among the scientific and engineering community. This has also resulted in reduced carbon footprint of concrete and an effective method of disposing industrial waste. In this study GPC with a blend of class-f fly ash and ground granulated blast furnace slag as binder has been developed, and its flexural and fracture characteristics have been studied. The GPC developed has a 28-day compressive strength in the range 40-50 MPa. Incorporation of steel fibres resulted in increased flexural strength, enhanced fracture properties and ductility. The residual strength of steel fibre reinforced GPC was also determined in the study.

Experimental Investigation on Properties of Basalt Fiber Reinforced Geopolymer Concrete

Experimental Investigation on Properties of Basalt Fiber Reinforced Geopolymer Concrete

Low carbon building: Experimental insight on the use of fly ash and glass fibre for making geopolymer concrete

Abstract Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the construction field. In the current study, attempt was made to determine the strength characteristics of glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass fibres were added to the geopolymer concrete in varying proportions of 0.1–0.5% (in steps of 0.1%) by weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for all mixes. British standard concrete test specimens were cast for measuring compressive strength, split-tensile strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 °C for 24 h and natural environment, respectively. From the results, thermally cured concrete samples had better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of 24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split tensile strength increased by 5–10% in glass fibre-reinforced geopolymer concrete, containing 0.1–0.5% glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa).

Steel fibre reinforced geopolymer concrete (SFRGC) with improved microstructure and enhanced fibre-matrix interfacial properties

Geopolymers are aluminosilicate materials formed by mixing by-product materials with alkaline solutions, and which have several desirable properties compared to Portland cement concrete in terms of strength and durability. Most of the previous research on steel fibre reinforced geopolymer concrete (SFRGC) has focused on the properties of single or binary mixes hardened under heat curing conditions, which is a severe limitation for on-site, cast-in-place applications. In the current study, a novel plain and steel fibre reinforced geopolymer concrete (SFRGC), containing various types of commercial Silica Fume (SF) (densified, undensified and slurry silica fume) and varying Ground Granulated Blast Furnace Slag (GGBS) content in a ternary binder mixture, cured under ambient (room) temperature has been examined. An extensive experimental investigation was conducted to evaluate the fresh properties, mechanical characteristics and microstructure of the examined material. The experimental results indicate that the mechanical characteristics of all the examined mixes are enhanced by increasing the GGBS content, in both plain and steel fibre reinforced geopolymer concrete. Geopolymer concrete with undensified silica fume showed better mechanical strength compared to that with densified and slurry SF, due to the agglomeration and ineffective dispersion of the latter fume types. SEM microstructural observations and porosity measurements were also conducted. The results indicate that the inclusion of silica fume and increasing GGBS content leads to higher pozzolanic activity and pore infilling, providing relatively homogeneous, compact and dense microstructures and subsequently improved mechanical properties.

Crack Growth Resistance in Fibre Reinforced Geopolymer Concrete Exposed to Sustained Extreme Temperatures

Portland cement concrete (PCC) is now second only to potable water in per capita consumption. And notwithstanding its numerous benefits, Portland cement itself is responsible for between 4 to 5% of the world’s manmade greenhouse gas emissions. In this context, geopolymer concrete is a promising alternative, wherein the Portland cement binder is replaced entirely by supplementary cementitious materials triggered by alkaline activators. Relatively little is known on the fracture response of this system, especially when exposed to extreme temperatures. The study reported here focused on the crack growth response of such a system prepared with Class F fly ash and reinforced with steel and polymeric fibres up to 1% volume fraction. The geopolymerization was effected with a blend of sodium hydroxide and sodium silicate to achieve a compressive strength of 30 MPa at 28 days. The resulting geopolymer concrete was subjected to temperatures between-30 oC to 300 oC, sustained for 2 hours. A fibre blend of steel to polypropylene in the mass ratio of 4:1 was incorporated. Based on the results, four different stages for fracture behaviour were identified with superior fibre efficiency seen at sub-zero temperatures.

An Experimental Study on Flexural Behaviour of Fiber Reinforced Geopolymer Concrete Slabs

An Experimental Study on Flexural Behaviour of Fiber Reinforced Geopolymer Concrete Slabs

An Experimental Study of Fibre Reinforced Geo Polymer Concrete using Fly ash, GGBS and Polypropylene Fibres with a Partial Replacement of Normal Sand by Quarry Dust

An Experimental Study of Fibre Reinforced Geo Polymer Concrete using Fly ash, GGBS and Polypropylene Fibres with a Partial Replacement of Normal Sand by Quarry Dust

Engineering properties and fracture behaviour of high volume palm oil fuel ash based fibre reinforced geopolymer concrete

This article reports investigation carried out using high volume palm oil fuel ash (POFA-90%) based geopolymer concrete using oil palm shell (OPS) as coarse aggregate. The tensile and fracture properties of OPS based lightweight geopolymer concrete (OPSGC) with the addition of steel fibres (SF) of two aspect ratios (AR80, AR65) and three volume fractions (0.25%, 0.50%, 0.75%) were investigated. The results were compared with that of normal weight geopolymer concrete (NWGC) with and without steel fibre of AR80 and AR65 (0.50% volume fraction). The higher values of flexural and splitting tensile strengths of OPSGC could be attributed to stronger bond between the rougher surfaces of the crushed OPS and matrix. The addition of SF(AR80) produced higher splitting strength, flexural strength and total fracture energy of 5%, 6% and 50–80%, respectively compared to the corresponding values of SF(AR65). The toughness and equivalent flexural strength ratio of OPSGC were found higher than the corresponding values of NWGC and this could be attributed to the ductility of OPS. The values of residual load and residual strength in two-deflection limits of L/600 and L/150 indicated the progressive failure, which reflected the ductility of the OPSGC with fibres.

Durability characteristics of steel fibre reinforced geopolymer concrete

Escalation in the cost of repair and rehabilitation of concrete structures which develop distress much earlier than the design service life has turned the focus on the durability aspect of concrete. This paper presents the result of an experimental study conducted to evaluate the durability characteristics of plain and fibre reinforced geopolymer concrete and its comparison with Portland cement based conventional concrete. The durability parameters considered in this study include water absorption, abrasion resistance, resistance to chemical attack, effect of alternate wetting and drying and resistance against chloride ions. Test results revealed that plain and fibre reinforced geopolymer concrete possesses superior durability characteristics than conventional concrete of the same grade with respect to most of the durability parameters.

Bond behaviour of reinforcing bars embedded in steel fibre reinforced geopolymer concrete

An experimental investigation was carried out to study the influence of steel fibres on the bond strength of geopolymer concrete (GPC). Pull-out tests under monotonic loading were carried out. A total of 30 concentrically reinforced concrete cubes were cast and tested. Of these, six were made of GPC and the remainder were made from steel fibre reinforced geopolymer concrete (SFRGPC). High yield strength deformed bars of 10 mm, 12 mm and 16 mm diameter were used as reinforcement, the grade of concrete was M40 and different volume fractions (0·25% (16·62 kg/m3), 0·50% (39·25 kg/m3), 0·75% (58·87 kg/m3) and 1% (78·50 kg/m3)) of crimped steel fibres were used. The test results indicate that the addition of steel fibres to GPC significantly enhances the bond strength.

Fibre-reinforced geopolymer concrete with ambient curing for in situ applications

Geopolymer concrete is proven to have excellent engineering properties with a reduced carbon footprint. It not only reduces the greenhouse gas emissions (compared to Portland cement-based concrete) but also utilises a large amount of industrial waste materials such as fly ash and slag. Due to these positive attributes, it is becoming an increasingly popular construction material. Previous studies on geopolymer concrete report that heat curing plays an important role in gaining higher compressive strength values (as opposed to ambient curing), and hence the application of this material could be limited to precast members. Therefore, this research was aimed at investigating the effect of heat curing by comparing the mechanical properties such as compressive strength and ductility of ambient cured and heat cured geopolymer concrete samples. It is worth noting that there was marginal strength change due to heat curing. In Australia, fibre-reinforced geopolymer concrete is being used in precast panels in underground constructions. Commercially available geopolymer cement and synthetic fibres are effectively being used to produce elements that are more durable than what is currently used in industry. As a result, this research investigated the effects of polypropylene fibres in geopolymer concrete using 0.05 and 0.15 % fibres (by weight). The addition of polypropylene fibres enhances the compressive strength and the ductility of geopolymer concrete.

COMPARISON OF GLASS FIBER REINFORCED CONCRETE & GEOPOLYMER CONCRETE WITH GLASS FIBER REINFORCEMENT

In the world most commonly used as well as durable material is concrete. In the field of concrete tech nology, glass fiber reinforced concrete (GFRC) is the recently introduc ed material. GFRC has many advantages such as light weight material, steel reinforcement corrosion free and structural deterio ration free. So, these are the reason the researche rs all over the globe are attempting to develop high performance concrete wit h the use of glass fibers as well as admixtures. Wh ile the combination of fly ash, alkaline liquids, fine and coarse aggregate an d glass fibers resulted in the product called as Gl ass Fiber Reinforced Geopolymer Concrete (GFRGC). This product has many advantages such as high early strength, corrosion asulphate resistance and low shrinkage. The present work has compared the compressive strength, split tensile st rength and flexural strength for GFRC and GFRGC. From this comparison it is observed that except for the flexural strength the normal concrete with the addition of glass fibers shown good result s as compared to the geopolymer concrete with the a ddition of glass fibers. This work is only an accumulation of information about G FRC and the research work which is already carried out by other researchers.

Engineering properties of steel fibre reinforced geopolymer concrete

Engineering properties such as compressive strength, splitting tensile strength, modulus of rupture, modulus of elasticity and Poisson's ratio of geopolymer concrete (GPC) and steel fibre reinforced geopolymer concrete (SFRGPC) have been obtained from standard tests and compared. A total of 15 specimens were tested for determining each property. The grade of concrete used was M 40. The percentages of steel fibres considered include 0.25%, 0.5%, 0.75% and 1%. In general, the addition of fibres improved the mechanical properties of both GPC and SFRGPC. However the increase was found to be nominal in the case of compressive strength (8.51%), significant in the case of splitting tensile strength (61.63%), modulus of rupture (24%), modulus of elasticity (64.92%) and Poisson's ratio (50%) at 1% volume fraction of fibres. An attempt was made to obtain the relation between the various engineering properties with the percentage of fibres added.

Strain sensing of carbon fiber reinforced geopolymer concrete

Health monitoring of concrete structures is performed by assessing the structure’s state of stress. One such method involves monitoring electrical resistance variations as an indirect measure of stress variations. Carbon fibers were added to fresh geopolymer mix to enhance its electrical conductivity. AC-impedance spectroscopy analyses were performed on sample specimens to obtain their electrical resistance. Geopolymer concrete specimens entrained with carbon fibers were dynamically loaded in bending and uniaxial compression to observe changes in electrical resistance with respect to variations in their stress state. For beam specimens electrical resistance was found to follow a descending trend with increasing bending stresses. A more complex relationship was noted for cylinder specimens that were loaded axially. Overall experimental results suggest that conductive geopolymer could serve as a smart material in health monitoring applications of concrete structures.