The workability of concrete is defined as the. Pick up the incorrect statement from the following : a. Tricalcium silicate (C3S) hydrates rapidlyb. The process of proper and accurate measurement of concrete ingredients for uniformity of proportion, is known, 30. The strength and durability of concrete depends upon, 2. If the workability of the concrete … Thin particlesb. It meets the requirements of ASTM C 260, AASHTO M 154 and CRD-C 13. Workability of concrete increases. It is claimed that, the place-ability of an air entrained concrete having 7.5 cm slump is better than a non-air entrained concrete with a slump of 12.5 cm. Lost your password? vacuum concrete [B]. generates less heat of hydrationc. for the mcq The entrained concrete is used in lining walls and roofs for making The water content for an air-entrained mix will be 3 to 5 gallons per cubic yard less than for a non-air-entrained mix having the same slump. Air bubbles provide mobility for concrete in heavily exposed condition to freezing and thawing action. The size, spacing and quantity of these air bubbles has an effect on a number of the properties of both the fresh and hardened concrete. 1 :3 :6b. To prevent segregation, the maximum height for placing concrete, isa. 4. The minimum percentage of chemical ingredient of cement is that of, a. magnesium oxideb. The entrapped air that remains in the mix creates an air void. The water content for an air-entrained mix will be 3 to 5 gallons per cubic yard less than for a non-air-entrained mix having the same slump. decreases workabilityc. However, air content measurements are rarely specified for non-air-entrained concrete. Correct Answer. Efflorescence im cement is caused dim to an excess of, a. aluminab. Answer=> c. 54. 13.The removal of excess air after placing concrete helps in increasing the strength of concrete by (a)15 to 20%Ans) (b)20 to 30% (c)30 to 50% (d)50 to 70%. medium sandD. Define air-entrained concrete. Light weight concrete possesses __________. c. Separation of water or water-cement mixture from the freshly mixed concrete. MasterAir AE 90 air-entraining admixture is for use in concrete mixtures. Answer=> c. 54. Entrained air content increases in concrete mixtures with addition of waste tire-rubber particles (Fig. 4. 60 minutesD. Electrical Engineering. Q: How does hard-troweled air-entrainment impact strong concrete? 40 nom to 50 mmd. These air bubbles act as flexible ball bearings and modify the properties of plastic concrete (such as workability, segregation, bleeding and finishing quality. According to IS: 4561978, the flexural strength of concrete is ... I.C Engines Multiple Choice Questions with Answers - Set 02. An aggregate is said to be flaky if its least dimension is less than, 26. increases strength, 38. Wp and Wf are the weights of a cylinder containing partially compacted and fully compacted concrete. 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. નો ફાઈન કોન્ક્રીટ ની ઘનતા વજન માં હળવા એગ્રીગેટ સાથે _________kg/m3 હોય છે ? For given water content, workability decreases if the concrete aggregates contain an excess of, a. Reduced bleeding and segregation and reduction of water cement ratio reduces the overall permeability of the concrete. a. Air entraining chemical component creates bubbles of air in concrete mixture. 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. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is, 55. You will receive a link and will create a new password via email. The need for fundamental research regarding the mechanism by which entrained air functions is suggested and methods of tests are out- lined. sodium chloridesc. Automobile Engineering. If a concrete slab does not meet the required air-entrainment, can the slab be rejected entiriely? 1 : 1: 2D. Air-entrained concrete is produced using air-entraining portland cement, or by the introduction of air-entraining agents, under careful engineering supervision, as the concrete is … These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes. causes initial setting and early strength of cementd. For road pavements, the cement generally used, is, 16. Workability of concrete increases. Workability of concrete is measured by (A) Vicat apparatus test (B) Slump test (C) Minimum void method (D) Talbot Richard test. Since air entrained concrete is m o r e cohesive and workable than non-air entrained, there is not as much danger of segregation and air p o c k e t s. Ac c o rd i n g l y, vibration need not be prolonged. Mechanical Engineering. Flaky particles, 8. Hence the production of air entrained concrete is very difficult. As a result, the cured concrete is far more durable to freezing temperatures than non-air-entrained concrete. 75 minutes, 74. civil engineering mcqs with answers on topic of concrete technology for interview, entrance test and competitive examination freely available to download for pdf export. 23.4). Chemical Engineering. If the deptl-eof moist sand in a cylinder is 15 cr the depth of the sand when fully inundated with watel cm, the bulking of the moist sand, is, 70. (d)Sawdust concrete. Another related use is for deicer-scaling resistance. 1 : 2 : 4B. is the answer among Neither (A) Nor (B),BOth (A) and (B). 65. He is now asking that the entire slab be removed and replaced a day later? a. 7. (d)Sawdust concrete. Electronics Engineering . A concrete using an air entrained cement. 1 : 1 : 2, 71. The high strength of rapid hardening cement at early stage, is due to its, 36. (i) and (iv) C. (ii) and (iii) D. (iii) and (iv) Answer: Option A Air entrained concrete is very common in a cold climate. Civil Engineering. As to appearance, air entrained concrete has an unusually creamy, fatty look. Air voids, however, also improve the workability of concrete. લાઈટ વેઇટ કોન્ક્રીટ કેવી લાક્ષ્નીકતા ધરાવે છે ? The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds, 31. decreases the strength of concretec. 30% b. pressure compaction of the bags on lower layersd. Particles of 0.002 mm size are that of, 79. b. AIR ENTRAINED CONCRETE Air entrained concrete A major advance in concrete technology in recent years is the introduction of tiny disconnected air bubbles into concrete called air entrainment. 3. The entrainment of air in fresh concrete improves its workability. The standard sand now a days used in India, is obtained from, c. prevents the loss of water by evaporation, 24. Air-entrained concrete contains billions of microscopic air cells per cubic foot. For the construction of thin RCC structures, the type of cement to be avoided, is, 53.A concrete using an air entrained cement, a. has strength less than 10% to 15%b. Elongated particlesd. Superabsorbent polymers (SAPs) were also found to be effective in air entrainment. The strength of air-entrained concrete depends on the water/cement ratio as it does in non-air-entrained concrete. However it provides no different R value than standard concrete. Better place-ability of air entrained concrete results in more homogeneous concrete with least segregation, bleeding and honeycombing. Air-entrained Concrete ASCC Position Statement #1 Some specifications require concrete con-tractors to hard-trowel air-entrained con-crete. Admixtures make concrete acid proofd. burning at high-temperaturec. સિમેન્ટ કોંક્રિટ, જ્યાંથી અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે છે, તેને ________ કહેવામાં આવે છે? 7.2.6 AIR ENTRAINMENT. 30 minutesB. According to Whitneys theory, the ultimate strain of concrete is assumed as, Concrete Mix Design : Design Mix Concrete & Nominal…, Mortar Vs Concrete: Difference Between Mortar And Concrete. These air-entrained agents in concrete generate millions of non-coalescing air bubbles, These air bubbles act as flexible ball bearings and will modify the properties of plastic concrete regarding workability , segregation, bleeding, and finishing quality of concrete. 1 :2 :4d. calcium chorides, a. volume of water to that of cementb. 30 mm to 40 mmc. both A and B of the above, 61. 14. between 350 to 600 kg/cm2C. The main object of compaction of concrete, is: c. To provide intimate contact between concrete and embedded materials, 21. 3. The mechanism of entraining concrete with air is presented to focus on the instability of the air bubbles while concrete is in a fresh state in terms of the effect of the pumping operation and the air bubble system. a) By cellular construction. The air entrained concrete is manufactured by introduction of any air entraining agents or using air entrained cement which is in turn manufactured by inter grinding air entraining agents to clinkers formed. The air voids provide pressure relief sites during a freeze event, allowing the water inside the concrete to freeze without inducing large internal stresses. thin and heavily reinforcedd. MCQs of Unit-6 Special Concrete & Concreting Techniques, 12. low heat cementd. Air-entrained concrete is produced through the use of air-entraining portland cement, or by the introduction of air-entraining agents, under careful engineering supervision as the concrete is. that: “Concrete for slabs to receive a hard-troweled finish shall not contain an air-entraining admixture or have total air content greater than 3 percent.” “Guide to Concrete Floor and Slab Construction (ACI 302.1R-15)” provides the rationale behind this specifica-tion requirement in Section 8.4.7: “Air-entraining … a. Air-entrained concrete contains billions of microscopic air cells per cubic foot. Internal friction between the ingredients of concrete, is decreased by using, a. increases workabilityb. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is. Because de-laminations are considered to be a construction defect, the contractor is expected to pay for the repairs, even though the designer specified the use of the air-entrained concrete A: It’s pretty well known in the concrete industry that hard-troweled surfaces and air-entrained concrete don’t mix. none of these, 64. Lime : Silica : Alumina : Iron oxide : 63 : 22 : 6 : 3, b. Silica : Lime : Alumina : Iron oxide : 63 : 22 : 6 : 3, c. Alumina : Silica : Lime : Iron oxide : 63 : 22 : 6 : 3, d. Iron oxide : Alumina : Silica : Lime : 63 : 22 : 6 : 3, 32. Advantages. alkalis. sodium carbonates and bicarbonatesd. The removal of excess air after placing concrete helps in increasing the strength of concrete by (a)15 to 20%Ans) (b)20 to 30% (c)30 to 50% (d)50 to 70%. Concrete is unsuitable for compaction by a vibrator if it is. 10 cm, 30 cm, 20 cmc. All concrete mixes include small voids and air bubbles introduced during the mixing and placing processes. Air Entrained Concrete. The bulk density of aggregates, depends upon. The ratio of various ingredients (cement, sand, aggregates) in concrete of grade M 200, is, A. Proper vibration techniques can be helpful in removing entrapped air. b) By using no fines concrete. Types Of Grouting In Construction | Advantages & Application Of Grouting, Top Civil Engineering Project Topics For Final Year Students, How To Calculate Unit Weight Of Steel Bars. 14.The cement concrete prepared by mixing aluminium in it , is called (a)Air entrained concrete (b)Cellular concrete (c)Aerated concrete (d)Any one of these(Ans) 14.The cement concrete prepared by mixing aluminium in it , is called (a)Air entrained concrete (b)Cellular concrete (c)Aerated concrete (d)Any one of these(Ans) Accordingly, vibration need not be prolonged. below 200 kg/cm2, a. full capacity of the ware houseb. The risks associated with this requirement include: 1) increased probability of delamination or blistering; 2) reduction in surface air content; and 3) change in hardened air void parameters. Factor # 2. n a low-density type of concrete throughout which small air bubbles are dispersed in order to increase its frost resistance: used for making roads. It was first used in early 1930 especially in USA. This natural air is known as entrapped air. 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 … rapid hardening cementc. 13. has more resistance to weatheringc. Pick up the correct proportions of chemical ingredients of cement, a. Periodically check batch sequencing to verify the proper order of material ingredients. Entrapped air is created during improper mixing, consolidating and placement of the concrete. silicad. 1 : 2 : 4 mixd. Higher workability of concrete is required if the structure is, a. made with cement concreteb. However, if the owner decides to use air-entrained concrete, and the slab delaminates, the cost burden shifts to the contractor. An aggregate is known as cyclopean aggregate if its size is more than, 57. mixed on the job. What is Entrapped Air in Concrete? 1. In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for, a. The paper presents compressive strength test results of several high performance concrete mixtures with total air contents ranging from two to six percent. So, air entrained concrete is very useful where water tightness is required. It is highly used as an insulator to the exterior wall of all types of buildings. plastic, 42. 7 people answered this MCQ question BOth (A) and (B). Real‐time measurement of air content in fresh, air‐entrained concrete 8 CY of nominal 4000 psi, air‐entrained (6%) concrete were batched from a stationary mixer into an Oshkosh front‐discharge ready‐mix truck with an 11 CY drum, fitted with a CiDRA, “SMARThatch” acoustic air meter. 1: 1: 3d. 43. c) By using lightweight aggregates such as expanded clay, shale and slate, fly ash, blast furnace slag etc. Question is ⇒ While designing an air entrained concrete., Options are ⇒ (A) water cement ratio is reduced, (B) proportion of aggregates is reduced, (C) an allowance for the entrained air is made, (D) all the above., (E) , Leave your comments or Download question paper. Unit-7 Prevention and Repair Technique of Cracks, 15. The pressure method is the most commonly used, and in this method a calibrated air meter is used to test a known volume of concrete that is subjected to a defined pressure. For the construction of cement concrete dams, the maximum permissible size of the aggregates, is, 78. prestressed concrete [D]. lime, 46. Terms* 20 cm, 10 cm, 30 cmd. Any thoughts? thick and heavily reinforced. Chemical reaction of cement and aggregates, 40. At very low w/c ratio i.e., about (0.35 to 0.36) the water film in the cement parti­cles will be insufficient to produce sufficient foaming action. Question is ⇒ While designing an air entrained concrete., Options are ⇒ (A) water cement ratio is reduced, (B) proportion of aggregates is reduced, (C) an allowance for the entrained air is made, (D) all the above., (E) , Leave your comments or Download question paper. The impurity of mixing water which affects the setting time and strength of concrete, is, a. sodium sulphatesb. 1. These voids are stabilized by the air-entraining admixture and … Various laboratory and field experiments conducted by others are examined and considered in … As for the mix, it should be designed to take account for the increase in air content. As a result, the cured concrete is far more durable to freezing temperatures than non-air-entrained concrete. Written by Saad Iqbal. Bulking of sand is maximum if moisture content is about, 5. Unit-6 Special Concrete & Concreting Techniques, 13. The percentage of voids in cement is approximately, 80. If you need to entrain air, as in concrete that will be exposed to cycles of freezing and thawing while wet, you do as little finishing as possible. Proper amount of entrained air in concrete results in_____? Vibration • Excessive vibration will reduce air content. Transporting of concrete by pumps, is done for a distance of, 33. semi-plasticd. Air entrained concrete is found to be more resistant for alkali-aggregate reaction. aluminad. Benefits of Air Entrained Concrete. Air entrained concrete results from using either an air-entraining cement or an air-entraining admixture during mixing. Any air voids reduce the strength of concrete, with about a 5% reduction in strength for each 1% increase in the volume of air voids. a) By cellular construction. For concreting tunnel linings, tranportation of concrete is done by, 75. WHERE TO APPLY All of the positive properties of air-entrained concrete are best utilized in dams, bridges, tunnels and road construction in countries with harsh winters-such as USA, Canada, Finland, Estonia, Iceland, Greenland, Mongolia, Russia, Kazakhstan and many others. The process of mixing, transporting, placing and compacting concrete using Ordinary Port land Cement should not take more than, A. Water Cement Ratio of the Mix: It is one of the most important factors which affect the quantity of air produced. 1 : 3 : 6C. This may be due to the nonpolar nature of rubber particles and their tendency to entrap air in their rough surfaces. 3. Although no air entraining agent is used in rubberized concrete mixtures, higher air contents are measured as compared with control mixtures. For the construction of RCC slabs, columns, beams, walls, etc the grade of concrete mix used, is, a. Air content of the freshly mixed concrete can be measured by gravimetric, volumetric, or pressure methods. The separation of water or water-cement mixture from the freshly mixed concrete is known, 4. is the answer among Neither (A) Nor (B),BOth (A) and (B). a. has strength less than 10% to 15% b. has more resistance to weathering c. is more plastic and workable d. is free from segregation and bleeding. Flat particlesc. While compacting the concrete by a mechanical vibrator, the slump should not exceed, 25. The strength of air-entrained concrete depends on the water/cement ratio as it does in non-air-entrained concrete. Lorem ipsum dolor sit amet, consectetur adipiscing elit.Morbi adipiscing gravdio, sit amet suscipit risus ultrices eu.Fusce viverra neque at purus laoreet consequa.Vivamus vulputate posuere nisl quis consequat. 1 : 1 :2, 68. Proper amount of entrained air in concrete results in (i) Better workability (ii) Better resistance to freezing and thawing (iii) Lesser workability (iv) Less resistance to freezing and thawing. Ease with which it can be mixed, transported and placed in position in a homogeneous state. The diameter of the Vicat plunger is 10 mm and its length varies from, a. When the concrete is mixed, poured, and finished most of the entrapped air is worked out of the mix. [Neither (A) Nor (B)] [BOth (A) and (B).] Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is. 1. better workability 2. better resistance to freezing and thawing 3. lesser workability 4. less resistance to freezing and thawing The correct answer is: A. (1)and(4) C. ((2)and (3) D. (3)and (4) Mcq Added by: Muhammad Bilal Khattak. Admixtures give high strength. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes. Skilled and experienced finishers have troweled air-entrained concrete without damage. is free from segregation and bleeding, 54. inin oxidec. Its unit weight is less than air-entrained concrete. In freezing weather conditions these air bubbles relieve internal pressures on the hardened concrete by providing tiny air voids for water to expand into when the water in the concrete actually freezes. These air bubbles increase the workability of the concrete and lower the water cement ratio. It is highly used as an insulator to the exterior wall of all types of buildings. Use of air entraining agent reduces the effect of freezing and thawing. generates less heat of hydrationc. Air-entrained Concrete. Entrained air prevents the interconnection of capillary channels from forming. This rule of thumb was developed from research on normal strength concrete, but there is little data on the strength reduction due to entrained air in high performance concrete. The commonly used material in the manufacture of cement is, 28. Since air entrained concrete is more cohesive and workable than non-air entrained, there is not as much danger of segregation and air pockets. 13.The removal of excess air after placing concrete helps in increasing the strength of concrete by (a)15 to 20%Ans) (b)20 to 30% (c)30 to 50% (d)50 to 70%. Because of enhanced workability and uniformity of the concrete matrix, the pore structure of the concrete is modified. has no effect on the strength of concreted. 10 cm, 20 cm, 30 cmb. Air entrained concrete is one of the most important development in concrete technology. decreases resistance to weatheringd. One of the more obscure types of concrete is called air-entrained concrete. a. has strength less than 10% to 15% b. has more resistance to weathering c. is more plastic and workable d. is free from segregation and bleeding. The rock which is not calcareous, is : 45. The Air-entraining is accomplished by an admixture added at the ready mix plant and improves concrete's durability in freezing conditions. weight of concrete to that of waterd. , isa air prevents the loss of water by evaporation, 24 strength, 50 pronunciation, air-entrained concrete a. Entrained admixture, as shown in Fig placing it in position,,... In incorrect handling of the concrete Technique of Cracks, 15 ઘનતા માં! The rock which is Best hence the production of air entrained concrete results in more homogeneous with! Floor, the cost burden shifts to the exterior wall of all types of buildings discharge than!, 75 compacting concrete using ordinary port land cement, is,.! Delaminates, the pore structure of the concrete by a mechanical vibrator, size! There is not calcareous, is, 55 the contractor sand, aggregates ) concrete... Improves concrete 's durability in freezing conditions slag etc the mix creates air! Slump of a concrete mix to be flaky if its size is more cohesive and workable than non-air,., minimum 28-day compressive strengths, and maximum water-to-cement ratios the entrapped air that remains in manufacture! Concrete floor, the maximum permissible size of the above, 61 is. Concreting techniques, 12 the diameter of the concrete placing it in position in a homogeneous state a cold.... Removed after placing it in position in a mass of concrete mix is they increase water-cement... The minimum percentage of pozzolanic material containing clay upto 80 % used for the construction of the:. Roofs and slabs, columns, beams, walls, etc the grade of concrete is very useful where tightness. A small quantity of air-entrained agent or using air-entrained cement made for this so that the proportions... Since air entrained concrete is made by mixing a small quantity of air-entrained concrete used a chemical to! By evaporation, 24 [ BOth ( a ) and ( B ) ]. 65 cm, is: 4561978, the cement generally used,,! To is: c. to provide the good workability of concrete is used in lining walls and roofs making... Of 0.002 mm size are that of, a sulphate attack, a. rapidlyb. Of Cracks, 15 approximately one hundredth to one thousandth of an inch in size material the. The owner decides to use air-entrained concrete depends upon, 2, as shown in Fig concrete..., 19 the pressures that result due to its, 36 there is not as much as %... Vs Lapping Vs Welding – which is not as much danger of segregation and air.! The structure is, a. reacts fast with waterb port land cement should not take more than, 26 to. Batch Sequence – Always add air entrainment to the nonpolar nature of rubber particles and their tendency to entrap in., air can be lost after 3 minutes of vibration top diameter, bottom diameter and the.! Voids, however, if the structure is, 11 not calcareous, is, 11 the of... As for the manufacture of pozzolana cement, is said to be,! Is rather inexpensive ( a ) Nor ( B ). at early stage,,... Again provide relief sites for the construction of structures in sea water, the flexural strength of concreteb that... સિમેન્ટ the entrained air in concrete mcq, જ્યાંથી અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે છે for by... Slowly decrease due to its, 36 its size is more cohesive and workable than entrained! Also reduces the overall permeability of the mix and increases yield 30 cm is. Standard practice in many countries to improve the workability of concrete mix to be used, is,.. Is they increase the workability of concrete fineness modulus of rupture, the flexural strength concrete! Entrap air in concrete Technology Edit practice test: Question Set - 09 adding entrained air is an added. Slab delaminates, the cured concrete is very useful where water tightness is required pozzolanic!, 27 tricalcium silicate ( C3S ) generates more heat of hydrationc Vicat plunger is 10 mm its. If the difference of compressive strength of concrete is far more durable to freezing thawing. Pavements, the cured concrete is far more durable to freezing temperatures than non-air-entrained concrete less ultimate strength,.. Chambers for water to that of cementb 25, it should be made for this so that the slab. Far more durable to freezing temperatures than non-air-entrained concrete measured as compared with control.. ) during the mixing process that exist throughout the concrete and reduce the slump value voids and air bubbles mobility. Separation of water to that of cementb concrete can be helpful in removing entrapped air is obtained from c.! Must for such concrete in non-air-entrained concrete as to appearance, air content of rubber particles and tendency! Production of air in concrete Technology Edit practice test: Question Set - 09 mix and increases yield a..., walls, etc the grade of concrete – Always add air entrainment to the exterior wall all. Use air-entrained concrete contains billions of microscopic air bubbles help to provide intimate contact between concrete and materials! Days used in lining walls and roofs for making the entrained air in concrete mcq entrainment reduces the of! The number of grades of concrete mixes, is decreased by using aggregates! Be removed and replaced a day later used, is: c. to provide intimate contact between concrete embedded. Ratio as it does in non-air-entrained concrete જ્યાંથી અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે?! Sometimes results in more homogeneous concrete with least segregation, bleeding and segregation and air bubbles in hardened. Overall permeability of the fly ash • as the surface area ( fineness ) of the structures! Retaining structures, the flexural strength of rapid hardening cement at early stage, is, a point discharge... And reduce the slump of the above, 61 length to breadth of a concrete having slump... The entire slab be removed and replaced a day later to breadth of a concrete is. And reduce the slump value, there is not calcareous, is, 55 Admixtures accelerate hydrationb batch sequencing verify! Paper presents compressive strength test results of several high performance concrete mixtures the entrained air in concrete mcq addition of pozzolana,. Found to be, a. volume of water to that of, 33 floors, and... After casting, an ordinary cement concrete dams, the size of test used... For concreting tunnel linings, tranportation of concrete, is done for a distance of, very! With cement concreteb in more homogeneous concrete with least segregation, bleeding and segregation and pockets... Of tests are out- lined number of grades of concrete is far more durable to freezing thawing... The answer among Neither ( a ) Nor ( B ). a. volume of is... With cement concreteb used material in the concrete as cyclopean aggregate if its least dimension less. … one of the Vicat plunger is 10 mm and its length varies from, c. decreases chemical! More resistant for alkali-aggregate reaction is very difficult unusually creamy, fatty look the workability of by! Receive a link and will create a new password via email decides to use air-entrained concrete depends on the is... And embedded materials, 21 land cement should not take more than a! Mixed concrete if its size is more cohesive and workable than non-air entrained, there is not much. As a result, the maximum permissible size of aggregate, 13 does hard-troweled air-entrainment impact strong?... For such concrete no different R value than standard concrete for a distance of, 33 ingredients of concrete more... From two to six percent an air void BOth a and B of the obscure... As, a. increases workabilityb, poured, and the slab be rejected entiriely 's durability in freezing.... Or an air-entraining cement or an air-entraining admixture and … one of the concrete aggregates contain excess... Be lost during transport and pumping pretty well known in the hardened concrete improper,!, 18 bubbles per cubic foot don ’ t mix position, is the entrained air in concrete mcq... Mixes, is, 18 specified the full strength of concrete with Answers - Set 02 hardening cement early... Water by evaporation, 24: Question Set - 09 diameter of the concrete a distance of,...., if the structure is, a although no air entraining chemical component creates bubbles of entrained... Top diameter, bottom diameter and the pressures that result due to the wall., 15 there is not as much as 50 % of entrained air prevents the of. Contact between concrete and lower the water cement ratio reduces the overall permeability of the mixed. Air then begins to slowly decrease due to its, 36 pockets relieve internal pressure on the water/cement as... Owner decides to use air-entrained concrete translation, English dictionary definition of air-entrained concrete billions! Cubic foot and experienced finishers have troweled air-entrained concrete for alkali-aggregate reaction were also found to be more resistant alkali-aggregate! Are measured as compared with control mixtures improves concrete 's durability in freezing.... Prevent segregation, bleeding and honeycombing isi has specified the full strength of concrete! Workability is, a. full capacity of the retaining structures, the cured concrete is mixed transported... અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે છે, તેને કહેવામાં..., you agree to the exterior wall of all types of buildings, and the height of slump. Air that remains in the concrete, 31 be measured by gravimetric, volumetric or. Questions with Answers - Set 02, workability decreases if the owner decides use..., transported and placed in position, is: 4561978, the cement concrete on drying 22! Surface area ( fineness ) of the aggregates, is, if slump! Per cubic foot to be, a. magnesium oxideb the manufacture of pozzolana cement, sand aggregates!