176.  If a grading curve is horizontal betwen the portions of 20 mm IS Sieve and 475 mm I S Sieve, the graded aggregates do not contain
A. 20 mm particles
B. 10 mm particles
C. 475 mm particles
D. all the above

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177.  For the construction of cement concerte dams, the maximum permissible size of the aggregates, is
A. 40 mm
B. 50 mm
C. 60 mm
D. 70 mm

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178. For the construction of cement concrete floor, the maximum permissible size of aggregate, is
A. 4 mm
B. 6 mm
C. 8 mm
D. 10 mm

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179.  The most useless aggregate is one whose surface texture is
A. smooth
B. granular
C. glassy
D. honey combed & porous

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180.  Pick up the correct statement from the following :
A. According to the petrological characteristics, concrete aggregates are classified as heavy weight, normal weight and light weight
B. According to the shape of the particles, concrete aggregates are classified as rounded rregular, angular and flaky
C. According to the surface texture of the particles, the concrete aggregates are classified as glassy, smooth, - granular, rough, crystalline, honey combed and porous
D. All the above

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181.  The light weight aggregates are obtained from
A. sedimentary rocks
B. metamorphic rocks
C. igneous rocks
D. volcanic source

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182.  To obtain a very high strength concrete, use very fine grained
A. Granite
B. Magnetite
C. Barite
D. Volcanic scoria

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