scholarly journals Evaluation of Impact Resistance for Concrete Median Barrier Depending on Vehicle Curb Weight, Concrete Cover Depth and Level of Deterioration

2017 ◽  
Vol 30 (4) ◽  
pp. 297-306
Author(s):  
Jaeha Lee ◽  
◽  
Ilkeun Lee ◽  
Yoseok Jeong ◽  
Kyeongjin Kim ◽  
...  
Keyword(s):  
Impact Resistance ◽  
Concrete Cover ◽  
Cover Depth ◽  
Curb Weight

scholarly journals Efficient maintenance method for water supply facilities focused on the carbonation of concrete

2019 ◽  
Vol 14 (1) ◽  
pp. 178-188
Author(s):  
Masaki Fujita ◽  
Shoichi Iwasaki ◽  
Keinosuke Inoko ◽  
Kenji Hayashi
Keyword(s):  
Water Supply ◽  
Environmental Conditions ◽  
Surface Coating ◽  
Inhibitory Effect ◽  
Concrete Cover ◽  
Cover Depth ◽  
Concrete Deterioration ◽  
Inner Surface ◽  
The Impact ◽  
Published Research

Abstract In water supply facilities such as distribution reservoirs, the inner surface of reinforced concrete (RC) tanks is often coated with resin paint or the concrete cover depth is increased to protect the concrete from surface deterioration. However, there is little published research on carbonation – one of the main causes of concrete deterioration – in relation to RC tanks, leaving room for improvement with regard to methods for preventing surface deterioration. This study discusses the impact of surface coating and environmental conditions on the carbonation rate of concrete based on a survey of the present state of RC tanks of the Sapporo Waterworks Bureau. Coating was found to have an inhibitory effect on carbonation. Because the carbonation rate of concrete used for the inside and outside of RC tanks was slow, the sufficient concrete cover depth to protect rebar from carbonation while in service was found to be 75 mm for RC tanks without coating.

scholarly journals The Cover Depth Effect on Corrosion-Induced Deterioration of Reinforced Concrete Focusing on Water Penetration: Field Survey and Laboratory Study

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3478
Author(s):  
Shingo Asamoto ◽  
Junya Sato ◽  
Shinichiro Okazaki ◽  
Pang-jo Chun ◽  
Raktipong Sahamitmongkol ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Laboratory Study ◽  
Numerical Study ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Water Penetration ◽  
Depth Effect ◽  
Cover Depth ◽  
Oxygen Penetration

Reinforced concrete bridges were visually surveyed in Japan, Thailand, and Vietnam to study the deterioration caused by internal steel corrosion under different climates, focusing on the concrete cover depth. Spalling or cracking arising from corrosion is likely where water is supplied. According to prior studies and our surveys, a concrete cover depth of more than 40 mm was found to prevent spalling, regardless of environmental conditions and structure age. Because water supply at steel is a key corrosion factor, it was hypothesised that under natural conditions, the water penetration in concrete would remain at a depth of approximately 40 mm. Our laboratory study examined water penetration under drying and wetting conditions. The results also suggested that under periodic rainfall conditions, the threshold of water penetration was not exceeded. The numerical study indicated maximum moisture evaporation to facilitate oxygen diffusion occurred at a depth of approximately 30–40 mm unless the concrete was exposed to continuous drying for more than one month. It was experimentally and numerically concluded that an adequate cover depth of greater than 40 mm could inhibit moisture and oxygen penetration at the steel, which supported the survey findings of cover depth effect on a high resistance to corrosion-induced deterioration despite an increase in service life.

Pengaruh Kecepatan Putar Terhadap Hasil Coran pada Metode Pengecoran Sentrifugal dalam Pembuatan Produk Pisau Pakan Ternak dengan Material Ni-Hard1

2019 ◽  
Vol 11 (01) ◽  
pp. 1-7
Author(s):  
Roni Kusnowo ◽  
Kus Hanaldi
Keyword(s):  
Animal Feed ◽  
Centrifugal Casting ◽  
Impact Resistance ◽  
Literature Study ◽  
Gravity Casting ◽  
Friction Resistance ◽  
Optimal Speed ◽  
Mold Making

Animal feed knife is a tool that serves to cut and chop animal feed consisting of grass as the main ingredient with additives such as bran, herbs, centrate, cassava, tofu pulp and others. Therefore, as a cutting tool must have the properties of friction resistance, impact resistance, and have good sharpness, so that the material chosen is Ni-Hard 1. The use of centrifugal casting method was chosen because it has the advantage of being able to make castings with relatively thin thickness this is due to the influence of the centrifugal force on the distribution of metal liquids throughout the cavity in the mold. Case study in this study is the use of centrifugal casting methods as an alternative to gravity casting methods to overcome defects of misruns. This research was conducted to investigate the effect of speed on the formation of castings products. The method that was carried out began with a literature study on centrifugal casting, and continued by determining the material, the temperature of the cast is in the range 1250ºC - 1300ºC, and the type of mold. The next step is to do work drawings, pattern making, mold making, casting processes, fettling processes, and analysis. With variations in speed of 200 rpm, 300 rpm and 400 rpm, it can be seen the optimal speed for making this product. The results of this study obtained optimal speed at a speed of 300 rpm to make good quality of animal feed knife products.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

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