✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is the softening point? Bitumen doesn’t melt at one exact temperature; it slowly becomes softer as it warms. The softening point is the temperature at which a bitumen disc, carrying a small steel ball, sags 25 mm under standard heating. Higher
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is the penetration test? It measures how hard or soft bitumen is. A standard needle carrying 100 g is allowed to sink into bitumen at 25 °C for 5 seconds. The depth is measured in units of 0.1 mm. Higher penetration
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is specific gravity of bitumen? It tells you how heavy bitumen is compared with the same volume of water at 27 °C. Paving bitumen is usually just a little heavier than water, around 1.01–1.05. Why it matters: it’s needed to work
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is this test? It finds the compressive strength of cement by making small mortar cubes (cement + standard sand + water), curing them in water and crushing them at 3, 7 and 28 days. Why it matters: strength is the most
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What are setting times? When water is added to cement, the paste slowly stiffens and hardens. Initial setting time: the time when the paste starts to lose its plasticity. Concrete must be mixed, transported, placed and compacted before this. Final setting time:
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is standard consistency? It is the amount of water (as % of cement weight) that makes a cement paste of a standard “thickness”. It is found with the Vicat apparatus: the paste is right when the Vicat plunger sinks to 5–7
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is fineness of cement? It tells you how finely the cement has been ground. In this test we sieve cement through a very fine 90 micron sieve and weigh what stays on it (the coarse part). Why it matters: finer cement
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is specific gravity of cement? It tells you how heavy the cement is compared with the same volume of water. Ordinary Portland cement is about 3.15 times heavier than water. How is it measured? A known weight of cement is added
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is stripping? In a bituminous road, every stone is coated with a thin film of bitumen. If water gets between the stone and the bitumen, the film peels off (strips). The road then loses strength and develops ravelling, potholes and loose
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✓Written by Help The Engineer TeamReviewed by Er. Inderjit Sharma (Retd.), Punjab PWD What is the Ten Percent Fines Value (TFV)? It is the load (in kN) needed to crush the aggregate so that 10% of it turns into fines (passing the 2.36 mm sieve). Higher TFV = stronger stone. A stone needing 200 kN
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