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Aptitude Questions and Answers - IndiaBIX
Aptitude questions and answers with detailed explanations for your competitive examinations, placement interviews, and various entrance tests.
⚡️Concrete Cover is also known as Spacers which is used to provide spacing at Slab, Column, Beam & foundation.
⚡️Application is very simple as place between Rebar (Reinforcement bar) and ground/wall.
✨There are four types of cover block or Spacers!
1. Slab Cover
2. Column & Beam Cover
3. Foundation Cover
4. Piling Cover
⚡️Why need covering
1. to protect the steel reinforcement bars ( rebars) from env't effect to prevent their corrosion .
2. To provide thermal insulation ,whiche protect the reinforcement bars from fire.
3. To give reinforcing bars sufficient embedding to enable them to be stressed with out slipping
https://t.me/engineer03
⚡️Application is very simple as place between Rebar (Reinforcement bar) and ground/wall.
✨There are four types of cover block or Spacers!
1. Slab Cover
2. Column & Beam Cover
3. Foundation Cover
4. Piling Cover
⚡️Why need covering
1. to protect the steel reinforcement bars ( rebars) from env't effect to prevent their corrosion .
2. To provide thermal insulation ,whiche protect the reinforcement bars from fire.
3. To give reinforcing bars sufficient embedding to enable them to be stressed with out slipping
https://t.me/engineer03
✨How is a reinforcement bar in hardened concrete structure exposed to corrosion??
⚡️ሙሉ በሙሉ ጥንካሬውን ያገኘ የ ኮንክሪት ስትራክቸር ውስጥ ያለ ወይም የተሰራበት reinforcement bar እንዴት ሊዝግ ይችላል? በምን ምክንያቶችስ ሊሆን ይችላል?
⚡️ሦስት መሰረታዊ የሆኑ ሁኔታዎች reinforcement ባራችንን በበቂ ሁኔታ ጥንካሬውን ባገኝ የ አርማታ ስትራክቸር ውስጥ ባለበት ሊያዝጉት ይችላሉ (corrosion እንዲፈጠር ሊያደርጉት ይችላሉ)
1,የመጀመሪያው carbonation ይባላል
:- እንደሚታወቀው concrete strongly alkaline nature አለው። ይህም የሆነበት ምክንያት Ca(OH)2 ስላለው። pH value ደግሞ about 13 ነው።
:- due to this high alkalinity nature ኮንክሪቱ reinforcement ባሩን ከ corrosion ለመከላከል a thin passivating layer በባሩ ዙሪያ በመፍጠር ብረቱን ከዝገት ይከላከላል። ይህም process passivation በመባል ይታወቃል።
:- as we know CO2 በራሱ reactive አይደለም። ግን in the pressence of moisture( እርጥበት) ወደ dilute carbonic acid ይቀየራል። ከዛም concrete form ያደረገውን passivating layer መብላት ወይም ማፈራረስ ይጀምራል። በመጨረሻም PH value ን ወደ 8.3 - 9 ያደርሰዋል። ልክ PH value ከ 11 ማነስ ሲጀምር ብረቱ በቀላሉ መዛግ ይጀምራል።
2,ሁለተኛው ደግሞ chloride attack ነው
:- በተመሳሳይ መንገድ ልክ carbonation passivating layer ን ማፈራረስ እንደሚችል chloride attack ም ያንን በበለጠ ማድረግ ይችላል።
:- chloride attack is more serious reason than any other
:- in the presence of water and oxygen, chloride can destroy the passivating layer and leads to corrosion.
:- chloride በቀላሉ ወደ ኮንክሪቱ ሊገባ ይችላል። ለምሳሌ በ cement,water,aggregate and sometimes from admixtures or from environment by diffusion.
3,ሶስተኛው በ electrochemical process ነው
:- ይሄኛው ደግሞ when there is a difference in electrical potential along the steel reinforcement in concrete.
:- ብረቱ ውስጥ አንደኛው part anode ሌላኛው part ደግሞ cathode ሲሆን ነው።
★ በስተመጨረሻም corrosion of reinforcement ለመከላከል ምን አይነት measurement መውሰድ እንዳለብን እንድትወያዩበት እጋብዛለው።
https://t.me/engineer03
⚡️ሙሉ በሙሉ ጥንካሬውን ያገኘ የ ኮንክሪት ስትራክቸር ውስጥ ያለ ወይም የተሰራበት reinforcement bar እንዴት ሊዝግ ይችላል? በምን ምክንያቶችስ ሊሆን ይችላል?
⚡️ሦስት መሰረታዊ የሆኑ ሁኔታዎች reinforcement ባራችንን በበቂ ሁኔታ ጥንካሬውን ባገኝ የ አርማታ ስትራክቸር ውስጥ ባለበት ሊያዝጉት ይችላሉ (corrosion እንዲፈጠር ሊያደርጉት ይችላሉ)
1,የመጀመሪያው carbonation ይባላል
:- እንደሚታወቀው concrete strongly alkaline nature አለው። ይህም የሆነበት ምክንያት Ca(OH)2 ስላለው። pH value ደግሞ about 13 ነው።
:- due to this high alkalinity nature ኮንክሪቱ reinforcement ባሩን ከ corrosion ለመከላከል a thin passivating layer በባሩ ዙሪያ በመፍጠር ብረቱን ከዝገት ይከላከላል። ይህም process passivation በመባል ይታወቃል።
:- as we know CO2 በራሱ reactive አይደለም። ግን in the pressence of moisture( እርጥበት) ወደ dilute carbonic acid ይቀየራል። ከዛም concrete form ያደረገውን passivating layer መብላት ወይም ማፈራረስ ይጀምራል። በመጨረሻም PH value ን ወደ 8.3 - 9 ያደርሰዋል። ልክ PH value ከ 11 ማነስ ሲጀምር ብረቱ በቀላሉ መዛግ ይጀምራል።
2,ሁለተኛው ደግሞ chloride attack ነው
:- በተመሳሳይ መንገድ ልክ carbonation passivating layer ን ማፈራረስ እንደሚችል chloride attack ም ያንን በበለጠ ማድረግ ይችላል።
:- chloride attack is more serious reason than any other
:- in the presence of water and oxygen, chloride can destroy the passivating layer and leads to corrosion.
:- chloride በቀላሉ ወደ ኮንክሪቱ ሊገባ ይችላል። ለምሳሌ በ cement,water,aggregate and sometimes from admixtures or from environment by diffusion.
3,ሶስተኛው በ electrochemical process ነው
:- ይሄኛው ደግሞ when there is a difference in electrical potential along the steel reinforcement in concrete.
:- ብረቱ ውስጥ አንደኛው part anode ሌላኛው part ደግሞ cathode ሲሆን ነው።
★ በስተመጨረሻም corrosion of reinforcement ለመከላከል ምን አይነት measurement መውሰድ እንዳለብን እንድትወያዩበት እጋብዛለው።
https://t.me/engineer03
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@engineer03
http://www.Indiabix.com በዚህ ደግሞ ማንኛውንም ጥያቄና መልስ ታገኛላችሁ!
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