Afizah Ayob

UHPFRC as Repair Material for Fire-Damaged Reinforced Concrete Structure – A Review

Exposure of concrete to intense heat will cause deterioration of its strength and durability. Previously, the fire-damaged concrete was repaired using the shotcrete and normal concrete. Recent studies utilize fibre reinforced polymer (FRP) in repairing fire-damaged concrete. Ultra High Performance Fiber Reinforced Concrete (UHPFRC) mostly developed using fine size aggregate, cement, silica fume, super plasticizer and reinforced with steel fibre has an excellent mechanical properties compared to high strength concrete and with an addition of steel fibre in the UHPFRC enhances its ductility behaviour which is not possessed by normal concrete, hence, UHPFRC indicates a promising candidate as repair material to fire-damaged concrete. The aim of this paper is to review on the properties of UHPFRC to be utilized as repair material to fire-damaged concrete structure based on previous research on UHPFRC and fire-damaged structure.

Water treatment sludge as an alternative liner for landfill site: FTIR and XRD analysis

This study investigated the chemical composition of water treatment sludge (WTS) as material for protection layer in landfill. The potential reuse of WTS as protection layer or landfill liner is a long-term approach to sludge disposal in terms of economic and environmental sustainability. The chemical properties of WTS as an alternative landfill liner was compared with conventional landfill liner which is clay soil (CS). The CS and WTS in this study were obtained from the paddy field, Permatang Pauh and Bukit Toh Allang Water Treatment Plant (WTP), Pulau Pinang. The chemical compositions of the CS and WTS were analyzed using FTIR and XRD. Experimental results of FTIR showed that the WTS has an almost 70% similarity in terms of chemical composition with CS. Analysis using XRD showed that kaolinite, (Al2SO4H(OH)4) is the main mineral in both CS and WTS samples. Thus, WTS has potential to be used and commercialized as a landfill liner as it could be one of the option or alternative to CS. In addition the slu...

Analysis of Soil Nailing under Earthquake Loading in Malaysia Using Finite Element Method

Soil nailing has become a widely accepted method and offers a practical solution towards construction of permanent retaining wall, slope stabilization and protection of existing cuts from failure. In Malaysia, soil nailing is typically performed on cut slope and installed with grouting as preventatives method due to erosion problem. However, although the effectiveness of soil nailing system may be well understood by practitioners, the slope failure and collapses of deep excavation are continuously occurs, especially for the construction in the earthquake zone. Malaysia has numerous experiences of earthquake even this country has been categorized as low seismicity group. Hence, it is become important in the scope of geotechnical engineering to analyze and study the effect of earthquake to soil nailing systems in Malaysia. Aims of this paper are to focus and study this technical issue using the application of finite element program. This research study selects PGA of 0.08g based on the location of major population in Malaysia. Safety factor was calculated in this finite element program using phi-c reduction. Soil nailing relatively give satisfactory response under seismic, so pseudo-static method is applied for seismic loading study. Based on the static analysis results, the FOS for the deep excavation stabilized with soil nailing is 1.54. However, by considering the earthquake or seismic loading, the FOS reduces to 1.16 and the percentage of reduction is about 25%. Total displacement was observed slightly difference in soil nailing analysis during an earthquake and static analysis

Carbon footprint hotspots of prefabricated sandwich panels for hostel construction in Perlis

Sustainable design and construction have gained increasing research interest, and reduction of carbon from building construction has become the main focus of environmental strategies in Malaysia. This study uses life cycle assessment and life cycle inventory analysis frameworks to estimate the amount of carbon footprint expressed in carbon dioxide equivalent tons (CO2e) produced by manufacturing prefabricated Industrialized Building System sandwich panels and its installation for a five-story hostel in Perlis, Malaysia. Results show that the carbon footprint hotspots were centered on boiler machine operation and cement with 4.52 and 369.04 tons CO2e, respectively. This finding is due to the extensive energy used for steam heating and high engine rating for the boiler. However, for cement, the carbon footprint hotspots are caused by the large quantity of cement applied in shotcrete mixture and its high extraction and production CO2 emission values. The overall onsite materials generated 96.36% of the total...

Mechanical properties and chemical reaction of 3-aminopropyltriethoxysilane of polypropylene, recycle acrylonitrile butadiene rubber and sugarcane bagasse composites

The mechanical and chemical properties of sugarcane bagasse (SCB) treated with 3-aminopropyltriethoxysilane (3-APS) filled polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr) bio-composites were aim and investigated. The composites with different SCB loading from 5 wt.% to 30 wt.% were prepared using heated two-roll mill by melt mixing at temperature of 180°C. Tensile properties of composites which is tensile strength, Young Modulus and elongation at break were investigated. Increasing of treated SCB filler loading in composites have increased the Young modulus, however, decreased the tensile strength and elongation at break of the composites. The chemical properties and morphology of composites were investigated using Fourier transform infra-red analysis. These findings were supported by micrograph diagram from the morphological study. SCB filler treated with 3-APS has improved the adhesion and gave strong interfacial bonding between SCB filler and PP/NBRr matrices which results in good tensile strength of composites.

Applications of waste material in the pervious concrete pavement: A review

Pervious concrete pavement is one of the innovative structures designed in order to manage the quantity and quality of urban stormwater for a sustainable development. In general, pervious concrete pavement enables water to permeate through its structure and have a capability to cater dynamic loads at the same time. However, the conventional pervious concrete pavement lacks a superior strength while performing as pavement structure. Thus, an extensive research has been carried out in order to explore the possible materials to be incorporated into the pervious concrete pavement for better physical, structural and mechanical properties. The objectives of this paper are to review the waste materials used in the pervious concrete pavement along with their mechanical, durability and permeability performance.

A review of nanoclay applications in the pervious concrete pavement

In recent years, the use of nanoclay has received various interests in order to enhance the properties of construction materials which can also be eligible for pavement technology and engineering application. This review paper summarizes the effect of nanoclay as cement replacement and additive to the performance of pervious concrete pavement. The addition of nanoclay to pervious concrete has demonstrated improvements in strength properties such as compressive and flexural strength, durability such as freeze-thaw and chloride penetration resistance, shrinkage, and denser microstructure but at the same time reduced the porosity, permeability and water absorption properties. This enhancement is due to the roles of nanoclay as nanoreinforcements, nanofillers, nucleation site, and reactive pozzolans in order to promote hydration and improve material properties.

Analysis of Raft Foundation with EPS Geofoam for Earthquake Resistant

It is becoming a great challenge for civil engineers to design a foundation which able to minimize the effect of an earthquake. A major earthquake produces a strong ground motion in the subsoil and surface structures supported on the soil mass will be induced to move and absorb the dynamic forces. Seismic retrofit of existing foundations is an alternative. However, the modification of this existing foundation toward earthquake resistances raises issues which are far from being totally resolved. Innovative material such as EPS is widely accepted in structural engineering due to its characteristic to absorb the dynamic force effectively. This EPS material demonstrated the practicality and has been applied for geotechnical engineering for various reasons. Based on this, a research which is related to the application of EPS in mitigating the earthquake forces, particularly for raft foundations was conducted properly in this research. The various types and thickness of EPS located beneath the raft foundation and over the soft soil are studied. A finite element program is utilized to develop the computer simulation models. Based on the results, Expended Polystyrene (EPS) Geofoam, placed beneath the raft foundation is able to produces the minimum settlements when subjected to earthquake loading rather than raft foundation modeled without EPS and increasing the density of EPS will simultaneously decrease the settlement of a foundation.

Calculation of Axial Loads on Columns by Tributary Area Method and Finite Element Method

Basic concept of structural design is to transmit the loading from superstructure to substructure. This idea normally required sound knowledge of structural design and rational engineering judgments. Recently, there have several techniques that can be utilized to determine the superstructure loading, such as finite element method and tributary area method. However, the compatibility of both methods in order to determine the loading from superstructure is prime important and has been investigated in this research framework. Axial loading, represented as products from dead load and service load, which are imposed on the top of slab is directly transmit to the column nearby and modelled through computer simulation. Models of slab were then varies and studies through comparison with broad dimensions of slab thickness, ranging in 100 mm to 600 mm. Results has shown the increasing of slab thickness will indirectly increases the rigidity characteristic of slab and potential to distribute the axial load equally for all column members. Axial load against slab thickness on corner, edge, center, outer and inner column demonstrated the incompatibility for both methods, finite element method and tributary area method in determining the axial loading from superstructure.