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Articles 1 - 30 of 31
Full-Text Articles in Engineering
Effects Of Heat Treatment On Oil Palm Shell Coarse Aggregates For High Strength Lightweight Concrete, Hilmi Mahmud
Effects Of Heat Treatment On Oil Palm Shell Coarse Aggregates For High Strength Lightweight Concrete, Hilmi Mahmud
Hilmi Mahmud
In this study, the effects of heat treatment on oil palm shell (OPS) coarse aggregates are evaluated for high strength lightweight concrete (HSLWC). OPS coarse aggregates are subjected to heat treatment at two temperature settings (60 and 150. °C) and duration of heat treatment (0.5 and 1. h). The reduction in density is found to be within the range of HSLWC when heat-treated OPS aggregates are added into the oil palm shell concrete (OPSC). The results reveal that workability of the OPSC increases with an increase in temperature and duration of heat treatment of the OPS aggregates. It is found …
Effects Of Using Silica Fume And Polycarboxylate-Type Superplasticizer On Physical Properties Of Cementitious Grout Mixtures For Semiflexible Pavement Surfacing, Hilmi Mahmud
Hilmi Mahmud
Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of …
Effects Of Aggregate Gradation On The Physical Properties Of Semiflexible Pavement, Hilmi Mahmud
Effects Of Aggregate Gradation On The Physical Properties Of Semiflexible Pavement, Hilmi Mahmud
Hilmi Mahmud
Semiflexible pavement (SFP), a composite pavement, is formed by filling into a very open porous asphalt skeleton a specifically designed water consistency fluid mortar with a very high early and 28-day strength. The amalgamation of both components will produce a SFP where it will replace the conventional wearing course. The main goal of this investigation is to study the effect of various aggregate gradations towards producing SFP. These include determining the optimum binder, volumetric properties, and durability and strength of each aggregate gradation. The final results were statistically analyzed and two factor variance analyses (ANOVA) were performed to check on …
Engineering Properties Of Oil Palm Shell Lightweight Concrete Containing Fly Ash, Hilmi Mahmud
Engineering Properties Of Oil Palm Shell Lightweight Concrete Containing Fly Ash, Hilmi Mahmud
Hilmi Mahmud
The effect of cement replacement with type F fly ash at 0%, 10%, 30% and 50% on some engineering properties of an oil palm shell (OPS) high strength lightweight concrete was investigated. The properties studied include workability, density, compressive strength, splitting tensile strength, flexural strength, water absorption and drying shrinkage. The effect of initial water curing periods of 2, 4 and 6. days after demoulding and air drying environment on the 28-day compressive strength was also investigated. The test results showed that even with 50% substitution of cement with fly ash, a low cost grade 30 OPS lightweight concrete can …
Oil Palm Shell Lightweight Concrete Containing High Volume Ground Granulated Blast Furnace Slag, Hilmi Mahmud
Oil Palm Shell Lightweight Concrete Containing High Volume Ground Granulated Blast Furnace Slag, Hilmi Mahmud
Hilmi Mahmud
With the ever-increasing industrialization and urbanization, huge amounts of natural resources are required to make concrete. Green concrete can provide a solution to reducing the negative impact of the concrete industry. This paper presents the results of experiments conducted to produce green structural lightweight concrete by using oil palm shell (OPS) as coarse aggregate, and ground granulated blast furnace slag (GGBFS) as a supplementary cementing material at 30%, 50% and 70% replacement of cement, and exposed to different curing conditions. Depending on the curing condition, test results show the possibility of producing green structural lightweight aggregate concrete with 28-day compressive …
Effect Of Magnesium Sulphate On Self-Compacting Concrete Containing Supplementary Cementitious Materials, Hilmi Mahmud
Effect Of Magnesium Sulphate On Self-Compacting Concrete Containing Supplementary Cementitious Materials, Hilmi Mahmud
Hilmi Mahmud
The length change is negligible and can be attributed to the normal distension of concrete. On the other hand, concrete suffering from mass loss gives a good indicator about the durability of SCC. Permeability of concrete is an important factor in classifying its durability generally; concrete with low Permeability will afford better protection of the reinforcement within it than concrete with high Permeability. In this paper, the assessment of magnesium sulphate (MS) attack on concrete containing various ratios of the supplementary cementitious materials (SCM) was investigated for concrete containing FA, RHA, and GGBS with cement replacement levels of 15%, 10%, …
Relationships Between Compressive Strength Of Cement-Slag Mortars Under Air And Water Curing Regimes, Hilmi Mahmud
Relationships Between Compressive Strength Of Cement-Slag Mortars Under Air And Water Curing Regimes, Hilmi Mahmud
Hilmi Mahmud
In this investigation 12 mortar mixes including three groups were prepared using binder contents 380 and 500 kg/m 3. All the specimens were cured after casting and demoulding in curing regimes, i.e. at room temperature (ac) and in water (wc). The highest strength was obtained for cement-slag mortars 380-wc at later ages as 80 MPa. For all groups of mortars, there could rarely be strength loss at later ages. It was observed that in duration of 3-7 days, wc is the optimum for all groups of mortars with exception of cement mortar 500 and slag mortar 500. In duration of …
Effect Of Replacement Of Normal Weight Coarse Aggregate With Oil Palm Shell On Properties Of Concrete, Hilmi Mahmud
Effect Of Replacement Of Normal Weight Coarse Aggregate With Oil Palm Shell On Properties Of Concrete, Hilmi Mahmud
Hilmi Mahmud
Oil palm shell (OPS) is a waste from the agricultural sector and is available in large quantities in the tropical regions. This paper investigates the effect of the replacement of normal weight coarse aggregate by oil palm shells on the compressive strength, density, modulus of elasticity, workability and water absorption. The gradation of substitution was 0, 28, 55, 83 and 100 %. Two mixes based on high strength concrete (HSC) with binder (cement + silica fume) content of 550 and 600 kg/m 3 were used. The results show that the compressive strength, density and modulus of elasticity decrease and workability …
Oil Palm Shell Lightweight Concrete As A Ductile Material, Hilmi Mahmud
Oil Palm Shell Lightweight Concrete As A Ductile Material, Hilmi Mahmud
Hilmi Mahmud
Crushed large oil palm shell (OPS) was used as a coarse aggregate in four different concrete mixtures. The stress-strain behavior and modulus of elasticity of OPS concrete were investigated and compared to granite normal weight concrete (NWC) and expanded clay lightweight concrete (LWC). The stress-strain curve of the OPS concrete showed that this type of LWC, in contrast to many types of structural LWC, is a ductile material. The highest E value of about 18.4. GPa was achieved in this study, which is significantly higher than previous studies. It was found that the E value of crushed OPS LWC was …
Lightweight Aggregate Concrete Fiber Reinforcement - A Review, Hilmi Mahmud
Lightweight Aggregate Concrete Fiber Reinforcement - A Review, Hilmi Mahmud
Hilmi Mahmud
The higher brittleness and lower mechanical properties of lightweight aggregate concrete (LWAC) compared to normal weight concrete (NWC) at the same compressive strength has prevented it from being widely used in the construction industry despite its many advantages. Studies have shown that the use of fibers in LWAC is an appropriate solution to resolve such problems. This paper reviews the influence of the addition of fibers on the properties of different types of LWAC. These properties include the workability, compressive strength, stress-strain behavior, tensile strength, modulus of elasticity, and compressive and flexural toughness. Generally, the inclusion of fibers in LWAC, …
A New Method Of Producing High Strength Oil Palm Shell Lightweight Concrete, Hilmi Mahmud
A New Method Of Producing High Strength Oil Palm Shell Lightweight Concrete, Hilmi Mahmud
Hilmi Mahmud
This paper presents a new method to produce high strength lightweight aggregate concrete (HSLWAC) using an agricultural solid waste, namely oil palm shell (OPS). This method is based on crushing large old OPS. Crushed OPS are hard and have a strong physical bond with hydrated cement paste. The 28 and 56. days compressive strength achieved in this study were about 53 and 56. MPa, respectively. Furthermore, it was observed that it was possible to produce grade 30 OPS concrete without the addition of any cementitious materials. Compared to previous studies, significantly lower cement content was used to produce this grade …
Effect Of Steel Fiber On The Mechanical Properties Of Oil Palm Shell Lightweight Concrete, Hilmi Mahmud
Effect Of Steel Fiber On The Mechanical Properties Of Oil Palm Shell Lightweight Concrete, Hilmi Mahmud
Hilmi Mahmud
This paper reports the results of a study conducted to investigate the effect of low volume content of steel fiber on the slump, density, compressive strength under different curing conditions, splitting tensile strength, flexural strength and modulus of elasticity of a grade 35 oil palm shell (OPS) lightweight concrete mixture. The results indicate that an increase in steel fiber decreased the workability and increased the density. All the mechanical properties except the modulus of elasticity (E) improved significantly. The 28. day compressive strength of steel fiber OPS lightweight concrete in continuously moist curing was in the range of 41-45. MPa. …
Shear Behaviour Of Reinforced Palm Kernel Shell Concrete Beams, Hilmi Mahmud
Shear Behaviour Of Reinforced Palm Kernel Shell Concrete Beams, Hilmi Mahmud
Hilmi Mahmud
The shear behaviour of palm kernel shell concrete (PKSC) beams prepared using palm kernel shell (PKS) as lightweight aggregate (LWA) is reported here. The shear strength of grade 30 PKSC with a density of 1850 kg/m(3) was found 24% higher than the corresponding normal weight concrete (NWC). Good aggregate interlock in PKSC was evident as it produced shorter jagged cracks compared to longer plain cracks of NWC. Further, PKSC was able to produce twice as many flexural and shear cracks compared to NWC. Tension stiffening between the tensile cracks of PKSC enhanced flexural rigidity and dowel action. The non-linear numerical …
Enhancement And Prediction Of Modulus Of Elasticity Of Palm Kernel Shell Concrete, Hilmi Mahmud
Enhancement And Prediction Of Modulus Of Elasticity Of Palm Kernel Shell Concrete, Hilmi Mahmud
Hilmi Mahmud
This paper presents results of an investigation conducted to enhance and predict the modulus of elasticity (MOE) of palm kernel shell concrete (PKSC). Scanning electron microscopic (SEM) analysis on palm kernel shell (PKS) was conducted. Further, the effect of varying sand and PKS contents and mineral admixtures (silica fume and fly ash) on compressive strength and MOE was investigated. The variables include water-to-binder (w/. b) and sand-to-cement (s/. c) ratios. Nine concrete mixes were prepared, and tests on static and dynamic moduli of elasticity and compressive strength were conducted. The SEM result showed presence of large number of micro-pores on …
Strength Properties Of Hybrid Nylon-Steel And Polypropylene-Steel Fibre-Reinforced High Strength Concrete At Low Volume Fraction, Hilmi Mahmud
Hilmi Mahmud
The strength properties of hybrid nylon-steel fibre-reinforced concrete were investigated in comparison to that of polypropylene-steel fibre-reinforced concrete, at the same volume fraction (0.5%). The content of the high performance macro structure steel fibres is at 0.4% volume fraction, and the content of micro nylon and polypropylene-fibres is at 0.1% volume fraction. The experimental results show that the compressive strength and splitting tensile strengths and modulus of rupture (MOR) properties of the nylon-steel fibre concrete improved by 3.2, 8.3 and 10.2%, respectively, over those of the polypropylene-steel fibre concrete. On the impact resistance, the first-crack and failure strengths, and the …
High-Strength Rice Husk Ash Concrete Incorporating Quarry Dust As A Partial Substitute For Sand, Hilmi Mahmud
High-Strength Rice Husk Ash Concrete Incorporating Quarry Dust As A Partial Substitute For Sand, Hilmi Mahmud
Hilmi Mahmud
Quarry dust is a by-product from the granite crushing process in quarrying activities. This paper presents the findings from experimental work undertaken to evaluate the suitability of quarry dust as a partial substitute for sand in high-strength concrete (HSC) containing rice husk ash (RHA). Two grades of HSC mixes, to achieve 60 MPa and 70 MPa at 28 days, were designed with and without the incorporation of RHA. Quarry dust was then used in the mixes containing RHA as a partial substitute for sand, in quantities ranging from 10% to 40%. The slump of the fresh concrete and the compressive …
Renovation Explicit Dynamic Procedures By Application Of Trujillo Algorithm, Hilmi Mahmud
Renovation Explicit Dynamic Procedures By Application Of Trujillo Algorithm, Hilmi Mahmud
Hilmi Mahmud
In this paper, a Trujillo algorithm method for the exact solution of nonlinear explicit dynamic problems is developed. This method associates numerical techniques and it is applied to determine the natural frequencies of structures. The numerical predictions of the natural frequency are compared to analytical and experimental results. There was no direct method available for solving such a problem efficiently in the case of explicit dynamic analysis. The Trujillo algorithm is an indirect method and the approach is based upon the principle of conservation of energy. It is believed that the proposed method provides a powerful engineering tool in the …
Mathematical Modeling For Analysis Cable Structures, Hilmi Mahmud
Mathematical Modeling For Analysis Cable Structures, Hilmi Mahmud
Hilmi Mahmud
The cable structures are long tension structures. The main aim of this paper is to provide a new efficient method in all aspects of analysis of tension structures. Tension structures belong to high-nonlinearity structures. The approach of the proposed method is based on the principle of conservation of energy. In this paper a theory for nonlinear dynamics response analysis of tension structure is based on the minimization of the total potential dynamic work developed. © 2011 Academic Journals.
Mix Design And Mechanical Properties Of Oil Palm Shell Lightweight Aggregate Concrete: A Review, Hilmi Mahmud
Mix Design And Mechanical Properties Of Oil Palm Shell Lightweight Aggregate Concrete: A Review, Hilmi Mahmud
Hilmi Mahmud
To build environmentally sustainable structures, especially in developing countries, the possibility of using some agricultural wastes and industrial by-products from different industries as construction materials will be highly desirable and has several practical and economic advantages. Oil palm shell (OPS) is a form of agricultural solid waste in the tropical regimes. Research over the last two decades shows that OPS can be used as a lightweight aggregate for producing structural lightweight aggregate concrete. The density of OPS concrete is around 20 - 25% lower than normal weight concrete. Generally, mechanical properties of OPS concrete are slightly lower than the other …
Study On Properties Of Rice Husk Ash And Its Use As Cement Replacement Material, Hilmi Mahmud
Study On Properties Of Rice Husk Ash And Its Use As Cement Replacement Material, Hilmi Mahmud
Hilmi Mahmud
This paper investigates the properties of rice husk ash (RHA) produced by using a ferro-cement furnace. The effect of grinding on the particle size and the surface area was first investigated, then the XRD analysis was conducted to verify the presence of amorphous silica in the ash. Furthermore, the effect of RHA average particle size and percentage on concrete workability, fresh density, superplasticizer (SP) content and the compressive strength were also investigated. Although grinding RHA would reduce its average particle size (APS), it was not the main factor controlling the surface area and it is thus resulted from RHA's multilayered, …
Production Of High Strength Concrete Incorporating An Agricultural Waste- Rice Husk Ash, Hilmi Mahmud
Production Of High Strength Concrete Incorporating An Agricultural Waste- Rice Husk Ash, Hilmi Mahmud
Hilmi Mahmud
Rice husk which is an agricultural waste, constitutes about one-fifth of the 500 million tonnes of rice produced annually worldwide. Normally, the residue is disposed off by burning at the mill sites and the resultant rice husk ash (RHA) is dumped on a waste land. This generates environmental, pollution and land dereliction problems. Under controlled burning and if sufficiently ground, the highly reactive ash that is produced can be used as a supplementary cementing material or in the production of high strength concrete (HSC). This paper shows that it is relatively easy to produce high strength Grade 80 concrete incorporating …
An Innovative Concrete Practice Performance Measurement Towards Environmental Improvement In Malaysia, Hilmi Mahmud
An Innovative Concrete Practice Performance Measurement Towards Environmental Improvement In Malaysia, Hilmi Mahmud
Hilmi Mahmud
The environmental impact from the concrete construction industry is quite alarming. The industry is embarking into improving the concrete performance and exploring into alternative materials to reduce such impact. An area which is lacking is improvement in the quality of concrete practice itself. By having good concrete practice, a good quality concrete can be achieved. This paper proposed a performance measurement of concrete practice and applies the measurement to assess the quality of concrete practice for a concrete structure project in Malaysia. © 2010 IEEE.
Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Hilmi Mahmud
Effect Of Aggregate Size And Proportion On Strength Properties Of Palm Kernel Shell Concrete, Hilmi Mahmud
Hilmi Mahmud
This paper presents information on the physical and mechanical properties of different sizes of palm kernel shells (PKS) used here as lightweight aggregates (LWA) and their influence on mechanical properties of palm kernel shell concrete (PKSC). Silica fume and fly ash were used as cementitious materials and all mixes had 1% superplasticizer on cement weight. It has been found that PKS consists of about 65 to 70% of medium size particles in the range of 5 to 10 mm. The other two sizes, namely, small (0-5 mm) and large (10-15 mm) sizes were found to influence the mechanical properties of …
Development Of Lightweight Concrete Using Industrial Waste Material, Palm Kernel Shell As Lightweight Aggregate And Its Properties, Hilmi Mahmud
Hilmi Mahmud
Agricultural industrial wastes produced after extracting palm oil from palm fruits known as palm kernel shell (PKS) are available in large quantities in Indonesia, Malaysia, Nigeria and other tropical countries. Malaysia is the second largest palm oil producing country in the world. This paper reports the results of an investigation conducted to utilize the PKS as lightweight aggregate to produce grade30 concrete with density of about 1850kg/m 3. The properties of both PKS and crushed granite aggregates were compared. The concrete produced using PKS referred to here after as palm kernel shell concrete (PKSC) and its properties were compared with …
Comparison Of Mechanical And Bond Properties Of Oil Palm Kernel Shell Concrete With Normal Weight Concrete, Hilmi Mahmud
Comparison Of Mechanical And Bond Properties Of Oil Palm Kernel Shell Concrete With Normal Weight Concrete, Hilmi Mahmud
Hilmi Mahmud
The comparison of the fresh, mechanical and bond properties of grade 30 lightweight concrete, namely oil palm kernel shell concrete (OPKSC) with normal weight concrete (NWC) of similar strength is presented in this paper. Oil palm kernel shell (OPKS), an industrial waste has been used as lightweight aggregates (LWA) in the OPKSC. In addition, mineral admixtures, 10% of silica fume and 5% fly ash have been used. The OPKSC produced a density reduction of about 20% compared to NWC. The addition of silica fume enhanced the compressive strength and thus OPKSC produced 28-day compressive strength up to 37 MPa. The …
Shear Strength Of Oil Palm Shell Foamed Concrete Beams, Hilmi Mahmud
Shear Strength Of Oil Palm Shell Foamed Concrete Beams, Hilmi Mahmud
Hilmi Mahmud
Four reinforced oil palm shell foamed concrete (OPSFC) beams were fabricated, and their shear behaviour was tested. The OPSFC has a target density of approximately 1600 kg/m3 and a 28-day compressive strength of about 20 MPa. Two beams were cast with shear reinforcements while the other two were cast without such reinforcements. For comparison, four reinforced normal weight concrete (NWC) beams were also cast. The beams that contained shear links failed in flexure mode, while those without links failed in shear mode. The experimental results indicated that the shear capacities of OPSFC beams without shear links are higher than those …
Material Aspects For High-Strength High Performance Concrete, Hilmi Mahmud
Material Aspects For High-Strength High Performance Concrete, Hilmi Mahmud
Hilmi Mahmud
The merits of high-strength high performance concrete (HSHPC) depend on the quality of constituent materials. The constituent materials play the vital roles to improve the performance of HSHPC. In particular, the use of supplementary cementing materials is essential when high strength and durability become the most critical issues to be considered for concretes. The addition of high-range water reducer and air-entraining admixtures are also inevitable to achieve good workability and freeze-thaw durability, respectively. This paper discusses various aspects of the major component materials of HSHPC. It briefly describes the property requirements of the component materials and emphasizes their contents or …
Ductility Behaviour Of Reinforced Palm Kernel Shell Concrete Beams, Hilmi Mahmud
Ductility Behaviour Of Reinforced Palm Kernel Shell Concrete Beams, Hilmi Mahmud
Hilmi Mahmud
This paper presents the results on the structural behavior of palm kernel shell concrete and its comparison with normal weight concrete (NWC). The structural grade palm kernel shell concrete, a lightweight concrete (LWC) produced using palm kernel shell (PKS) an agricultural waste and by-product of the production of palm oil as lightweight aggregate, referred to hereafter as PKSC. The concrete is of grade 30 and the reinforced concrete beams of size 150 mm x 250 mm x 2100 mm were prepared to study the structural behavior. Similar grade concrete using NWC were also prepared and reinforced. The flexural behavior of …
Chemical Stabilization Of Scrap Metal Yard Contaminated Soil Using Ordinary Portland Cement: Strength And Leachability Aspects, Hilmi Mahmud
Chemical Stabilization Of Scrap Metal Yard Contaminated Soil Using Ordinary Portland Cement: Strength And Leachability Aspects, Hilmi Mahmud
Hilmi Mahmud
In this study, the strength development and lechability aspects of metal-contaminated soil treated with ordinary portland cement (OPC) were investigated. The soil was collected from a scrap metal yard within the outskirts of Kuala Lumpur, Malaysia. Metal composition analysis indicated that the predominant metals present in the soil were iron (42,194 mg/kg), aluminium (8874 mg/kg), zinc (690 mg/kg), lead (428 mg/kg), copper (107 mg/kg) and chromium (52 mg/kg). The contaminated soil was treated with OPC using cement-to-dry soil (C/Sd) ratios of 0.5, 1 and 2. The effectiveness of the treatment was evaluated by performing unconfined compressive strength (UCS) as well …
Stabilization/Solidification Of Lead-Contaminated Soil Using Cement And Rice Husk Ash, Hilmi Mahmud
Stabilization/Solidification Of Lead-Contaminated Soil Using Cement And Rice Husk Ash, Hilmi Mahmud
Hilmi Mahmud
This paper presents the findings of a study on solidification/stabilization (S/S) of lead-contaminated soil using ordinary Portland cement (OPC) and rice husk ash (RHA). The effects of varying lead concentrations (in the form of nitrates) in soil samples on the physical properties of their stabilized forms, namely unconfined compressive strength (UCS), setting times of early mixtures and changes in crystalline phases as well as chemical properties such as leachability of lead, pH and alkalinity of leachates are studied. Results have indicated that usage of OPC with RHA as an overall binder system for S/S of lead-contaminated soils is more favorable …