This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Sampling”.
1. ”Portland cement is composed of four major oxides (CaO, SiO2, Al2O3, Fe2O3 ≥90%)”. Is this statement true or false.
Explanation: Portland cement is composed of four major oxides (CaO, SiO2, Al2O3, Fe2O3 ≥90%) & some minor oxides. Minor refers to the quantity not importance.
2. What is the approx amount of lime is present in cement?
Explanation: Deficiency in lime reduces the strength of cement. Deficiency in lime causes cement to set quickly.
3. What is the approx amount of silica is present in cement?
Explanation: Sufficient quantity of silica should be present in cement to dicalcium and tricalcium silicate.
4. What is the amount of Na2O & K2O in P.C. ?
Explanation: Alkalies (Na2O & K2O) may cause some difficulties if the cement is used with certain types of reactive aggregates in making concrete.
5. Insoluble Residue mainly comes from which compound?
Explanation: Insoluble Residue is that fraction of cement which is insoluble in HCl. It comes mainly from the silica which has not reacted to form compounds during the burning process in the kiln.
6. Loss on Ignition (L.O.I.) is the loss in weight of cement after being heated to ___
Explanation: It indicates the prehydration or carbonation due to prolonged or improper storage of cement & clinker.
7. “C4AF is not a true compound.” Is this statement true or false?
Explanation: C4AF is not a true compound. The ferrite phase ranges from C2AF to C6AF. *C4AF represents an average.
8. On cooling below 1250oC, C3S decomposes __
d) Depends on the conditions
Explanation: On cooling below 1250oC, C3S decomposes slowly but, if cooling is not too slow, C3S remains unchanged and is relatively stable at ordinary temperatures.
9. If the moisture content of 5 to 10% by weight, then the bulking of sand is increased by __
Explanation: With the moisture content of 5 to 10% by weight, the bulking of sand is increased by 50.
10. When sand is fully dry then it’s volume is _____
d) Can’t say
Explanation: When the sand is fully dry then there is 0 bulking in it. Therefore, the volume of same will be same.
Sanfoundry Global Education & Learning Series – Concrete Technology.
To practice all areas of Concrete Technology, here is complete set of 1000+ Multiple Choice Questions and Answers.