Fadzil Mat Yahaya

Effect of flexural crack on plain concrete beam failure mechanism A numerical simulation

The flexural failure of plain concrete beam occurs along with development of flexural crack on beam. In this paper by using ABAQUS, mechanism failure of plain concrete beam under three steps have been simulated. The cracking moment has been analytically calculated and applied on the both sides of the fixed beam, and flexural crack has been simulated on beam. Displacement, von Mises, load reaction, displacementcrack length, von Mises-crack length and von Mises-displacement of beams have been graphical depicted. Results indicated that, the flexural crack governs beam mechanism failure and its effects on beam resistance failure. It has been found that the flexural crack in initial stage it developed slowly and changes to be fast at the final stage of collapsing beam due to reduction of the flexural resistance of beam. Increasing mechanical properties of concrete, collapse displacement is reduced.

Effect of Seashell Powder on Flexural and Compressive Strength of Cement Mortar in Early Age

The several structures have been failed due to low flexural and compressive strength of OPC paste. Many waste materials are applicable for modify flexural and compressive strength of cement mortar. Among the additives, a natural additive has been selected. The effect of seashell powder on flexural and compressive strength of cement mortar has been investigated. The result indicated that with replacement of 1% seashell, the deflection, time to failure and maximum load to failure of concrete beam has been improved. And the strain, time to failure and compressive modulus elasticity of cubic specimen has not considerably been changed. The more investigation on macro and micro property of OPC is necessary to obtain better results.

An Investigation on Effect of Oil Palm Shell Ash on Flexural Strength and Compressive Strength of Cement Mortar

One of waste agriculture materials is oil palm shell ash. It has been producing in high quantity in palm oil mill, and for storage of that an investment requires. In this paper, an attempt has been made to analysis effect of oil palm shell ash on compressive and flexural strength of cement mortar. The compressive strength and flexural strength of cement mortar has been measured. To improve accuracy of work 50% cement and 50% fine sand has been proposed in cement mortar mix design. The results have been indicated that the effect of OPS ash on flexural and compressive strength of cement mortar is not same. The deflection, load sustainability and time to failure for compressive strength have independent fluctuation of flexural strength. The positive and negative effect of OPS ash on mechanical properties of cement mortar has been observed. The morphology of crack failure has not been investigated. The work can be continued with many waste agriculture materials. Keywords: waste agriculture, deflection, load sustainability, time to failure.

Acid Resistance of Oil Palm Shell Lightweight Aggregate Concrete Containing Palm Oil Fuel Ash

Concern towards reducing waste disposed by Malaysian palm oil industry, palm oil fuel ash (POFA) and oil palm shell (OPS) that poses negative impact to the environment has initiated research on producing oil palm shell lightweight aggregate concrete (OPS LWAC) containing palm oil fuel ash. The present investigation looks into the effect of palm oil fuel ash content as partial cement replacement to compressive strength and acid resistance of oil palm shell lightweight aggregate concrete. Two types of mix, plain OPS LWAC and another one containing POFA as partial cement replacement have been used in this research. Cubes of 100 x 100 x 100 (mm) were water cured for 28 days before subjected to compressive strength test and acid resistance test. The findings indicate that suitable integration of POFA content would ensure occurrence of optimum pozzolanic reaction leading to densification of concrete internal structure which increases the compressive strength and better durability to acid attack. Integration of 20% POFA successfully assist concrete to achieve the highest compressive strength and exhibit superior resistance against acid attack compared to other mixes.

The Effect of Nanoparticles of Ordinary Portland Cement (OPC) on Compressive Strength of Concrete

The quality of a construction material satisfies stability of structure. Several additives have been innovated for improve quality of compressive strength of concrete. In this paper for enhancement of compressive strength of concrete, a simple method has been proposed. The kaolin and bentonite have been treated by heat for duration of 1 hour, with constant temperature. For kaolin 200 oC, 400 oC, 600 oC, 800 oC, 1000 oC and 1200 oC of heat, and for bentonite 200 oC, 400 oC, 600 oC, 800 oC of heat has been subjected. The kaolin and bentonite treated by heat have been proposed as additive for concrete. The objective is to introduce an additive to improve compressive strength of concrete. The microstructure of modified Ordinary Portland Cement (OPC) paste has been investigated by using Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffractometry (XRD). The results indicate that the best level of heat for produce additives from kaolin and bentonite, and illustrate quantity of additives for replace a portion of cement in concrete application. Modification of nanoparticles of cement paste during hydration has been discussed.

Using High Temperature for Improve Compressive Strength of Ordinary Portland Cement Paste (OPC) – A New Approach

Cement paste was replaced with kaolin-bentonite. The specimens were exposed to elevated temperature for 3 hours in a ceramic furnace and cooled down to room temperature. After cooling, the effect of kaolin-bentonite (particles sized of < 45μm) on hydration, rehydration, surface roughness and compressive strength of ordinary Portland cement (OPC) paste were investigated. Atomic Force Microscopy (AFM) was used to study surface roughness of OPC paste-additive mixture. The application of fire on OPC paste was analyzed. The results showed imposed heat (500 oC for 3 hours) accelerates the hydration process of OPC, and reduces setting time. Increased heat to 1000 oC, leads to zero compressive strength of specimens, the compressive strength of OPC continuously reduces after specimen has fully cooled down. A method for recovery of compressive strength of OPC after offing fire has been suggested. The method of offing fire has important effects on the compressive strength of concrete. The best results for specimen content are cement-kaolin-bentonite paste, exposure to 500 o C, after 90 days of curing, and cooling down in water. In this case the compressive strength has been increased around 60 % compared to not using additive and not exposing to heat.