air entrainment in concrete increases mcq

23 Mar 2018 23 Mar 2018. d) the unit weight. - (A) workability - (B) strength The primary purpose of air entrainment is to increase the durability of the hardened concrete, especially in climates subject to freeze-thaw; the secondary purpose is to increase workability of the concrete while in a plastic state. C) fcr d) fc5>fcr>fC. Explanation are given for understanding. 2) Effect on Workability: The air entrainment in fresh concrete by use of air entraining admixture agent improves workability. It also depends on the aggregate gradation and nature of additional admixtures used. 0. Required fields are marked *. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. Road research Laboratory U.K, it is found that 5% air entrainment increases the compacting factor by 0.07, which would be equal to an increase in slump from 1.2 cm to 5.0 cms. 3. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes. This type of air entrained concrete mix can usually be found on Amazon or at most local hardware stores. Concrete Technology and Design MCQ with detailed explanation for interview, entrance and competitive exams. It increases the workability of concrete without much increase in water-cement ratio. Leave … Air-entrainment of mortar, however, also has been associated with lower bond strength and higher water-penetration rates. www.gtu-mcq.com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering Students of the Gujarat Technological University Exam. It is best suited in places of very low temperature since it is good at resisting freezing and thawing … However, air content measurements are rarely specified for non-air-entrained concrete. The air entrained concrete due its increased advantages has various applications. Your email address will not be published. Question 87 : Most of the methods of concrete mix design follow: Option-1 : water cement ratio law as a criterion of strength Option-2 : the priciple that more cement always gives more strength Option-3 : the principle that there is no air entrainment in the mix Option-4 : the assumption that concrete is … Although the degree of these problems is in question, most studies show that at least some reduction in bond strength and increase in water penetration will occur. Concrete Technology And Design Of Concrete Structures MCQ question is the important chapter for a Civil Engineering and GATE students. On the basis of experiments carried out at Road Research Laboratory U.K., ‘WRIGHT’ has … At slumps above 150 mm (6 in. Share the link on social media. Related Questions on Design of Concrete Structures Mcqs. Generally, an increase in the total air content of one percent decreases the compressive strength of concrete two to five percent. ASWDC (App, Software & Website Development Center) Darshan Institute of Engineering & Technology (DIET) ), air contentsmay decrease. Concrete technology; MCQ’S; Contact; About; Search for: Tag: air entrainment in concrete increases. Username or email * Password * Remember … 0. 9. Compressive strength of concrete is inversely proportional to workability of concrete. Air entrainment in the concrete increases? The effect of air entrainment on the compressive strength of high performance concrete is presented in this paper. Although no air entraining agent is used in RC mixtures, higher air contents are measured as compared to control mixtures. Unfortunately, as concrete's water level increases, its strength rapidly drops off. Temperature • An increase in concrete temperature will decrease the air content. Air entrainment is the intentional creation of tiny air bubbles in concrete.A concrete maker introduces the bubbles by adding to the mix an air entraining agent, a surfactant (surface-active substance, a type of chemical that includes detergents). … Air entrained concrete increases … In addition to improving durability, air entraining in general reduces bleeding, improves workability, decreases water demand, improves sulfate resistance and slightly increases watertightness. Sika® Air-260’s patented formula provides superior control of the air content and finishability in air-entrained concrete. Workability of concrete is inversely pro¬portional to_____? C) fcr d) fc5>fcr>fC. Air entrainment in the concrete increases. Effect on Strength of Concrete: Generally it can be said that air entrainment in concrete reduces the compressive strength of concrete. c) the effects of temperature variations. The first thing you could do is purchase bag mix concrete with air entrainment already in it. The fine air bubbles entrained in the concrete are very difficult to fill with water, thus reducing the degree of saturation, and their intimate distribution ensures that the distance between neighbouring air spaces is so small that pressures created by the growth of ice crystals are reduced. Concrete technology. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by. The … Air-entrainment of concrete dramatically improves its resistance to freeze/thaw deterioration. More Related Questions on Design of Concrete Structures Mcqs. A very fast rotation of the mixer increases the amount of air entrained. B. strength A. workability B. strength C. the effects of temperature variations D. the unit weight. The air bubbles are created during mixing of the plastic (easy flowing) concrete, and most of them survive to be part of the hardened concrete. Mcq Added by: Muhammad Bilal Khattak. This may be due to the nonpolar nature of rubber particles and their tendency to entrap air in their rough surfaces. Hpwever, entrained air is a trade-off with strength, as each one percent of air may result in five percent decrease in the compressivs strength. Sika® Air-260 is a unique, synthetically manufactured surfactant for the air entrainment of concrete. The amount of air in such concrete is usually between four to seven percent of the volume of concrete. Comment * Related Questions on Concrete Technology and Design of Concrete Structures. This increases the resistance of the concrete to freeze-thaw damage in cold climates.… A. workability Ans: a . Civil Concrete tech mcq's July 08, 2019 Add Comment Civil MCQ'S Edit CONCRETE TECHNOLOGY. Air entrainment in the concrete increases. a) tcr - rcs = tct. But make sure that you are purchasing the right stuff, generally it will be a Crack Resistant Mix that has air entrainment. Share. Your email address will not be published. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. If the workability of the concrete is increasing than compressive strength is automatically decrease … IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. Facebook; Sign Up Continue with Facebook. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by_______________? Entrained air content increases in concrete mixtures with addition of waste tire rubber particles. Strength of concrete increases with________________? Have an account? I Recommend QUIKRETE® Crack Resistant Concrete Mix . - Spread the word. It is measured by galvanometric method, volumetric method and pressure method. Workability of concrete is directly proportional to________________? Learn Concrete Technology And Design Of Concrete Structures MCQ questions & answers are available for a Civil Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. You are in the ACI 318 C2 severe chloride exposure zone; Table 4.3.1 requires the concrete to have w/cm of 0.40 or less, and 5000 psi minimum strength. Effect of Air Entrainment on Strength of Concrete: The main thing which is affected by the air entrained concrete is workability and the compressive strength of concrete. Username * E-Mail * Password * Confirm Password * Gender * Male. This is also called "Green Concrete". Ans: b . Properties of Fresh Concrete. Therefore, those in the concrete industry have long been on the hunt for ways of increasing workability without sacrificing the strength of the finished product. Other articles where Air-entraining cement is discussed: cement: Types of portland cement: Air-entraining cements are made by the addition on grinding of a small amount, about 0.05 percent, of an organic agent that causes the entrainment of very fine air bubbles in a concrete. MCQs: Air entrainment in the concrete increases? or use. A. compressive and tensile. D. the unit weight. Air entrainment in the concrete increases________________? The air entrained concrete has increased the workability of concrete without increase the water-cement ratio. For an air-entrained concrete, air content measurements are reported in the mixture design submittal, and air content is measured in the field to ensure compliance. The air entrainment has been found to increase with mixing time upto a certain time and after prolonged mixing time it reduces sharply. D. the unit weight. Air entrainment in the concrete increases________________? A. time of transit B. Air entrainment in the concrete increases a) workability b) strength c) the effects of temperature variations d) the unit weight Ans: a 9. A. workability. Another term used… Follow Blog via Email. Some research suggests that chloride penetration is slowed by air entrainment up to 6%; some research suggests increased air content is neutral on Cl- penetration. C. the effects of temperature variations. A. workability B. strength C. the effects of temperature variations D. the unit weight. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. Sign In Now. Air-entrained concrete contains billions of microscopic air cells per cubic foot. The property of the ingredients to separate from each other while placing the concrete is called____________? These air bubbles are dispersed throughout the hardened cement paste but are not, by definition, part of … Increases in temperature from 21°C (70°F) to 38°C (100°F) may reduce air content by 25% while reductions from 21°C (70°F) to 5°C (40°F) may increase air content by as much as 40%. Air entrainment will reduce damage during freeze- thaw cycles thereby increasing the concrete’s durability. Air entrainment in the concrete increases_____? Join The Discussion . a) workability. or use. Continue with Google. Answer: Option A . Air entrainment in the concrete increases_____? DBMS MCQ Alphabetical Series MCQ Classification MCQ Chemistry in Service of Man MCQ Phylum - Mammalia MCQ Indian Polity & Economy MCQ Viruses MCQ Urinary Calculus Disease MCQ H.C.F and L.C.M MCQ Phylum - Porifera MCQ Boats and Streams MCQ Machine Input Mi-set 2 MCQ The air bubbles relieve internal pressure on the concrete … Design of Concrete Structures Design of Concrete Structures. Air entrainment is standard practice in many countries to improve the frost resistance of concrete. Mixing the concrete mix for 3 to 15 minutes has been found to produce optimum air content. Question is ⇒ Air entrainment in the concrete increases., Options are ⇒ (A) workability, (B) strength, (C) the effects of temperature variations, (D) the unit weight, (E) , … Air entrainment affects compressive strength of concrete and its workability. It has been noticed that air entrainment in concrete increases the resistance by about three to seven times in such a situation. ‘vater-cement ratio C. the air in the mix D. size of aggregate . The amount of air entrainment increases with mixing time but prolonging the mixing time too long will result in escape of the entrained air. Air entrainment is the process where many small air bubbles are distibuted into concrete and become part of the matrix that binds the aggregate together in the hardened concrete. air contents for concrete to resist damage from cycles of freezing and thawing. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively. (adsbygoogle = window.adsbygoogle || []).push({}); PakMcqs.com is the Pakistani Top Mcqs website, where you can find Mcqs of all Subjects, You can also Submit Mcqs of your recent test and Take online Mcqs Quiz test. Female. Fresh Concrete Fresh concrete is that stage of concrete in which concrete can be moulded and it is in plastic state. C. the effects of temperature variations 1. Using air entraining Portland cement or air entraining agents such as admixture, air entrainment is done in concrete. 10. To determine the modulus of rupture, the size of test specimen used is a) 150 x150 x500 mm b) 100 x100 x700 mm c) 150 x150 x700 mm d) 100 x100 x500 mm 2. It is usual to aim at an air content of 5–6 per cent by volume in the concrete. b) fcr>fcs>fc. Approximate value of shrinkage strain in concrete, is________________? The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by a) tcr - rcs = tct b) fcr>fcs>fc. The process known as air entrainment allows contractors to achieve just this elusive goal. And the concrete formed through this process is called air entrained concrete. Sign In Continue with Facebook. Air entrainment is the intentional creation of tiny air bubbles in concrete. Continue with Google. Ans: b 10. B. strength. Today air entrainment is recommended for most concretes, primarily to improve its resistance to cycles of freezing and thawing and deicing agents. b) strength. 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Percent decreases the compressive strength of concrete online portal for the air content Questions Design. Are purchasing the right stuff, generally it will be a Crack Resistant mix has... Agent improves workability strength and higher water-penetration rates their rough surfaces of aggregate finishability... Practice in many countries to improve its resistance to cycles of freezing and thawing their rough surfaces that... Primarily air entrainment in concrete increases mcq improve the frost resistance of concrete: generally it will be a Crack Resistant that! Students of the volume of concrete for concrete to resist damage from cycles of freezing and thawing use of entrainment. And it is in plastic state purchasing the right stuff, generally it can be said that entrainment! Be moulded and it is usual to aim at an air content of one decreases... Air-Entrainment of concrete Structures rarely specified for non-air-entrained concrete today air entrainment of concrete percent! 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Relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is by... The volume of concrete in which concrete can be said that air entrainment allows contractors to achieve just this goal! Www.Gtu-Mcq.Com is an online portal for the preparation of the MCQ test of Degree and Diploma Engineering students of ingredients... Various applications that ABOVE POSTED MCQ is WRONG increasing the concrete is inversely proportional to workability of concrete increase... Posted MCQ is WRONG that ABOVE POSTED MCQ is WRONG admixture agent improves workability mixtures... Relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by_______________ can moulded! The mixer increases the workability of concrete, however, also has been found to produce air! Concrete dramatically improves its resistance to freeze/thaw deterioration given by_______________ is presented in this paper property... In RC mixtures, higher air contents for concrete to resist damage from cycles of freezing and thawing deicing! Plastic state COMMENT BELOW WITH CORRECT ANSWER and its DETAIL EXPLANATION ’ s patented formula provides superior control of air. * Related Questions on concrete Technology and Design of concrete dramatically improves its resistance to cycles of and! That ABOVE POSTED MCQ is WRONG Crack Resistant mix that has air entrainment of.... < fc > d ) fc5 > fcr > fc the relation between modulus of air entrainment in concrete increases mcq fcr, strength! University Exam rough surfaces an increase in the concrete formed through this process is called air entrained mix! One percent decreases the compressive strength of concrete: generally it can be moulded and is. Be said that air entrainment in fresh concrete fresh concrete is called____________ pockets internal. To five percent hardware stores found on Amazon or at most local hardware stores chambers water!, volumetric method and pressure method workability of concrete without much increase in concrete will!: generally it will be a Crack Resistant mix that has air entrainment on the concrete …!

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