Noorwirdawati Ali

Physical and Chemical Properties of Coal Bottom Ash (CBA) from Tanjung Bin Power Plant

The objective of this study is to determine the physical and chemical characteristics of Coal Bottom Ash (CBA) obtained from Tanjung Bin Power Plant Station and compare them with the characteristics of natural river sand (as a replacement of fine aggregates). Bottom ash is the by-product of coal combustion during the electricity generating process. However, excess bottom ash production due to the high production of electricity in Malaysia has caused several environmental problems. Therefore, several tests have been conducted in order to determine the physical and chemical properties of bottom ash such as specific gravity, density, particle size distribution, Scanning Electron Microscopic (SEM) and X- Ray Fluorescence (XRF) in the attempt to produce sustainable material from waste. The results indicated that the natural fine aggregate and coal bottom ash have very different physical and chemical properties. Bottom ash was classified as Class C ash. The porous structure, angular and rough texture of bottom ash affected its specific gravity and particle density. From the tests, it was found that bottom ash is recommended to be used in concrete as a replacement for fine aggregates.

Ultimate strength capacity of a square hollow section filled with fibrous foamed concrete

Concrete-filled sections used as building columns have become popular due to their architectural and structural elements. In recent years, there has been a renewed call for the improvement of materials used as concrete to fill the composite columns. Among these materials, foamed concrete has received great attention due to its structural characteristics and its potential as a construction material used in hollow sections. However, its behaviors as infill material in a hollow section, such as its strength and failure mode, should be investigated. In this study, experimental research was conducted to compare the experimental and theoretical values of its ultimate strength capacity. Eight specimens of hollow steel sections with two different thicknesses were filled with fibrous foamed concrete and then subjected to compression load. The obtained results were compared with those obtained from a hollow section with the same thicknesses, but were filled with normal foamed concrete. Results show that the ultimate strength capacity of the experimental value is the same as that of the theoretical value based on Eurocode 4. The largest percentage values between theoretical and experimental results for thicknesses of 2 and 4 mm are 58% and 55%, respectively.

Contribution of Polypropylene Fibre in Improving Strength of Foamed Concrete

Foamed concrete as favorable substitution conventional concrete can be used in wide range of constructions. Usage the Polypropylene Fibre (denoted as PF) in this investigation examined contribution of PF on strength of foamed concrete. Mechanical test were performed to measure effect of PF on improving compressive and splitting tensile strength. Results indicate that PF significantly improving compressive and splitting tensile strength. Behavior of PF where drawn into foamed concrete similarly with normal concrete. The fibrillation and interfacial bonding between PF and matrix has been occurred and reduced the micro crack of matrix and prevented propagation crack growth. However influence of porous of foamed concrete is considered. Process of curing continuation 60 and 90 days indicate that interfacial adhesion is wider when cement hydration process is running. Scanning Electron Microscope (SEM) exhibits condition microstructure of foamed concrete added by PF alter the microstructure, especially interfacial bonding between PF and matrix.

Development of Green Concrete from Agricultural and Construction Waste

As the demand for affordable and quality houses increases in the 11th Malaysia Plan, issues regarding environmentally sustainable construction gain more prominence as specified by the Construction Industry Transformation Plan, CITP 2016–2020. The emphasis on green construction has been stressed by the introduction of the strategic plan, and, hence, the need for a construction system which is eco-friendly, reduces carbon emission and uses less earth natural resources is required. Thus, this paper studies the past and present research on green concrete utilizing agricultural waste and construction waste. Agricultural waste such as palm oil fuel ash (POFA) and rice husk ash (RHA) together with recycled concrete aggregate (RCA) from construction waste will be used as part replacement of cement and aggregate, respectively, whilst palm oil fibre (POF), which is another form of agricultural waste, will be added as binders for the concrete matrix. Literature has shown that by replacing ordinary Portland cement with POFA and RHA enhances the compressive strength and tensile strength of concrete by up to 20% and 10%, respectively. Similar trends were observed when POF were added to concrete where improvements in its strength and crack properties were observed. Replacing natural aggregates with RCA also has similar impact to the compressive strength of concrete, but a lower flexural strength was recorded.

Shear strengthening and shear repair of 2-Span continuous RC beams with CFRP strips

AbstractAn experimental investigation on initially strengthened and repaired 2-span continuous RC beams with carbon fiber–reinforced polymer (CFRP) strips was conducted. Fourteen full-scale beam sp...

Compressive strength and initial water absorption rate for cement brick containing high-density polyethylene (HDPE) as a substitutional material for sand

The rapid growth of today’s construction sector requires high amount of building materials. Bricks, known to have solid properties and easy to handle, which leads to the variety of materials added or replaced in its mixture. In this study, high density polyethylene (HDPE) was selected as the substitute materials in the making of bricks. The reason behind the use of HDPE is because of its recyclable properties and the recycling process that do not emit hazardous gases to the atmosphere. Other than that, the use of HDPE will help reducing the source of pollution by avoiding the millions of accumulated plastic waste in the disposal sites. Furthermore, the material has high endurance level and is weatherproof. This study was carried out on experimenting the substitute materials in the mixture of cement bricks, a component of building materials which is normally manufactured using the mixture of cement, sand and water, following a certain ratios, and left dried to produce blocks of bricks. A series of three different percentages of HDPE were used, which were 2.5%, 3.0% and 3.5%. Tests were done on the bricks, to study its compressive strength and the initial water absorption rate. Both tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the use of 2.5% of HDPE shown values of 12.6 N/mm2 while the use of 3.0% of HDPE shown values of 12.5 N/mm2. Onto the next percentage, 3.5% of HDPE shown values of 12.5 N/mm2.

Compressive and tensile strength for concrete containing coal bottom ash

The increasing demand in the construction industry will lead to the depletion of materials used in construction sites such as sand. Due to this situation, coal bottom ash (CBA) was selected as a replacement for sand. CBA is a by-product of coal combustion from power plants. CBA has particles which are angular, irregular and porous with a rough surface texture. CBA also has the appearance and particle size distribution similar to river sand. Therefore, these properties of CBA make it attractive to be used as fine aggregate replacement in concrete. The objectives of this study were to determine the properties of CBA concrete and to evaluate the optimum percentage of CBA to be used in concrete as fine aggregate replacement. The CBA was collected at Tanjung Bin power plant. The mechanical experiment (compressive and tensile strength test) was conducted on CBA concrete. Before starting the mechanical experiment, cubic and cylindrical specimens with dimensions measuring 100 × 100 × 100 mm and 150 × 300 mm were produced based on the percentage of coal bottom ash in this study which is 0% as the control specimen. Meanwhile 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of CBA were used to replace the fine aggregates. The CBA concrete samples were cured for 7 days and 28 days respectively to maintain the rate of hydration and moisture. After the experimental work was done, it can be concluded that the optimum percentage of CBA as fine aggregate is 60% for a curing period of both 7 days and 28 days with the total compressive strength of 36.4 Mpa and 46.2 Mpa respectively. However, the optimum percentage for tensile strength is at 70% CBA for a curing period of both 7 days and 28 days with a tensile strength of 3.03 MPa and 3.63 MPa respectively.

Crack classification in concrete beams using AE parameters

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm x 250 mm x 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

Sound absorption coefficient of coal bottom ash concrete for railway application

A porous concrete able to reduce the sound wave that pass through it. When a sound waves strike a material, a portion of the sound energy was reflected back and another portion of the sound energy was absorbed by the material while the rest was transmitted. The larger portion of the sound wave being absorbed, the lower the noise level able to be lowered. This study is to investigate the sound absorption coefficient of coal bottom ash (CBA) concrete compared to the sound absorption coefficient of normal concrete by carried out the impedance tube test. Hence, this paper presents the result of the impedance tube test of the CBA concrete and normal concrete.

Rehabilitation of Continuous Reinforced Concrete Beams in Shear by External Bonding of Carbon Fiber Reinforced Polymer Strips for Sustainable Construction

To achieve sustainability in construction, the rehabilitation of existing concrete structures is vital in ensuring its structural integrity and longevity. Therefore, an experimental investigation on the shear strengthening of 2-span continuous reinforced concrete (RC) beams wrapped with carbon fiber reinforced polymer (CFRP) strips were conducted. The beam specimens were subjected to four point bending test and loaded incrementally until failure occurs. Different wrapping schemes and layers of CFRP strips were externally bonded within the shear span of the beams. The failure load, modes of failure, its crack patterns, deflection profile were recorded and presented for discussion. From observation, the experimental results indicated good improvement as the shear strengthened beams shows enhanced failure load and shear strength capacity. An improved stiffness and ductility behaviour was also observed compared to the control beam. Comparison with ACI 440 (2008) design provisions for shear strength shows that the prediction values underestimated its experimental results. This indicates that the enhanced shear performances of the 2-span continuous RC beams prove the reliability of CFRP as a strengthening material. Hence, the shear strengthening technique allows the rehabilitation process of existing structural members to improve its structural integrity, longevity and sustainability.