Flexural strength of concrete prism strengthened using CFRP with modified mortar

Reinforced concrete (RC) is a good durable material that commonly used in construction compared to others. However, reinforced concrete structures may be damaged and are suffering from various deteriorations because of overloading and an inadequacy of design which may be attributed to cracks, spalling, large deflection, and more. Hence, it is essential to find repair and strengthening techniques of deteriorated concrete structures not only suitable in terms of the economy, but also to use them for their intended service life

Nonlinear finite element analysis of reinforced concrete beams strengthened with textile fine grained mortar

Nowadays, there was an increasing need of repairing and upgrading the reinforced concrete (RC) structure due to the deterioration of the structure. The fibre reinforced polymer (FRP) was commonly used for structural retrofitting purposes. However, owing to the debonding of the FRP from the concrete substrate and high cost of epoxy, it was gradually replaced with textile fine grained mortar (TFGM) nowadays. The TFGM system has been widely used in the construction field nowadays to repair the structure. Our study focus on the strain performances of the concrete surface, steel reinforcement and the textile itself. There were many proven experimental results showing that the TFGM was more effective than the other strengthening method such as FRP plate method. The experimental work done by previous researcher on investigation of strain performances of the concrete surface, steel reinforcement and the textile itself which consists of eleven (11) RC beams with dimension 150 x 200 x 2500 mm. The RC beams were strengthened with FGM and TFGM with 4 layers. The investigation continued with the finite element (FE) strain performance analysis with using Advanced Tool for Engineering Nonlinear Analysis (ATENA) software. The strain of the concrete surface, steel reinforcement and the textile were measured at a mid-point of RC beam. Then, the results of the finite element analysis software ATENA compared against the experimental results. The strain performances of the concrete and steel reinforcement improved noticeably when the number of layers of textile reinforcement used increased

Flexural Behaviour of Reinforced Concrete Beams with Openings Strengthened by Textile Reinforced Concrete (TRC) Wrap

This paper presents an experimental study of reinforced concrete beams with circular and square openings at the flexure zone. Selected beams were strengthened using Textile Reinforced Concrete (TRC) wraps. A total of six beam specimens measuring 250 mm (height) x 200 m (width) x 1700 mm (length) were cast using high strength concrete with a compressive strength of 64 N/mm2. The beams tested consisted of a solid control beam, unstrengthened concrete beams with openings and strengthened concrete beams with openings. The effect of circular and square openings on the flexure zone of concrete beams was investigated. All the beams were simply supported and tested up to failure under four-point loading. From the test results, it was found that the presence of openings at the flexure zone significantly reduces the strength and stiffness of the beams. The use of TRC wrap around the beam openings increases the ultimate capacity and stiffness of the beams. In addition, it also reduces excessive vertical cracks and deflection in beams considerably compared to unstrengthened concrete beams with openings

Study on IBS Cooling Panel Wall System with Difference Types of Cooling Mediums

Global warming has caused worldwide average surface temperature to rise about 0.74oC during the past 100 years, which is partly aggravated by air-conditioning that releases chlorofluorocarbons (CFCs) and forming a vicious cycle.  This paper proposes a cooling house system that can promote thermal comfort in buildings without air-conditioning.  The cooling panel wall forms a part of an Integrated Building System (IBS), and is essentially made of tubes filled with either water or glycerin as the coolant.  Target strength for the panel wall was designed based on the Malaysian Standard (MS) while the building ventilation system followed the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) standard. The results are reported based on indoor and outdoor temperature difference together with relative humidity to identify the best performing house model and also coolant.  The outcome of this research is expected to add value to heritage house design concepts with a better promotion of air flow and circulation in the building, without over-usage of natural resources and higher building cost to achieve the same objective.&nbsp

Flexural behaviour of plain concrete prism strengthened by textile fine grained mortar

This paper presents a flexural strength study of concrete incorporated with textile fine grained mortar (TFGM) as a strengthening laminate. TFGM is a combination of fine grained mortar (FGM) with alkali resistant glass fabric (AR glass). Fine grained sand with 600 m maximum size was used in FGM and fly ash (FA) or rice husk ash (RHA) has been used as a partial substitute for ordinary Portland cement (OPC). The potential of TFGM as strengthening laminate was tested under monolithic load with three point flexure loading. The TFGM were laid in layers of two, four, six, and eight. Results shown a promising flexure enhancement of up to three times of unstrengthened concrete when eight layers of both RHA and FA were laid. Load bearing capacity and ductility of the samples increased about 200% and 61%, respectively, compared to control samples as well. The outcome shows a highly potential use of agro-waste as cement replacement to produce load bearing structural component

Shear Capacity of Reinforced Concrete Beam with an Opening Retrofit Using Steel Fiber and Metakaolin

This study presents the experimental work of reinforced concrete beam with opening at shear zone and added with steel fibre and metakaolin to increase the shear capacity of the beam. A total of five (5) beams were casted and tested under four-point bending test. One beam served as the control specimen, two beams were beams with one and two opening respectively while the other two beams were beams with added steel fibre and metakaolin. The type of steel fibre used was a hooked-end steel fibers with the dimensions of 0.9mm in diameter, 60mm in length, and 0.5% of steel fiber was added by volume of beam, and 5% of metakaolin by volume of beam were used. From the experimental results, it was found that the two beams with added steel fibre and metakaolin shows an increase in shear capacity compared with the beams with opening without the steel fibre and metakaolin. The highest shear force recorded was 79.11 kN (beams with added steel fibre and metakaolin) which shows an increase for about 54.3 % compared with the same beam with opening without added steel fibre and metakaolin

Strength, water absorption and thermal comfort of mortar bricks containing crushed ceramic waste

This present study investigated the crushed ceramic waste utilisation as sand replacement in solid mortar bricks. The percentage of crushed ceramic waste used were 0% (CW0), 10% (CW10), 20% (CW20) and 30% (CW30) from the total weight of sand. The dimension prescribed of mortar bricks are 215 mm x 102.5 mm x 65 mm as followed accordance to MS 2281:2010 and BS EN 771-1:2011+A1:2015. Four (4) tests were conducted on mortar bricks namely crushing strength, water absorption, compressive strength of masonry units and thermal comfort. The incorporation of ceramic waste in all designated mortar bricks showed the increment of crushing strength between 23% and 46% at 28 days of curing and decrement water absorption between 34% and 44% was recorded corresponding to control mortar bricks. The prism test of masonry units consists of mortar bricks containing ceramic waste indicated the high increment of compressive strength at about 200% as compared to mortar brick without ceramic waste. The thermal comfort test of ceramic mortar bricks were also showed the good insulation with low interior temperature. Therefore, the ceramic waste can be utilised as a material replacement to fine aggregate in mortar brick productions due to significant outcomes performed

Fresh Properties and Compressive Strength of 3D Printing Concrete Containing GGBS as Partial Cement Replacement

3D printed concrete is a particular mix of concrete that has been specially prepared to flow easily through the printing nozzle. The foundations of 3D printed concrete constructions are stacked, with each layer put on top of a preceding layer of pumped concrete. Despite its potential, the construction industry has been confronted with several material issues. The cement replacement in the concrete has also been intensively studied, but in 3D printed concrete, this matter has not been seen clearly. It still cannot be seen whether the cement replacement produces a good result for the 3D printed concrete. This research investigated the fresh characteristics and compressive strength of 3D printed concrete using GGBS as a partial cement replacement in the mixture. In addition, the optimal proportion of GGBS as a partial cement replacement in 3D printed concrete is also evaluated. In this study, the fresh properties of 3D printing were examined by a flow table test, a buildability test, and an extrudability test, while compression strength was assessed for the mechanical properties. The percentage of GGBS used will vary from 20% to 50% with a 10% increment by weight of cement, and the water-cement ratio was fixed at 0.5. The cube specimen for the compression test was 50 mm x 50 mm x 50 mm and was cured for 7 and 28 days. The findings show that the flowability of this 3D printed concrete increased as the percentage of GGBS increased. All of the specimens also passed the buildability and extrudability tests. The compressive strength of this 3D printed also increased as the percentage increased, but it decreased back at 50% GGBS replacement. Overall, this experiment shows that 40% GGBS replacement is the optimum proportion as cement replacement in 3D printed concrete as it shows the highest compressive strength, which is 57.3 MPa

Modified Epoxy for Fibre Reinforced Polymer Strengthening of Concrete Structures

Fibre-Reinforced Polymer (FRP) is a preferable material for repairing concrete structure due to excellent material properties and effective installation cost over the long-term maintenance of structures. The successful application of FRP strengthening system very much depends on the bond between the concrete substrate and the FRP material using epoxy adhesive. Epoxy acts as a bridge to transfer stress from the concrete to the FRP material. The use of wet lay-up technique to apply FRP onto concrete structure requires epoxy to undergo a curing process normally referred to as cold curing. This paper intends to give a review of the problems with cold-cured epoxy and its effect on structural performance. Cured epoxy is characterised as brittle; therefore, modifications of epoxy are required to toughen the epoxy to suit the purpose of repairing a concrete structure. The methodological approaches from previous studies on modified epoxy were collected and reviewed in this paper. This review also offers some important insights regarding the use of sustainable materials, as well as recommendations for new epoxy in the future. &nbsp

Thermal Conductivity Of Lightweight Concrete Block With Various Cooling Agent

Energy was the important sources to human life. Due to increases energy demand in daily life, the energy consumption was increase day by day because of the heat load from solar radiation and heat produced by people. Toward sustainable development, this research was carried out to develop a lightweight concrete (LWC) block with various cooling agent such as glycerine, propylene glycol, coconut shell and gypsum powder. Six lightweight concrete (LWC) block with the size 250mm (L) × 250mm (W) × 100mm (T) were tested for thermal conductivity value.  From the experimental result, it shows that lightweight concrete (LCW) block with various cooling agent obtained thermal conductivity value of 0.17W/mK - 0.36W/mK lower than thermal conductivity value for normal lightweight concrete (0.8W/mK) depending on concrete density.  The lightweight concrete (LCW) block with cooling agent having low thermal conductivity value will reduce energy consumption in building