The basic purpose of a retarder in concrete is
(A) To increase the initial setting time of cement paste in concrete
(B) To decrease the initial setting time of cement paste in concrete
(C) To render the concrete more water tight
(D) To improve the workability of concrete mix

1 Answer

Answer :

Answer: Option A

Related questions

Description : Pick up the correct statement from the following: (A) An increase in water content must be accompanied by an increase in cement content (B) Angular and rough aggregates reduce the workability of the ... The slump of the concrete mix decreases due to an increase in temperature (D) All the above

Last Answer : Answer: Option D

Description : Workability of concrete is inversely proportional to (A) Time of transit (B) water-cement ratio (C) The air in the mix (D) Size of aggregate

Last Answer : Answer: Option A

Description : Workability of concrete mix with low water cement ratio is determined by (A) Tensile strength test (B) Slump test (C) Compaction factor test (D) Flexural strength test

Last Answer : Answer: Option C

Description : Workability of concrete mix with low water cement ratio is determined by [ A ] Tensile strength test [ B ] Slump cone test [ C ] Compaction factor test [ D ] Flexural strength test

Last Answer : [ C ] Compaction factor test

Description : Pick up the incorrect statement from the following. While performing preliminary test on concrete (A) Proportions of the material and water should be the same as to be used at the work site (B) ... in air-tight containers (D) Concrete ingredients should be kept at a temperature of 37° 2°C

Last Answer : Answer: Option D

Description : Pick up the correct statement from the following: (A) Higher workability indicates unexpected increase in the moisture content (B) Higher workability indicates deficiency of sand (C) If the concrete mix is dry, the slump is zero (D) All the above

Last Answer : Answer: Option D

Description : Increase in water content in a cement concrete (i) Increases workability (ii) Increases the strength [ A ] i [ B ] ii [ C ] both (i) and (ii) [ D ] neither (i) nor (ii)

Last Answer : [ A ] i

Description : While determining the workability of concrete mix, the compaction factor test is ------than the slump cone test [ A ] Less accurate [ B ] More accurate [ C ] Approximate method [ D ] None of the above

Last Answer : [ B ] More accurate

Description : If the slump of a concrete mix is 60 mm, its workability is (A) Very low (B) Low (C) Medium (D) High

Last Answer : Answer: Option C

Description : Pick up the correct statement from the following: (A) Segregation is necessary for a workable concrete (B) Consistency does not affect the workability of concrete (C) If the concrete mix is dry, the slump is maximum (D) None of these

Last Answer : Answer: Option D

Description : Workability of a concrete – mix is determined by (i)Slump cone test (ii)Compaction factor test (iii)Vee bee test [ A ] i [ B ] ii [ C ] i and ii [ D ] i, ii and iii

Last Answer : [ D ] i, ii and iii

Description : If the slump of a concrete mix is 50 to 100 mm, its workability is [ A ] Very low [ B ] Low [ C ] Medium [ D ] High

Last Answer : [ C ] Medium

Description : Slump cone test is used to determine [ A ] Shrinkage of concrete mix [ B ] Creep of concrete [ C ] Workability of concrete mix [ D ] Soundness of concrete

Last Answer : [ C ] Workability of concrete mix

Description : Pick up the correct statement from the following: (A) Water enables chemical reaction to take place with cement (B) Water lubricates the mixture of gravel, sand and cement (C) Strength of concrete structure largely depends upon its workability (D) All the above

Last Answer : (D) All the above

Description : C.R.R.I. charts are used to obtain a relationship between strength of concrete and (A) Water cement ratio (B) Workability (C) Grading of aggregate (D) Fineness modulus

Last Answer : Answer: Option A

Description : The workability of concrete is expressed by (a) Water-cement ratio (b) Slump value (c) Compaction factor (d) Both (a) and (b)

Last Answer : (d) Both (a) and (b)

Description : The workability of concrete is mostly influenced by its [ A ] Water cement ratio [ B ] Aggregate cement ratio [ C ] Cement content [ D ] Water content

Last Answer : [ A ] Water cement ratio

Description : The separation of water or water cement mixture from the freshly laid concrete is known as [ A ] Workability [ B ] Segregation [ C ] Bleeding [ D ] Creep

Last Answer : [ C ] Bleeding

Description : Admixtures which cause early setting and hardening of concrete are called (A) Workability admixtures (B) Accelerators (C) Retarders (D) Air entraining agents

Last Answer : Answer: Option B

Description : Workability of concrete is directly proportional to (A) Aggregate cement ratio (B) Time of transit (C) Grading of the aggregate (D) All of above

Last Answer : Answer: Option C

Description : Higher workability of concrete is required if the structure is (A) Made with cement concrete (B) Thick and reinforced (C) Thin and heavily reinforced (D) Thick and heavily reinforced

Last Answer : Answer: Option D

Description : Pick up the incorrect statement from the following: (A) The degree of grinding of cement, is called fineness (B) The process of changing cement paste into hard mass, is known as setting of ... (D) The heat generated during chemical reaction of cement with water, is known as heat of hydration

Last Answer : Answer: Option C

Description : The most commonly used retarder in cement is (A) Gypsum (B) Calcium chloride (C) Calcium carbonate (D) None of the above

Last Answer : Answer: Option A

Description : Pick up the correct statement from the following: (A) Water cement paste hardens due to hydration (B) During hardening cement binds the aggregates together (C) Cement provides strength, durability and water tightness to the concrete (D) All the above

Last Answer : Answer: Option D

Description : When each particle of aggregates is thinly coated with cement paste, a heterogeneous solid is formed, which is known as (A) Hydration (B) Gel (C) Concrete (D) None of these

Last Answer : Answer: Option C

Description : Strength of concrete increases with (A) Increase in water-cement ratio (B) Increase in fineness of cement (C) Decrease in curing time (D) Decrease in size of aggregate

Last Answer : (B) Increase in fineness of cement

Description : The effect of adding calcium chloride in concrete is (i) To increase shrinkage (ii) To decrease shrinkage (iii) To increase setting time (iv) To decrease setting time The correct answer is (A) (i) and (iii) (B) (i) and (iv) (C) (ii) and (iii) (D) (ii) and (iv)

Last Answer : (B) (i) and (iv)

Description : The strength of cement concrete increases with (a) The increase of water cement ratio. (b) The decrease of water cement ratio. (c) The increase of cement ratio (d) None of these

Last Answer : (a) The increase of water cement ratio.

Description : If ‘W’ is the percentage of water required for normal consistency of cement, water to be added for determination of initial setting time is (a) 0.50 W (b) 0.62 W (c) 0.75 W (d) 0.85 W

Last Answer : (d) 0.85 W

Description : Tricalcium aluminate (C3A) (A) Reacts fast with water (B) Generates less heat of hydration (C) Causes initial setting and early strength of cement (D) Does not contribute to develop ultimate strength

Last Answer : Answer: Option B

Description : For an ordinary Portland cement (A) Residual does not exceed 10% when sieved through IS Sieve No. 9 (B) Soundness varies from 5 to 10 mm (C) Initial setting time is not less than 30 minutes (D) Compressive stress after 7 days, is not less than 175 kg/cm2

Last Answer : (C) Initial setting time is not less than 30 minutes

Description : As compared to ordinary Portland cement, high alumina cement has (A) Higher initial setting time but lower final setting time (B) Lower initial setting time but higher final setting time (C) Higher initial and final setting times (D) Lower initial and final setting times

Last Answer : Answer: Option A

Description : Pick up the correct statement regarding low heat cement from the following: (A) It possesses less compressive strength (B) Its initial setting time is about one hour (C) Its final setting time is about 10 hours (D) All the above

Last Answer : Answer: Option D

Description : To retard the initial setting time of cement, the compound responsible, is (A) Tri-calcium silicate (B) Gypsum (C) Di-calcium silicate (D) Tri-calcium aluminate

Last Answer : Answer: Option B

Description : Initial setting time of cement for asbestos cement products should be not less than (A) 30 minutes (B) 50 minutes (C) 75 minutes (D) 90 minutes

Last Answer : Answer: Option D

Description : The initial setting time for ordinary Portland cement as per IS specifications should not be less than (A) 10 minutes (B) 30 minutes (C) 60 minutes (D) 600 minutes

Last Answer : Answer: Option B

Description : According to IS Code , the requirement of an ordinary Portland cement is (a) The residue does not exceed 10% when sieved through is sieve no .9 (b) Its initial setting time is not less than 30 minutes. (c) its expansion is not morethan 10mm for unaerated cement (d) All the above.

Last Answer : (d) All the above.

Description : The gypsum is added to the cement for (a) Providing high strength to the cement (b) Controlling the initial setting time of cement. (c) Lowering the clinkering temp of cement (d) All the above.

Last Answer : (b) Controlling the initial setting time of cement.

Description : The obturating material of choice for primary teeth following complete pulpectomy is, A. Zn phosphate cement and formcresol combination paste B. Quick setting hydroxide cement C. Zinc oxide and eugenol cement D. Gutta-percha E. Polycarboxylate cement

Last Answer : C. Zinc oxide and eugenol cement

Description : Initial setting of cement is caused due to (A) Tri-calcium silicate (B) Di-calcium silicate (C) Tri-calcium aluminate (D) Tetra calcium alumino ferrite

Last Answer : Answer: Option C

Description : Soundness test of cement determines (A) Quality of free lime (B) Ultimate strength (C) Durability (D) Initial setting

Last Answer : Answer: Option A

Description : The main constituent of cement which is responsible for initial setting of cement is (A) Di-calcium silicate (B) Tri-calcium silicate (C) Tri-calcium aluminate (D) All of the above

Last Answer : Answer: Option C

Description : A thick paste of cement, sand and water is called – (1) Concrete (2) R.C.C. (3) Mortar (4) Kiln

Last Answer : (3) Mortar Explanation: Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water

Description : A thick paste of cement, sand and water is called (1) Concrete (2) R.C.C. (3) Mortar (4) Kiln

Last Answer : Mortar

Description : The shrinkage of concrete (A) Is proportional to water content is the mix (B) Is proportional to cement concrete (C) Increases with age of concrete (D) All the above

Last Answer : (D) All the above

Description : Pick up the correct statement from the following: (A) The weight of ingredients of concrete mix, is taken in kilograms (B) Water and aggregates are measured in litres (C) 20 bags of cement make one tonne (D) All the above

Last Answer : Answer: Option D

Description : According to Water-Cement Ratio Law, the strength of workable plastic concrete (A) Depends upon the amount of water used in the mix (B) Does not depend upon the quality of cement mixed with aggregates (C) Does not depend upon the quantity of cement mixed with aggregates (D) All the above

Last Answer : Answer: Option D

Description : If 50 kg of fine aggregates and 100 kg of coarse aggregates are mixed in a concrete whose water cement ratio is 0.6, the weight of water required for harsh mix, is (A) 8 kg (B) 10 kg (C) 12 kg (D) 14 kg

Last Answer : Answer: Option C

Description : Inert material of a cement concrete mix, is (A) Water (B) Cement (C) Aggregate (D) None of these

Last Answer : Answer: Option C

Description : Shrinkage in concrete can be reduced by using (A) Low water cement ratio (B) Less cement in the concrete (C) Proper concrete mix (D) All the above

Last Answer : Answer: Option D