Siew Choo Chin

Effect of Poly(Ethylene-co-Vinyl Acetate) as a Self-Healing Agent in Geopolymer Exposed to Various Curing Temperatures

The elevated temperature curing could cause rapid evaporation of moisture from geopolymer framework, which in turn will trigger a drying shrinkage to the specimen and affect the performance of hardened geopolymer. Different studies have been done on the characteristics of fly ash based geopolymer, yet scarce studies are available on the addition of self-healing agent to reduce shrinkage phenomenon during heat curing. This study experimentally examines the effect of PVA (poly ethylene vinyl acetate) as a self-healing agent on the mechanical properties of geopolymer mortar after 24 hours curing in various temperatures. The effect of PVA was evaluated at 1% of fly ash weight in geopolymer mixture with various curing temperatures of 70, 80, and 90 oC. The curing process of geopolymer mortar was done for 24 hours without any post-cast detainment period. Compressive strength and porosity tests were conducted to provide fundamental information on the hardened properties of geopolymer mortar. Based on the results, 90oC heat curing showed higher improvement on compressive strength properties than other specimens. Strength development of geopolymer mortar was also affected by various geopolymerization rate that relies on the heat exposure.

Potential Use of Bamboo Reinforced Concrete Beams towards Sustainable Construction

Bamboo is a natural resource that has the potential to be a substitute of steel reinforcement in reinforced concrete. This paper presents a study on the mechanical properties of bamboo as well as the behaviour of bamboo-reinforced concrete beams. Six bamboo samples were tested for compressive strength and tensile tests, respectively. In terms of structural properties, three reinforced concrete beams were tested to failure under four-point bending, which includes a control beam, a fully and partially reinforced beams with bamboo. Results of mechanical properties showed that bamboo with nodes has higher capability to be able to resist compressive loading compared to bamboo without node. On the other hand, tensile results revealed that bamboo splint managed to achieve 12.5% of the stress of high yield steel with comparable strain value. Results of structural properties showed that beam reinforced with bamboo can achieve approximately 46% of the beam capacity of the steel reinforced beam. Bamboo reinforced concrete beams failed in a brittle manner under bending with vertical cracks in the tension zone.

Behavior of Extended End-Plate Steel Beam to Column Connections

Background: The main objective of this study is to simulate the behaviour of steel beam-to-column connections using the computer package of finite element analysis (FEA) known as “ABAQUS”. Objective: This paper presents the investigations of extended end-plate connections (EP). A one-model segment is examined under the impact of concentrated load and the exclusive boundary conditions were tested. The analysis of the nonlinear behaviour of the connection is a complicated science and needs to use programs to solve this problem. Experimental works are normally conducted for this type of studies which used more of money, time and effort. Therefore, with the availability of simulation applications, these problems can be addressed. Results and Conclusion: The results of the evaluation were compared with the experimental data from the available literature. In this case, nonlinearity materials were used. A sample study on EP connections was carried out using both material and geometric nonlinearities. The comparison of FEA results with corresponding experimental results confirms the correlation and convergence between them.

The Potential of Blended Cement Mortar Brick Using Sewage Sludge and Eggshell Waste

Sewage sludge is one of the largest contributors toward solid waste in Malaysia. The amount of sewage generated is expected to increase every year, which is in line with the population growth in Malaysia. Landfilling has been identified to be the most widely used method to dispose of sewage sludge in Malaysia. This high amount of solid waste resulted in shortage of landfilling area, which has indirectly increased the cost of waste management in Malaysia. Hence, the aim of this chapter is to identify the potential use of solid wastes; namely sewage sludge and eggshell as partial cement replacement in mortar bricks. The sewage sludge and eggshell wastes were obtained from Indah Water Konsortium (IWK) and Eggtech Manufacturing, respectively. Both sewage sludge and eggshell powder were treated prior to mixing. The organic materials in the sewage sludge were removed through incineration process at a temperature of 800 °C for 3 h in which Incinerated Sewage Sludge Ash (ISSA) was produced. Meanwhile, the eggshell waste was dried under the sun before being ground into powder form. The treated ISSA and eggshell powder were then mixed with Ordinary Portland Cement, fine aggregates, and water to produce mortar bricks. Tests including compressive strength, flexural strength, and water absorption were conducted on bricks formed from four different percentages of eggshell powder (5–20%) with 10% ISSA. Findings showed that 10% ISSA as partial cement replacement with 5% eggshell as additive has increased the strength of the mortar bricks tested to 72% higher than the strength of the control bricks.

Durability Analysis of Natural Lime Concrete

Concrete is known to be durable and dependable material since it is resistance to weathering action and chemical attacks while maintaining its engineering properties. However, carbon dioxide produced by the cement industries had caused severe environmental pollution. To minimize carbon dioxide emission into the atmosphere, eggshell wastes are treated as partial cement replacement in this study. The eggshell was oven-dried at 105.5 °C for 24 h before grinding it into powder passing through sieve size 45 µm. Eggshell powder was used as partial cement replacement at 5, 10, 15 and 20%. The performance of the concrete mix was evaluated against control concrete mix. The specimens were tested on acid attack and sulphate attack. The concrete specimens were prepared in the form of cubes and then subjected to water curing for 28 days before immersed in sulphuric acid solution for 1800 h and sodium sulphate for 50 weeks respectively. From the analysis, it is observed that reduction of compressive strength of the concrete cubes for the acid attack and sulphate attack reduce gradually when the eggshell powder increase.

Potential External Strengthening of Reinforced Concrete Beam Using Natural Fiber Composite Plate

A study has been conducted to investigate the potential use of mengkuang leaves or Pandanus atrocarpus bonded with epoxy resin as external strengthening material for the strengthening of reinforced concrete (RC) beams. Physical and mechanical properties as well as structural properties of the mengkuang leaves-epoxy composite plates (MLECP) were evaluated in this study. Chemical treatment was performed on the dried mengkuang leaves using sodium hydroxide (NaOH) with concentrations of 2%, 5% and 8%. Scanning electron microscope (SEM) and flexural strength tests were conducted on the mengkuang leaves and flexural specimens, respectively. All the beams were tested to failure under four-point loading. Results showed that the flexural strength of the composite with 0.3 fiber volume ratio exhibited the highest flexural strength. Strengthening of RC beam using MLECP managed to increase the beam capacity.

A comparative study on different burning method of sewage sludge ash in mortar brick with eggshell powder as additive

Population growth that increasing every year has led to the increasing number of waste generated annually. Sewage sludge and eggshell waste production that also increasing every year is the major concerns in this research. The high content of heavy metals in sewage sludge was recorded harmful to environment if it is not dumped in proper way at the landfill area. In general, Cd, Pb and Zn represent the biggest concentrations of heavy metals in sewage sludge which can be source of pollution. Furthermore, the excessive disposal of eggshells to landfills may attract rats and worms due to the organic protein matrix that may pose health problem to the public. The demand on cement mortar brick nowadays has increased due to the good development of construction industries. This will lead to the increase of cement production. However, cement plant is one of the major contributors of carbon dioxide emission in the world. Hence, this research is helping in reducing the production of cement in helping to greener environment where sewage sludge will act as cement replacement material as the element contains in Sewage Sludge Ash (SSA) present the same elements as cement. The major components of SSA are SiO2, CaO, Al2O3, Fe2O3, Na2O, K2O, MgO and FeO. It is necessary to burn the sewage sludge to remove the heavy metal before it can be applied as cement replacement materials in mortar brick production. In this research, two different method of burning the sewage sludge producing Sewage Sludge Ash (SSA) will be tested. Methods used in this research to burn the sewage sludge are incineration method produced Incinerated Sewage Sludge Ash (ISSA) and also microwave method, produced Microwaved Sewage Sludge Ash (MSSA). Eggshell powder act as additive in this research due to its high content of calcium carbonate and has nearly same composition of limestone used in the production of cement. Different percentages of Eggshell Powder (ESP) (0%, 5%, 10%, 15%) and 10% fixed of MSSA and ISSA as optimum dosage partially replacing the cement used to test the brick mortar properties in term of compressive strength, flexural strength and also water absorption. Result shows that ISSA with 10% replacement of ESP is the most optimum brick with highest compressive strength and flexural strength compared to MSSA brick. While, MSSA brick with 10% of ESP shown the best result in water absorption. But, the water absorption rate for 10% ESP in ISSA still good as low in its range.