Performance of Cement Boards in Presence of Waste Paper

The possibility of using waste paper in manufacturing of cement board has been investigated in this paper. Cement fiber ratio and pressure is the two variables in this experimental work. Samples were prepared with fiber/cement ratios of 5:95, 15:85 and 25:75 by weight. Every mixing ratio was divided in seven sub categories depending on the pressure of 0, 1.4, 2.4, 4.2, 5.5 6.9 and 8.3 MPa. Three boards were prepared for each category to evaluate the mechanical and physical properties of the boards according to ASTM standard. It is observed that the mechanical and physical properties of the board are directly influenced with pressure. However, the flexural strength and modulus of rupture were decreased with an increase of the amount of waste paper in the board. Five percent addition of waste paper exhibits the best performance of cement board in all aspect. The optimum production condition was obtained when the fiber content and pressure were 5% and 6.9 MPa respectively. At this optimum condition the prepared cement board satisfies the flexural strength requirement for Grade 2 type cement board according to ASTM C 1186

Power electronics : circuits, devices, and applications/ Rashid

xx, 584 hal.; 27 cm

Power electronics : circuits, devices, and applications/ Rashid

xx, 584 hal.; 27 cm

Comparison of Soil properties between Normal Land and Waste Dump Site

Geotechnical aspects and properties of the soil from the waste dump site sometimes show diverted behavior in comparison with normal land site. Soil from waste dump site shows abrupt nature and it may be acidic or alkaline based on the categories of the effluent that are being dumped on the top soil. When the soil treated with waste, it shows different nature than normal condition due to penetration of Leachate. This study aims to investigate into the effect of pH on the geotechnical properties of soil of normal land and waste dump sites and comparison between them based on the tests and considerations presented in this paper. To demonstrate this experiment, disturbed and undisturbed soil samples were collected from some selected locations of Khulna region. Experiments were conducted following the ASTM (2004) methods. The obtained results show that pH has a prominent influence on geotechnical properties including Specific Gravity, Plastic Limit (PL), Liquid Limit (LL), Shrinkage Limit (SL), Moisture Content, Undrained shear strength and preconsolidation stress of soil samples. Based on the test results it is seen that for the normal land soil show different behavior than the soil from dump site. Soil from dump site may range pH below 7 to upper 7, but for the normal land soil it shows always greater than 7. For this basic difference sometimes some properties of these two did not well match. Therefore, this paper provides insight regarding how the geotechnical properties of soil change with pH

Combining EBR CFRP sheet with prestressed NSM steel strands to enhance the structural behavior of prestressed concrete beams

In this study, a combined strengthening technique is used to improve the flexural performance of prestressed concrete beams using CFRP sheets as EBR and prestressed steel strands as NSM. Seven prestressed beams were tested under four-point loading with one control specimen, one EBR CFRP sheet strengthened specimen, one NSM steel strand without prestress strengthened specimen and four specimens strengthened with a combination of EBR CFRP sheet and NSM steel strands prestressed from 0% to 70% of their tensile strength. The flexural responses and failure modes of the specimens were investigated and the variations due to the level of prestressing force in the PNSM steel strands were also assessed. A finite element model (FEM) was developed using ABAQUS to verify the flexural responses of the strengthened specimens. The test results revealed that the combined strengthening technique remarkably enhanced the flexural performance of the specimens. The serviceability, first crack, yield, and ultimate load capacities improved up to 44%, 49%, 55% and 70%, respectively when compared with the control specimen. The combined technique also ensured the flexural failure of the specimens with significant enhancement in stiffness and energy absorption. The results of the FEM model exhibited excellent agreement with the experimental results