Mohd Haziman Wan Ibrahim

Strength and permeability properties of concrete containing rice husk ash with different grinding time

The compressive concrete strength and the gas permeability properties over varying fineness of the rice husk ash were experimentally investigated. The relationships among them were analyzed. In this study eight samples made from the rice husk ashes with a different grain size were used, i.e. coarse original rice husk ash 17.96 μm (RHA0), 10.93 μm (RHA1) 9.74 μm (RHA2), 9.52 μm (RHA3), 9.34 μm (RHA4), 8.70 μm (RHA5), 6.85 μm (RHA6) and 6.65 μm (RHA7). The ordinary Portland cement was partially replaced with the rice husk ash (15 wt%). The test results showed that the RHA3 produced the concrete with good strength and low porosity. Additionally the strength of the concrete was improved due to the partial replacement of RHA3 material in comparison with normal coarse rice husk ash RHA0. On the other hand the influence of OPC and RHA materials on the concrete permeability was affected by the grinding time and age (i.e., curing time). The permeability coefficient decreased with the increasing of curing time. The relationships between compressive strength and permeability coefficient are greatly affected by curing times and are sensitive to the grinding cementitious systems.

The Effect of Bottom Ash on Fresh Characteristic, Compressive Strength and Water Absorption of Self-Compacting Concrete

Bottom ash is a solid residue produced through combustion process in a coal-fired power plant. It has been catogarized as a waste and usually disposed in the utility disposed site. With higher demand on the power energy, more coal-power plant are constructed and abundance of bottom ash are produced. Recently, the utilization of bottom ash in the construction industry has gained the interest of researches. Since it has similiar particle size distribution as normal sand, many attempt has been made in studying it potential use in mortar and concrete. In complementary to that, this paper presents the effect of bottom ash on fresh and hardened properties of self-compacting concrete (SCC). Bottom ash is used as fine aggregate replacing sand with replacement ratio range from 0% to 30% by volume. The effects of bottom ash on the SCC were investigated by comparing the test result of SCC mixed bottom ash with control specimens (0% of bottom ash). The test result on fresh properties of the concrete mixture revealed that, as the replacement level of bottom ash increased, the slump flow, L-box passing ratio and segregation resistance ratio (SR) decreased. Nevertheless, the slump flow time (T500) result increased with the increased of bottom ash content. The results show that the porosity and the irregular shape of the bottom ash particle has great influence on workability and viscosity of the fresh concete. The compressive strength and water absorption test are carried out on the sample at curing time of 7 and 28days. In terms of strength, the use of bottom ash in the production of SCC has increased the compressive strength of the concrete up to 15% replacement level. The increase in strength show the presence of the pozzolanic reactivity in a concrete with bottom ash particle. The water absorption rate was observed to be lower with a sample which having 10% and 15% replacement level.

Compressive and flexural strength of foamed concrete containing polyolefin fibers

Foam concrete is a lightweight concrete which is produced relatively inexpensively. However, due to its low strength and brittleness the application in building construction is rather limited. A study has been undertaken to investigate the effects of polyolefin fibers at a relatively low volume fraction (0 %, 0.2 %, 0.4 % and 0.6 %) on the compressive and flexural properties of foamed concrete. The foamed concrete was designed to achieve a target strength of 8-10 MPa with a density of 1600 kg/m3 at the age of 28 days. For each mixture, nine 100x100x100 mm cubes and three 100x100x500 mm beam were prepared. The compressive test was performed on cubes and three points loading flexural test on the beams was carried out in accordance to MS 26:Part 2:1991. Test results showed that polyolefin fibers only slightly improved the compressive strength and flexural strength of foamed concrete by 4.3% and 9.3% respectively.

Effect of Powder Loading and Binder Materials on Mechanical Properties in Iron-ABS Injection Molding Process

This paper presents the development of a new polymer matrix composite (PMC) feedstock material by the injection molding machine. The material consists of iron powder filled in an acrylonitrile butadiene styrene (ABS) and surfactant powder (binder) material. In this study, the effect of powder loading and binder content on the mechanical properties was investigated experimentally. The detailed formulations of compounding ratio by Brabender Mixer and injection molding machine of the sample specimen was used with various combinations of the new PMC material. Based on the result obtained, it was found that, higher powder loading of iron filler affected the hardness, tensile and flexural strength of PMC material. With 32% iron powder loading in ABS composites increase the flexural force, maximum stress and force of PMC material through an injection molding process.

ENGINEERING PROPERTIES OF NORMAL CONCRETE GRADE 40 CONTAINING RICE HUSK ASH AT DIFFERENT GRINDING TIME

ENGINEERING PROPERTIES OF NORMAL CONCRETE GRADE 40 CONTAINING RICE HUSK ASH AT DIFFERENT GRINDING TIME The effect of rice husk ash with different grinding time on the engineering properties of concrete was studied. Eight rice husk ashes with different grinding were used in this investigation. Rice husk ash was used to partially replace Portland cement Type I at 15% by weight of cementitious material. The 100-mm concrete cube specimens were cast and cured in water for 7 and 28 days. The compressive strength of concrete was designed to achieve of grade 40 N/mm2 at 28 days. A superplasticizer was added to all mixes to provide workability in the range of 110 - 120 mm. However, the water to cement ratio (w/c) of the concrete was maintained at 0.49. Based on the results, the morphology of the rice husk ashes were changed by grinding. These appear to be an optimum grinding time of approximate 90 minutes which the compressive strength increased significantly. Generally, incorporation of RHA at varies grinding time can be decrease or increased the engineering properties of concrete extremely.

Mechanical properties and thermal behaviour of two-stage concrete containing palm oil fuel ash

Two-stage concrete (TSC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Over the decades, the application of supplementary cementing materials in conventional concrete has become widespread, and this trend is expected to continue in TSC as well. Palm oil fuel ash (POFA) is one of the ashes which has been recognized as a good pozzolanic material. This paper presents the experimental results on the performance behaviour of POFA in developing physical and mechanical properties of two-stage concrete. Four concrete mixes namely, TSC with 100% OPC as a control, and TSC with 10, 20 and 30% POFA were cast, and the temperature growth due to heat of hydration and heat transfer in the mixes was recorded. It has been found that POFA significantly reduced the temperature rise in two-stage aggregate concrete and delayed the transfer of heat to the mass of concrete. The compressive and tensile strengths, however, increased with the replacement of up to 20% POFA. The results obtained and the observation made in this study suggest that the substitution of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great importance.

The Strength Behavior of Self-Compacting Concrete Incorporating Bottom Ash as Partial Replacement to Fine Aggregate

Self-compacting concrete which commonly abbrevited as SCC is a special concrete that have the ability to consilodate fully under its own self-weight without any internal or external vibration. This paper presents the experimental investigation carried out to study the strength of self-compacting concrete incorporating bottom ash at different replacement level of natural sand. The composite cement was used and the replacement level of bottom ash to natural sand is set up to 30% by volume. The strength properties such as compressive strength, split tensile strength and flexural strength of the concrete at the age of 7 and 28 days of curing day were conducted. Results shows that the strength of the concrete with bottom ash increased up to replacement level 15% higher than control specimens. This show that bottom ash can be used as supplimentary cementitious materials, having the pozzolanic reactivty.

Effect of Rice Husk Ash Fineness on the Properties of Concrete

In the present research, the effect of rice husk ash fineness on the properties of concrete was studied. Eight different fineness grades of rice husk ash were examined. A rice husk ash dosage of 15% by weight of binder was used throughout the experiments. The water-to-binder ratio was 0.49 to produce concrete having target strength of 40MPa at 28 d. Workability, compressive strength and gas permeability tests were carried out to identify the properties of concrete. The results revealed that increasing the fineness of RHA by mechanical grinding was found to improve the workability of RHA blended cement concrete. In addition, the use of RHA3 with mean particle size of 9.52μm produces the concrete with good strength. Finally, significant improvement was observed in mixtures incorporating RHA in terms of permeability coefficient.

A Study on Melt Flow Index on Copper-ABS for Fused Deposition Modeling (FDM) Feedstock

This paper presents of Polymer Matrix Composite (PMC) as feedstock used in Fused Deposition Modelling (FDM) machine. This study discussed on the development of a new PMC material by the injection molding machine. The material consist of copper powder filled in an acrylonitrile butadiene styrene (ABS), binder and surfactant material. The effect of metal filled in ABS and binder content was investigated experimentally by the Melt Flow Index (MFI) machine. Based on the result obtained, an increment of copper filled in ABS by volume percentage (vol. %) effected on melt flow index results. With highly filled copper in PMC composites increase the melt flow index results. It was concluded that, the propensity of the melt flow allow an internal force in PMC material through the injection molding and FDM machine.

Dynamic Analysis of an Office Building due to Vibration from Road Construction Activities

Construction activities are widely known as one of the predominant sources of man-made vibrations that able to create nuisance towards any adjacent building, and this includes the road construction operations. Few studies conclude the construction-induced vibration may be harmful directly and indirectly towards the neighbouring building. This lead to the awareness of study the building vibration response of concrete masonry load bearing system and its vibrational performance towards the road construction activities. This study will simulate multi-storey office building of Sekolah Menengah Kebangsaan (SMK) Bandar Enstek at Negeri Sembilan by using finite element vibration analyses. The excitation of transient loads from ground borne vibrations which triggered by the road construction activities are modelled into the building. The vibration response was recorded during in-situ ambient vibration test by using Laser Doppler Vibrometer (LDV), which specifically performed on four different locations. The finite element simulation process was developed in the commercial FEA software ABAQUS. Then, the experimental data was processed and evaluated in MATLAB ModalV to assess the vibration criteria of the floor in building. As a result, the vibration level of floor in building is fall under VC-E curve which was under the maximum permissible level for office building (VC-ISO). The vibration level on floor is acceptable within the limit that have been referred.