Field tests for assessing quality of cement — identify the incorrect statements Consider the following common field checks for a bag of good quality Portland cement: (a) Thrusting a hand into the bag should feel warm. (b) The colour of the cement is bluish. (c) A handful of cement sprinkled or thrown into a bucket of water should sink immediately without floating. (d) When rubbed between fingers, the cement should feel rough. Which option correctly identifies the set of statements that are incorrect for good cement?

Introduction / Context:
Simple field tests help quickly screen cement quality on site before batching concrete or mortar. While not a substitute for laboratory tests, these checks can flag obviously deteriorated cement affected by moisture, carbonation, or prolonged storage. This question asks you to identify which statements do not match the expected observations for sound, fresh cement.

Given Data / Assumptions:

• Cement under consideration is ordinary Portland cement stored properly in sealed bags.
• Field checks are qualitative and indicative, not definitive compliance tests.
• We compare observations against standard site lore and practical guides.

Concept / Approach:

Fresh, healthy cement has a characteristic greenish-grey colour (not bluish), feels cool and smooth to the touch, is free from lumps, and when lightly sprinkled on water it should sink rather than float. Warmth in the bag indicates ongoing hydration from moisture ingress, which is undesirable. A rough feel suggests contamination, coarseness, or partial setting. Therefore, we must isolate the incorrect statements and exclude the correct one about sinking in water.

Step-by-Step Solution:

Verification / Alternative check:

Standard handbooks list cool feel, greenish-grey colour, absence of lumps, and immediate sinking on water contact as quick checks. Any deviation (warmth, bluish tint, rough feel) warrants caution and further testing.

Why Other Options Are Wrong:

• (b), (e) isolate single items and ignore other incorrect ones.
• (d) “All” is false because statement (c) is actually correct.
• (b) “Only (a)” omits (b) and (d) which are also incorrect.

Common Pitfalls:

• Confusing bluish cast with greenish-grey; lighting can mislead the eye.
• Judging solely by touch; always check for lumps and clodding too.

Final Answer:

Only (a), (b), and (d) are incorrect.