จำนวน Repository ( 70 )
Use of disposed waste ash from landfills to replace Portland cement
In this study waste ash was utilized as a pozzolanic material in blended Portland cement in order to reduce negative environmental effects and landfill volume required to dispose of waste ash. The influence of waste ash namely palm oil fuel ash rice husk ash and fly ash on compressive strength and sulfate resistance in mortar were studied and evaluated by some accelerated short–term techniques in sodium sulfate solutions. Ordinary Portland cement (OPC) was partially replaced with ground palm oil fuel ash (POA) ground rice husk ash (RHA) and classified fly ash (FA). Single pozzolan and a blend of equal weight portions of POA RHA and FA were also used. The resistance to sulfate attack of mortar improves substantially with partial replacement of OPC with POA RHA and FA. The use of a blend of equal weight portions of FA and POA or RHA produced mixes with good strength and resistance to sulfate attack. POA RHA and FA have a high potential to be used as a pozzolanic material.
Strength and chloride resistance of blended Portland cement mortar containing palm oil fuel ash and fly ash
This paper presented a study on the strength and chloride resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground palm oil fuel ash (POA) and classified fly ash (FA). The mortar mixtures were made with Portland cement type I containing 0-40wt% FA and POA. FA and POA with 1wt%-3wt% retained on a sieve No.325 were used. The compressive strength and rapid chloride penetration depth of mortars were determined. The results reveal that the use of ternary blended cements produces good strength mortars. The use of the blend of FA and POA also produces high strength mortars and excellent resistance to chloride penetration owing to the synergic effect of FA and POA. A mathematical analysis and two-parameter polynomial model were presented to predict the compressive strength. The mathematical model correlated well with the experimental results. The computer 3-D graphics of strength of the ternary blended mortars were also constructed and could be used to aid the understanding and the proportioning of the blended system.
Strength, porosity and corrosion resistance of ternary blend Portland cement, rice husk ash and fly ash mortar
This paper presents a study of the strength porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground rice husk ash (RHA) and classified fly ash (fine fly ash FA). Compressive strength porosity and accelerated corrosion with impressed voltage (ACTIV) were tested. The results show that the use of ternary blend of OPC RHA and FA produces mortars with improved strengths at the low replacement level with RHA and FA and at the later age in comparison to that of OPC mortar. The porosity of mortar containing pozzolan reduces with the low replacement level of up to 20% of pozzolan but increases with the 40% replacement level. The chloride induced corrosion resistance of mortar as measured by ACTIV is however significantly improved with the use of both single pozzolan and the ternary blend OPC RHA and FA. The corrosion resistance of ternary blend mortar is higher than that of mortar containing single pozzolan. The use of ternary blend OPC RHA and FA is very effective in enhancing chloride induced corrosion of mortar.
การพัฒนาผนังบ้านดินสำเร็จรูปที่ต้านทานการชะล้างสูงและเป็นฉนวนป้องกันความร้อนที่ดีสำหรับอาคารอนุรักษ์พลังงานและสิ่งแวดล้อม
The objective of this research is to develop the precast adobe wall panel with high corrosion resistance and good thermal insulation. The ratio of Portland cement type1 clay rice husk ash straw rice husk waterproofed liquid and tap water was mixed and casted as same as the common concrete and reinforced by bamboo. From the results the proper prototype ratio of precast adobe wall panel was Portland cement type1: clay: rice husk ash: straw: rice husk: waterproofed liquid: tap water which equal to 1: 3: 0.3: 0.02: 0.02: 0.02: 0.4 by weight. The properties of the precast adobe wall panel prototype included density 1797 kg/m3 water absorption 16.70% bending strength 2.61 MPa compressive strength 21.40 MPa thermal conductivity coefficient 0.314 watt/m.Kelvin. Moreover the precast adobe wall panel prototype also was verified by TIS.2226-2548 with properties of impact resistance deflection and hardness in medium duty (MD) level. These straw and rice husk effected the precast adobe wall panel to decrease the density bending strength thermal conductivity coefficient and increase the compressive strength and water absorption.
การพัฒนาโครงสร้างเกรนต้านทานการสึกหรอของชิ้นงานความแข็งสูงพิเศษด้วยกระบวนการอบผนึก
This study developed the cemented tungsten carbide by steadily sintering at 1430 °C for one hour. The tungsten carbide structure is a long shape. Its grain size has a difference between width and length and there are high distribution of sizes and shapes. In comparison with the work piece which has the similar size of grain structure the milling duration of tungsten carbide is less even though the condition of WC-Co is the same (95% WC – 5% Co). When the sintering of 1400 °C with the identical milling duration is performed. It turned out that both grain structures of the tungsten carbide and the work piece are similar and their grain sizes are slightly different. However when the grain structures are almost the same and sphericity is increased the hardness and wear resistance will also be improved. Therefore the size of grain structure between 1.00 – 3.00 μm with the milling duration of 100 hours will provide a work piece that has a wear resistance according to international standard