Izwan Johari

Influence of Rice Husk Ash on the Engineering Properties of Fired-Clay Brick

The aim of this study is to determine the influence of rice husk ash (RHA) on the engineering properties of fired-clay brick with the present of 10% sand. Temperature 1200°C is selected as the optimum temperature based on the preliminaries study. X-ray Diffraction (XRD) and X-Ray Fluorescence (XRF), were carried out to determine the characteristic of raw materials used. Mechanical properties of rice husk ash-clay bricks are determined in terms of compressive strength, porosity and water absorption. The results shows that increase in RHA replacement percentage reduce the compressive strength and linear shrinkage of fired-clay bricks while the porosity and water absorption value increase. From the investigation, we can conclude that the optimum mixing ratio for fired-clay brick containing RHA is 15% because it complied with the minimum requirement for building material in term of strength and water absorption.

Effect of Curing Time and Sintering to the Properties of Geopolymer Mortars

In this study, the geopolymer mortars were synthesized with fly ash (FA) and silica powder as aluminosilicate sources and a combination of sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution and distilled water as alkaline activator. Commercial sago was used as a pore former in the mortars. The percentage of sago used were 10, 20 and 30 wt% of FA. The amount of added water used in each mixture was 5% by weight of FA, NaOH solution and Na2SiO3 solution. The formed geopolymer mortars were cured for 1, 3 and 7 days and sintered at 1000 °C. X-ray fluoresence (XRF) shown that FA contains higher amount of silica (SiO2) and alumina (Al2O3) which is important as aluminosilicate sources. The properties of the geopolymer mortars before and after sintered at 1000 °C have been investigated. The results show that geopolymer mortars with 10% of sago content with curing time of 7 days and sintered at 1000 °C give the highest compressive strength of 13.5 MPa.

Microstructure and Mechanical Properties of Cement Mortar Incorporate with Coated Expanded Polystyrene Beads

Abstract. Coated Expanded polystyrene (CEPS) mortar is a new lightweight building material that demonstrate a good mechanical properties by improving it interfacial bonding properties. By using the field emission scanning electron microscope (FESEM) with high resolution imaging, the mortar morphology at different ages (7, 14 and 28 days) can be observed. The results shows that coated EPS bead provide a good bonding as there is no gap in the interfacial surface at 28 days.

Physicomechanical enhancement on Portland composite concrete using silica fume as replacement material

The addition of supplementary cementitious materials may change the physical and mechanical properties of concrete. Mineral additions which are also known as mineral admixtures have been used with cement for many years. However, this research did not use Ordinary Portland Cement (OPC) but using the Portland Cement Composite (PCC). The aim of this study is to determine the effect of partial substitution of PCC by silica fume (SF) on the physicomechanical properties especially the compressive strength of the hardened PCC–SF composite concrete. Silica fume was used to replace PCC at dosage levels of 5%, 10%, 15% and 20% by weight of cement in concrete. The results show that on 7 days the PCC concrete exhibited lower early age strength but PCC-SF concrete improved and gain strength up to grade 30 in 7 days. The utilisation of SF resulted in significant improvement of Portland composite concrete admixture.

Quantification of Concrete Waste Generated in Housing Construction Sites via Site Sampling: Development of a Multiple Linear Regression Model

Waste generated in construction sites has recently increased and has become an uncontrollable cause of environmental problems and profit loss to contractors. The lack of real data or research on such wastes is due to the lack of suitable policies regarding this issue. The actions of contractors are not controlled by rules on this issue. This situation leads to the lack of action or awareness on the side of the contractor. Concrete waste is also part of the waste generated in construction sites. We determine the concrete waste generated in construction stages and conduct multiple linear regression analysis of the amount of column waste generated. The methodology employed in this study involves site observations, interviews with site personnel, and sampling at housing construction sites. The estimation method is utilized for the sampling of concrete waste. Results show that the average percentage of column waste is 13.93% and that of slab waste is 0.34%. These percentage values are derived from the total order of the concrete. The difference is due to the sizes of structures and method of handling. The regression model obtained from the sample data on column waste resulted in an adjusted R2 value of 0.895. Therefore, the model predicts approximately 89.5% of the factors involved in concrete waste generation.

Physical Performance of Fired Clay Brick Containing Two Types of Rice Husk Ash

The effect of using two types of replacement materials i.e., controlled burning rice husk ash (CBRHA) and uncontrolled burning rice husk ash (UCBRHA) on the physical performance of fired clay brick was studied. The compressive strength, porosity, and density were determined. The results revealed that the silica content for UCBRHA was higher than CBRHA. On the other hand, the highest compressive strength achieved was 93.45 N/mm2 for fired clay brick containing 20% CBRHA. It was a 4.2% of increment from 0% to 20%. Higher replacement levels contribute to the increase of porosity and decrease in density.