จำนวน Repository ( 52 )

สมบัติทางวิศวกรรมของบล็อคปูพื้นคอนกรีตพรุนจากผิวทางแอสฟัลต์เก่านำมาใช้ใหม่โดยการแทนที่มวลรวมหยาบ
สมบัติทางวิศวกรรมของบล็อคปูพื้นคอนกรีตพรุนจากผิวทางแอสฟัลต์เก่านำมาใช้ใหม่โดยการแทนที่มวลรวมหยาบ

This research aimed to study the use of coarse aggregate obtained from removing old recycled asphalt pavement (RAP) in the production of the porous concrete paving block. Crushing and size separation of the coarse aggregate by using standard sieve size by selected the gradation size of the coarse aggregate that passed to sieve size 1/2” and retained on sieve size 3/8” and other that passed to sieve size 3/8” and retained on sieve size No.4 by mixing ratio 50 : 50 of the mass as replaced natural coarse aggregate. Portland cement quantity about 18% and 20% by weight of the aggregate. The water to cement ratio was 0.30 and 0.35 respectively. Compressive strength flexural strength and water permeability were investigated. The results showed that the cement content and water to cement ratio was influenced the strength properties and water permeability rate of the porous concrete paving block. The porous concrete paving block mixed with higher cement content (20%) had the compressive strength at the age of 28 days increased by 16-24% when compared with lower cement content (18%). On the other hand the water permeability rate decreased by 5.1-8.1%.

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กำลังอัดความสามารถเก็บกักคลอไรด์และสัมประสิทธ์การแพร่คลอไรด์ของคอนกรีตผสมเถ้าก้นเตาบดละเอียดและผงหินปูน
กำลังอัดความสามารถเก็บกักคลอไรด์และสัมประสิทธ์การแพร่คลอไรด์ของคอนกรีตผสมเถ้าก้นเตาบดละเอียดและผงหินปูน

This research was aimed to study the compressive strength chloride binding capacity and chloride diffusion coefficient of concrete replaced by ground bottom ash (GBA) and limestone powder in ordinary Portland cement (OPC). The water to binder ratios were 0.55. The results showed that the compressive strength of concrete with GBA was lesser than that of OPC concrete at 28 days. Also the compressive strength of concrete with limestone powder was close to that of OPC concrete and compressive strength could develop of concrete with GBA 20% and 30% higher than that of OPC concrete at 56 days. Moreover the total chloride of the concrete containing GBA and limestone powder was less than that of OPC concrete. The chloride penetration of the concrete containing GBA and limestone powder was less than that of OPC concrete. The chloride binding capacity of the concrete made with ground bottom ash and limestone powder were higher than that of OPC concrete. Finally the chloride diffusion coefficient of the concrete containing GBA and limestone powder was less than that of OPC concrete.

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การเสริมกำลังคานลึกคอนกรีตเสริมเหล็กที่เสื่อมสภาพเนื่องจากคลอไรด์ด้วยแผ่นคาร์บอนไฟเบอร์
การเสริมกำลังคานลึกคอนกรีตเสริมเหล็กที่เสื่อมสภาพเนื่องจากคลอไรด์ด้วยแผ่นคาร์บอนไฟเบอร์

Deterioration of reinforced concrete deep beam structure caused by chloride is severe andtakes up wide area even though the structure is not exposed to sea water or brackish water. Even the structure which is far from sea water or brackish water is affected by this problem.When the reinforced concreate deep beam structure is affected by chloride steel reinforced inside the structure is corroded resulting in reducing the cross-sectional area of the reinforced steel affecting load capacity deflection and beam failure. If there is no repair or strengthening such capabilities are continuously reduced until it is no longer safe to use the beam. Therefore it is necessary to repair or strengthening the deteriorated structure to be safely used. This research investigated strengthening of deteriorated reinforced concrete deep beam caused by chloride with 4 formats of carbon Fiber sheets to seek guidelines for the most efficient strengthening. The resultshowed that the strengthening by the 4 format of carbon fiber sheet could increase ultimate loadcapability yet could not improve ductility of the deteriorated beam to become close to the beamthat is not deteriorated. The strengthening that could increase the maximum ultimate load capability was the table format strengthening. In addition the strengthening that the carbon fiber making 45 degrees with the length of the beam could best prevent diagonal cracks.

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คุณสมบัติเชิงกลของคอนกรีตมวลเบาผสมวัสดุปอซโซลาน
คุณสมบัติเชิงกลของคอนกรีตมวลเบาผสมวัสดุปอซโซลาน

This research study the effect of pozzolanic materials on light weight concrete by replacement cement with fly ash and Meta kaolin which affect the properties of concrete by using pumics aggregate. Coarse in aerated concrete and consider mechanical properties. Aerated concrete replacement cement by fly ash 20% 35% and 50% respectively and meta-kaolin is replaced. From the results it was found that the compressive strength of light weight concrete at 28 days w/b = 0.55 was higher than that of every 14 days of cement and cement cement replacement by fly ash 50% highest value compressive strength. More than all the ingredients replaced with fly ash and Meta kaolin. When considering the flexural strength of replacement cement with 10% by Meta kaolin the maximum flexural strength of 80 ksc was higher than that of control concrete and all other ingradient. Experimental tensile strength at 28 days result found that replacement cement by fly ash at 35% gave the highest tensile strength of 28 ksc and gave higher tensile strength than all other ingradient. From the impact strength test at age 28 days it was found that the replacement cement 35% by fly ash gave the highest impact strength of 92.00 joule than the 20% and 50% respectively and higher impact strength than that of all kaolin. Except for control concrete.

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การรับแรงกระแทกของคอนกรีตผสมปอซโซลานโดยระบบสามประสาน
การรับแรงกระแทกของคอนกรีตผสมปอซโซลานโดยระบบสามประสาน

This research study to the effect of pozzolanic materials by replacement cement by fly ash and Meta kaolin which affect the mechanical and physical properties of concrete. According to Standard test such as Compressive strength flexural strength and impact strength. The replacement cement by fly ash was 15% 30% and 45% respectively and replacement cement by meta-kaolin was 10% 15% and 20% respectively. The results showed that the compressive strength of concrete at 28 days. When considered ratio w/b = 0.40 was higher than w/b = 0.45 all ingredient. The replacement cement by fly ash was the most effective. 10% (375 ksc) 15% (362 ksc) and 20% (354 ksc) respectively. The replacement cement by meta-kaolin gave the highest flexural strength of 41 ksc higher than control mixed concrete and all other ingredient. At the age of 28 days The replacement cement by meta-kaolin was 10 percent result to the highest impact strength was 11 joule which was close to that of fly ash by 30 percent give value was 110 joules and more than replacement cement by meta-kaolin was 15% (100 joule) and 20% (95 joule). It can be concluded that the increase in meta-kaolin content result to compressive strength will reduce flexural strength and impact strength. As the amount of fly ash increased the compressive strength increased. flexural strength and impact strength Increased value.

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