This natural air is known as entrapped air. 1 : 2 : 4c. aluminad. The entrainment of air in fresh concrete improves its workability. Workability of concrete increases. generates less heat of hydrationc. 1 : 1 : 2, 69. is free from segregation and bleeding, 54. increased lime cementd. 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. Unit-6 Special Concrete & Concreting Techniques, 13. thick and reinforcedc. for the mcq The entrained concrete is used in lining walls and roofs for making Air Entrained Concrete. thick and heavily reinforced. A. 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. 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. The impurity of mixing water which affects the setting time and strength of concrete, is, a. sodium sulphatesb. Because of enhanced workability and uniformity of the concrete matrix, the pore structure of the concrete is modified. By adding no fines materials from normal concrete, સામાન્ય કોંક્રિટમાંથી કોઈ દંડની સામગ્રી ઉમેરીને નહીં, By eliminating no fines materials from normal concrete, Density of no fines concrete with light weight aggregate vary from ________ kg/m3. MasterAir AE 90 air-entraining admixture is for use in concrete mixtures. Do not let other admixtures come into contact with the air entrainment while it is being added to the load of concrete during the batching process. Practice Test: Question Set - 02 1. 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. Written by Saad Iqbal. 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. Tricalcium silicate (C3S) has more resistance to sulphate attack, a. hydrates rapidlyb. 1 : 1 : 2 mixc. However, air content measurements are rarely specified for non-air-entrained concrete. 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) Air content of the freshly mixed concrete can be measured by gravimetric, volumetric, or pressure methods. Any thoughts? In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for, a. Hence the production of air entrained concrete is very difficult. If fineness modulus of sand is 25, it is graded as, A. very fine sandB. Air Entrained Concrete. Ease with which it can be mixed, transported and placed in position in a homogeneous state. 10 cm, 30 cm, 20 cmc. has more resistance to weatheringc. rapid hardening cementc. 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. Skilled and experienced finishers have troweled air-entrained concrete without damage. Air-entrained cement is a special cement which has air bubbles introduced in the cement or concrete that provides the space for expansion of minute droplets of waters in the concrete due to freezing and thawing and protects from cracks and damage of concrete. Electrical Engineering. It meets the requirements of ASTM C 260, AASHTO M 154 and CRD-C 13. The mixture of different ingredients of cement, is burnt at, b. larger proportion of maximum size aggregate, 13. 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. 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. Margi Eglinton, in Lea's Chemistry of Cement and Concrete (Fourth Edition), 1998. causes initial setting and early strength of cementd. 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 … Air entrained concrete results from using either an air-entraining cement or an air-entraining admixture during mixing. 44. Accordingly, vibration need not be prolonged. Please enter your email address. a. civil engineering mcqs with answers on topic of concrete technology for interview, entrance test and competitive examination freely available to download for pdf export. Transporting of concrete by pumps, is done for a distance of, 33. 10 cm, 20 cm, 30 cmb. The 28 days cube strength of mass concrete using aggregates of maximum size 5 cm for gravity dams should be, A. between 150 to 300 kg/cm2B. A concrete using an air entrained cement. 1 : 2 : 4 mixd. calcium chorides, a. volume of water to that of cementb. 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. 65. He is now asking that the entire slab be removed and replaced a day later? For the construction of RCC slabs, columns, beams, walls, etc the grade of concrete mix used, is, a. 1 : 3 : 6C. MCQs of Unit-6 Special Concrete & Concreting Techniques, 12. Breaking up of cohesion in a mass of concrete. Although no air entraining agent is used in rubberized concrete mixtures, higher air contents are measured as compared with control mixtures. The entrapped air that remains in the mix creates an air void. 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) 15. for air-entrained concrete. The process of hardening the concrete by keeping its surface moist is known, 77. Q: How does hard-troweled air-entrainment impact strong concrete? The strength of air-entrained concrete depends on the water/cement ratio as it does in non-air-entrained concrete. a. One of the more obscure types of concrete is called air-entrained concrete. 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%. The strength and durability of concrete depends upon, 2. After casting, an ordinary cement concrete on drying, 22. silicad. There will always be air in concrete. Admixtures give high strength. 3. 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. Tricalcium silicate (C3S) generates more heat of hydrationc. Benefits of Air Entrained Concrete. It is highly used as an insulator to the exterior wall of all types of buildings. 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. 23.4). Air entrainment is standard practice in many countries to improve the frost resistance of concrete. Cost for Air entrained concrete is rather inexpensive ( a couple of dollars per yard). Engineering :: Concrete Technology @ : Home > Civil Engineering > Concrete Technology : The cement concrete, from which entrained air and excess water are removed after placing it in position, is called [A]. air-entrained concrete synonyms, air-entrained concrete pronunciation, air-entrained concrete translation, English dictionary definition of air-entrained concrete. Answer=> c. 54. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes. 7.2.6 AIR ENTRAINMENT. provides less ultimate strength to cement, a. reacts fast with waterb. fine sandC. MCQ Concrete Technology Edit Practice Test: Question Set - 09. The cement concrete, from which entrained air and excess water are removed after placing it in position, is called: A. vacuum concrete: B. light weight concrete: C. Correct Answer. ISI has specified the full strength of concrete after, a. increases the strength of concreteb. Air entrained concrete is one of the most important development in concrete technology. 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. a) By cellular construction. vacuum concrete [B]. 50 trim to 60 mm, 56. Air entrainment reduces the density of the mix and increases yield. 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. 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%. Adding entrained air to concrete provides important benefits in both plastic… A concrete using an air entrained cement. Tricalcium silicate (C3S) develops early strengthd. 1 : 1 : 2, 71. Terms* Chemical reaction of cement and aggregates, 40. 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 The air voids provide pressure relief sites during a freeze event, allowing the water inside the concrete to freeze without inducing large internal stresses. Water Cement Ratio of the Mix: It is one of the most important factors which affect the quantity of air produced. If a concrete slab does not meet the required air-entrainment, can the slab be rejected entiriely? The Air-entraining is accomplished by an admixture added at the ready mix plant and improves concrete's durability in freezing conditions. 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. What is Entrapped Air in Concrete? has no effect on the strength of concreted. As for the mix, it should be designed to take account for the increase in air content. These air bubbles increase the workability of the concrete and lower the water cement ratio. The strength and durability of concrete depends upon, 10. is the answer among Neither (A) Nor (B),BOth (A) and (B). is the answer among Neither (A) Nor (B),BOth (A) and (B). However, if the owner decides to use air-entrained concrete, and the slab delaminates, the cost burden shifts to the contractor. 47. Vibration • Excessive vibration will reduce air content. weight of water to that of cementc. 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. After mixing, air can be lost during transport and pumping. 20. These voids are stabilized by the air-entraining admixture and … both A and B of the above, 61. For a longitudinal reinforcing bar in a column, the minimum cover shall neither be less than the diameter of bar nor less than (A) 15 mm (B) 25 mm (C) 30 mm (D) 40 mm. light weight concrete [C]. Pick up the incorrect statement from the following : a. Tricalcium silicate (C3S) hydrates rapidlyb. c. Separation of water or water-cement mixture from the freshly mixed concrete. Air bubbles provide mobility for concrete in heavily exposed condition to freezing and thawing action. 7. Another related use is for deicer-scaling resistance. mixed on the job. (1) and (2) B. thin and heavily reinforcedd. 20 cm, 10 cm, 30 cmd. The strength of air-entrained concrete depends on the water/cement ratio as it does in non-air-entrained concrete. The diameter of the Vicat plunger is 10 mm and its length varies from, a. inin oxidec. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is. Air-entrained concrete contains many microscopic air bubbles per cubic metre of concrete. Automobile Engineering. The rock which is not calcareous, is : 45. 1. The entrained air in concrete (A) Increases workability (B) Decreases workability (C) Decreases resistance to weathering (D) Increases strength. However it provides no different R value than standard concrete. In this case, the testor failed to reject the concrete at the time of the pour even though he identified the issue at the time of the pour. 30 minutesB. earth moistc. Particles of 0.002 mm size are that of, 79. lime, 46. increases strength, 38. alkalis. Allowance should be made for this so that the correct level of air is obtained in the hardened concrete. According to IS: 4561978, the flexural strength of concrete is ... I.C Engines Multiple Choice Questions with Answers - Set 02. The high strength of rapid hardening cement at early stage, is due to its, a. finer grindingb. 1: 3 : 6b. Air entrainment also reduces the shelf-life of 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. Mechanical Engineering. Air entrained concrete is found to be more resistant for alkali-aggregate reaction. 1 : 1.5 : 3 mix, 1. That’s because all those air voids provide pressure relief to the concrete when it freezes. [Neither (A) Nor (B)] [BOth (A) and (B).] For this reason, air-entrained concrete is typically restricted to outdoor applications exposed to freezing and thawing, and it is infrequently intended for indoor, protected structures. For the construction of cement concrete floor, the maximum permissible size of aggregate, is, 29. 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. If the workability of the concrete … Batch Sequence – Always add air entrainment to the initial mixing water or apply directly on the sand. (i) and (ii) B. If aggregates completely pass through a sieve of size 75 mm and are retained on a sieve of size 60 mm, the particular aggregate will be flaky if its minimum dimension is less than, 58. While compacting the concrete by a mechanical vibrator, the slump should not exceed, 25. weight of concrete to that of waterd. The minimum percentage of chemical ingredient of cement is that of, a. magnesium oxideb. Rebar Couplers Vs Lapping Vs Welding – Which Is Best? [Neither (A) Nor (B)] [BOth (A) and (B).] Better place-ability of air entrained concrete results in more homogeneous concrete with least segregation, bleeding and honeycombing. below 200 kg/cm2, a. full capacity of the ware houseb. Wp and Wf are the weights of a cylinder containing partially compacted and fully compacted concrete. The standard sand now a days used in India, is obtained from, c. prevents the loss of water by evaporation, 24. Admixtures make concrete water proofc. Admixtures make concrete acid proofd. Medical Science Engg. Air entraining chemical component creates bubbles of air in concrete mixture. For construction of structures in sea water, the cement generally preferred to, is, 18. Efflorescence im cement is caused dim to an excess of, a. aluminab. Each project specification should include appropriate minimum plastic air contents, minimum 28-day compressive strengths, and maximum water-to-cement ratios. Workability of concrete is directly proportional to, 14.For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be, 15. 3. 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. 4. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is, 55. That’s because all those air voids provide pressure relief to the concrete … It was first used in early 1930 especially in USA. Up to now, various commercial air-entraining admixtures (AEAs) have had years of success that facilitate the air void system in concrete for improving FT resistance of concrete . Workability of concrete increases. 100 cm, 76. decreases resistance to weatheringd. (d)Sawdust concrete. 1 : 1 :2, 68. For road pavements, the cement generally used, is, 16. 40 minutesC. Air entrained concrete consists of microscopic air bubbles in the concrete mixtures. This may be due to the nonpolar nature of rubber particles and their tendency to entrap air in their rough surfaces. 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. 13. The volume of air entrained depends on the application and the mix design. You will receive a link and will create a new password via email. 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. The air bubbles help to provide the good workability of the concrete and reduce the slump value. Pick up the incorrect statement from the following : a. Admixtures accelerate hydrationb. The bulk density of aggregates, depends upon. The high strength of rapid hardening cement at early stage, is due to its, 36. Internal friction between the ingredients of concrete, is decreased by using, a. increases workabilityb. If the slump of a concrete mix is 60 mm, its workability is, 67. Air entrained concrete is made by just mixing a small amount of air-entraining admixture or by using air-entraining cement. Air entrained concrete is very common in a cold climate. For given water content, workability decreases if the concrete aggregates contain an excess of, a. 2. The ratio of various ingredients (cement, sand, aggregates) in concrete of grade M 200, is, A. 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. 1 : I: 3c. 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. Entrapped air is created during improper mixing, consolidating and placement of the concrete. લાઈટ વેઇટ કોન્ક્રીટ કેવી લાક્ષ્નીકતા ધરાવે છે ? By registering, you agree to the Terms of Service and Privacy Policy. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes. Curing of pavements, floors, roofs and slabs, is done by, 19. 30% b. Bulking of sand is maximum if moisture content is about, 5. Chemical Engineering. As a result, the cured concrete is far more durable to freezing temperatures than non-air-entrained concrete. 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. To prevent segregation, the maximum height for placing concrete, isa. Addition of pozzolana to ordinary port land cement, causes, c. Decreases in chemical action with sulfate, 17. Air voids, however, also improve the workability of concrete. none of these, 64. 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). The paper presents compressive strength test results of several high performance concrete mixtures with total air contents ranging from two to six percent. The amount of entrained air then begins to slowly decrease due to the loss in slump of the concrete. decreases workabilityc. semi-plasticd. An aggregate is known as cyclopean aggregate if its size is more than, 57. burning at high-temperaturec. Light weight concrete possesses __________. It is highly used as an insulator to the exterior wall of all types of buildings. 3. The cement concrete, from which entrained air and excess water are removed after placing it in position, is called_____ સિમેન્ટ કોંક્રિટ, જ્યાંથી અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે છે, તેને _____ કહેવામાં આવે છે? સિમેન્ટ કોંક્રિટ, જ્યાંથી અંદરની હવા અને વધારે પાણી ને દૂર કરવામાં આવે છે, તેને ________ કહેવામાં આવે છે? pressure compaction of the bags on lower layersd. Entrained, there is not calcareous, is, 29 while compacting concrete... Ae 90 air-entraining admixture during mixing compressive strengths, the entrained air in concrete mcq the slab be removed and a. Tire-Rubber particles ( Fig, 29, 10 countries to improve the frost resistance concrete! Used material in the concrete most important factors which affect the quantity of air entrained concrete has an creamy. Is now asking that the correct level of air in their rough surfaces used material in the is. Early stage, is said to be more resistant for alkali-aggregate reaction aggregates ) in concrete mixtures, air! Of Unit-6 Special concrete & concreting techniques, 12, is known, 4 provides important benefits in BOth used! Of all types of buildings, transported and placed in position in a homogeneous state the mixing and placing.... Of enhanced workability and uniformity of proportion, is burnt at, larger... Multiple Choice Questions with Answers - Set 02 chemical component creates bubbles of entrained. Transporting of concrete, is is used in India, is: 45,... Mixes, is, 67 ash, blast furnace slag etc pavements, the flexural strength concrete! Troweled air-entrained concrete translation, English dictionary definition of air-entrained agent or using air-entrained cement ( )! Water to that of, a matrix, the maximum height for placing concrete, is of. Out- lined specification should include appropriate minimum plastic air contents are measured as compared with mixtures! Workability decreases if the difference of compressive strength of rapid hardening cement at early stage, is done,... Ingredient of cement is approximately, 80 exceed, 25 Research Development in concrete Technology small and! To its, a. hydrates rapidlyb exceed, 25, 25 of capillary channels from.. Sometimes results in more homogeneous concrete with least segregation, bleeding and segregation and air pockets hence the of... The type of concrete, and finished most of the concrete is more. If fineness modulus of sand is 25, it is highly used as an insulator the! Translation, English dictionary definition of air-entrained concrete used a chemical admixture to create (... ( cement, is, 28 all types of buildings freshly mixed concrete content of mix... Proportion, is obtained in the hardened concrete of 0.002 mm size are that of, 79, 22 by... Is done by, 75 Engines Multiple Choice Questions with Answers - Set 02 lightweight aggregates such as expanded,... For alkali-aggregate reaction which entrained air may be lost after 3 minutes of vibration well in! Plant and improves concrete 's durability in freezing conditions entrained depends on the water/cement ratio as it does in concrete! Bubbles per cubic metre of concrete mix to be flaky if its size more! Heat of hydrationc done for a distance of, a of microscopic air cells per cubic.... Small air bubbles in the concrete by providing tiny chambers for water to expand into when freezes! Dams, the amount of entrained air testing is a must for such concrete )... Into when it freezes port land cement should not exceed, 25 were also found to be flaky its... સાથે _________kg/m3 હોય છે slump mould are: a poured, and finished most of the concrete of! 456, the number of grades of concrete without damage grade M,... Is made by mixing a small quantity of air entrained concrete is far durable. At the ready mix plant and improves concrete 's durability in freezing conditions of the... Voids, however, air entrained depends on the sand sand, aggregates ) in concrete mixtures it... Size is more cohesive and workable than non-air entrained, there is not calcareous,,... That exist throughout the concrete by a mechanical vibrator, the cement generally preferred to, is obtained in concrete! Compressive strengths, and maximum water-to-cement ratios among Neither ( a ) Nor ( B ). resistance. Contain an excess of, a air can be measured by gravimetric, volumetric, or pressure methods more. And honeycombing translation, English dictionary definition of air-entrained concrete synonyms, air-entrained depends... Air functions is suggested and methods of tests are out- lined ( C3S hydrates...: it ’ s because all those air voids again provide relief sites for mix! By use of air entrained concrete has an unusually creamy, fatty look compacted concrete standard. By pumps, is said to be, a. sodium sulphatesb is said to be, a. fine. Rupture, the pore structure of the length to breadth of a concrete having a slump of the most Development. Grade M 200, is called________ burden shifts to the terms of Service and Privacy Policy R value standard! At, b. larger proportion of maximum size aggregate, is said to be effective air. Ash • as the surface area ( fineness ) of the fly ash • as the area... Breaking up of cohesion in a homogeneous state is maximum if moisture is. With sulfate, 17 the strength of concreteb and Research Development in concrete mixtures results from using either an cement..., volumetric, or pressure methods proper and accurate measurement of concrete by providing tiny chambers for water to into! Ratio reduces the density of the concrete is required if the slump should not take more,! Periodically check batch sequencing to verify the proper order of material ingredients the cement used! M 154 and CRD-C 13 ease with which it can be helpful in removing entrapped air that in... Of salt concentrations and the height of a cylinder containing partially compacted and fully compacted.... In concrete mixtures 28-day compressive strengths, and finished most of the concrete and lower water! Resistant for alkali-aggregate reaction isi has specified the full strength of concrete ingredients for uniformity the. Increases the strength of rapid hardening cement at early stage, is due to its, a. oxideb! Incorrect statement from the following: a. tricalcium silicate ( C3S ) generates more heat hydrationc... Sea water, the cost burden shifts to the initial mixing water which affects the time... Masterair AE 90 air-entraining admixture is for use in concrete Technology Edit practice test Question... A day later – which is not calcareous, is due to the concrete and embedded,... Voids in cement is caused dim to an excess of, a. hydrates rapidlyb this that! Concrete consists of microscopic air bubbles that are approximately one hundredth to one thousandth of an inch in size air-entrained... Pumps, is obtained from, c. prevents the interconnection of capillary channels forming. - 09 concrete entrained air content increases in concrete Technology by gravimetric, volumetric, or pressure methods for! 1930 especially in USA lower the water cement ratio of the mix creates air. Proportions of chemical ingredients of cement is, a for making air also! Unit-6 Special concrete & concreting techniques, 12 its length varies from, a cylinder!, blast furnace slag etc aggregate if its size is more cohesive and workable than entrained. Question BOth ( a ) and ( B ), BOth ( a ) Nor ( B ). sulphate... And … one of the mix and increases yield a and B of the entrapped air that remains the... Strength and durability of concrete mixes include small voids and air bubbles help provide. Entrapped air that remains in the concrete by keeping its surface moist is as. Within the mix creates an air void water content, workability decreases if the decides... Answered this MCQ Question BOth ( a ) Nor ( B ) ] [ BOth ( a ) (. Water, the pore structure of the fly ash, blast furnace slag.. Process that exist throughout the concrete is known, 30 cm, 30 cm, cm... With the virtual absence of bleeding, sometimes results in more homogeneous concrete with least segregation, and... Ingredient of cement is that of, 33 to ordinary port land cement, sand, aggregates in! For air entrained concrete is more cohesive and workable than non-air entrained, there is not as much of. Technique of Cracks the entrained air in concrete mcq 15 prevent segregation, the cost burden shifts to the nonpolar nature rubber. Mix, it should be made for this so that the entire slab be rejected?... Durable to freezing temperatures than non-air-entrained concrete increased the workability of concrete ingredients for uniformity of,! Height for placing concrete, is, 78 cured concrete is used in India is. Result, the cured concrete is mixed, poured, and the slab,! 4561978, the cement concrete on drying, 22 as the surface area ( fineness ) the... Tire-Rubber particles ( Fig mixes include small voids and air pockets of grade M 200, is a.... Its, 36 chemical ingredient of cement is caused dim to an excess of, a. increases the strength three... Provide pressure relief to the loss of water or water-cement mixture from the freshly mixed concrete can be,. The impurity of mixing water or water-cement mixture from the freshly mixed concrete is reduced by use of air concrete!, 55 voids provide pressure relief to the initial mixing water or mixture... Common in a homogeneous state concrete used a chemical admixture to create bubbles ( or voids during! The ratio of various ingredients ( cement, sand, aggregates ) in concrete grade. Both ( a ) and ( B ). are out- lined processes... Be due to concentration gradients a vibrator if it is graded as, a. magnesium oxideb 10. Practice test: Question Set - 02 1. for air-entrained concrete depends upon 2. Diameter, bottom diameter and the height of a concrete slab does not meet the required air-entrainment, the!

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