267.  Consider the following statements regarding hydration of cement : 1 The reaction of cement with water is exothermic 2 The hydration process is not an instantan ions one 3 The hydration reaction is slonier in the early period 4 The hydration reaction is faster in the early period and continues indefinitely at a decreasing rate Of these statements :
A. 1 is correct
B. 2 is correct
C. 1, 2, 3 the correct
D. 1, 2, 4 are corr at

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268.  Consider the following statements regarding' constituents of cement : 1, C3S and C2S on hydration form the same hydrated compound 2 C3S produces comparatively lesser quantity of calcium silicate hydrates as compared to Ca(OH)2 3 Ca(OH)2 is a desirable product in hydralic structures 4 C3S produces more heat of hydration Of the statements :
A. 1 and 2 are correct
B. 2 and 3 are correct
C. 3 and 4 are correct
D. 1, 2, 4 are correct

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269.  Consider the following statements regarding rapid hardening cement 1 Rapid rate of development of strength is due to fineness of grinding, higher C3S content and lower C25 content 2 It produces much greater heat of hydration during to early period 3 It is generally preferred in fore falricated concrete construct 4 This most semitable for road repair works of these statements :
A. statement 1 alone is correct
B. statement 3 alone is correct
C. statement 4 alone is correct
D. statement 1, 2, 3, 4 are correct

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270.  Consider the following statements regarding the size of aggregate : 1- When the size of aggregate is bigger than 4?75 mm, it is called coarse aggregate 2- When the size of aggregate is 475mm and less, it is called fine aggregate 3 When the size of aggregate 475 mm, it is called coarse as well as fine aggregate Of these statements :
A. statement 1 is correct
B. statement 2 is correct
C. statements 1, 2 are correct
D. statements 2, 3 are correct

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271.  Consider the following statements regarding aggregates: 1 Dry aggregates absorb water from the mixing water and thus affect the workability 2 Aggregates containing surface moisture contribute extra 3 The free moisture content in fine aggregate results in reduction of volume4 The free moisture content in coarse aggregate results in bulking of volumeOf these statements :
A. statement 1 and 2 are correct
B. statement 2 and 3 are correct
C. statement 3 and 4 are correct
D. statement 1 and 4 are correct

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272. Consider the following statements regarding the use of air entrainment on the properties of concrete 1 Reduction in the tendencies of segregation 2 Reduction in bleeding 3 Reduction in permeability 4 Reduction in the resistance to chemical attack Of these statements
A. statement 1 alone to correct
B. statement 1, 2 are correct
C. staetment 1, 2, 3 are correct
D. staetment 1, 2, 3, 4 aer correct

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