🧱 Materials Engineer Accreditation Exam Reviewer – Part 4 Concrete and Aggregates Testing, Mixing, Placement
📘 Topic Focus: Concrete and Aggregates Testing, Mixing, Placement
✍️ Total Questions: 25
🔍 Based on: DPWH Blue Book 2024 Edition
👷 Instructions: Select the correct answer. Answer key is provided at the end for self-checking.
🧠 Knowledge Check – Concrete and Aggregates
- What is the standard compressive strength test age for concrete samples?
A. 3 days
B. 7 days
C. 14 days
D. 28 days - Which test is used to determine the workability of fresh concrete?
A. Compressive strength test
B. Slump test
C. Split-tensile test
D. Flexural test - Which ASTM standard refers to standard concrete cylinder testing?
A. ASTM D1557
B. ASTM C39
C. ASTM C131
D. ASTM D698 - The ratio of water to cement by weight is called:
A. Water-cement ratio
B. Slump ratio
C. Plasticity index
D. Admixture ratio - What is the allowable maximum slump for Class A concrete?
A. 25 mm
B. 75 mm
C. 100 mm
D. 150 mm - The fine aggregates shall pass through which sieve size?
A. 1/2 inch
B. 3/8 inch
C. 4.75 mm (No. 4)
D. 19 mm - The durability of concrete depends greatly on:
A. Slump
B. Aggregate size
C. Water-cement ratio
D. Formwork - Which admixture is used to slow down the setting time of concrete?
A. Accelerator
B. Retarder
C. Plasticizer
D. Air-entrainer - What is the maximum allowable temperature for freshly mixed concrete as per DPWH standards?
A. 25°C
B. 30°C
C. 32°C
D. 35°C - Concrete is considered cured when it reaches how much of its design strength?
A. 50%
B. 75%
C. 90%
D. 100% - Which aggregate property affects the water demand of a concrete mix?
A. Size
B. Shape
C. Surface texture
D. All of the above - What test is used to determine aggregate abrasion resistance?
A. Los Angeles Abrasion Test
B. CBR Test
C. Marshall Test
D. Compression Test - Bulking of sand is affected by:
A. Aggregate shape
B. Water content
C. Cement type
D. Coarse aggregate size - Which test checks for deleterious materials in aggregates?
A. Sieve analysis
B. Soundness test
C. Organic impurities test
D. Specific gravity test - Minimum curing period for concrete exposed to drying conditions per DPWH:
A. 3 days
B. 7 days
C. 14 days
D. 28 days - Admixtures are used in concrete primarily to:
A. Reduce cost
B. Alter properties
C. Change color
D. Improve flowability only - The maximum size of coarse aggregate should be:
A. Less than 1/3 of slab thickness
B. 25 mm always
C. Same as maximum slump
D. Greater than rebar spacing - What is the ideal shape of coarse aggregate for good workability?
A. Rounded
B. Flat
C. Elongated
D. Irregular - For water-cement ratio of 0.5, how much water is needed per 50 kg of cement?
A. 15 L
B. 20 L
C. 25 L
D. 30 L - Coarse aggregates are generally retained on what sieve size?
A. No. 4
B. No. 8
C. 10 mm
D. 4.75 mm - During slump testing, if the cone collapses, it means:
A. Very stiff mix
B. Over-vibration
C. Too wet mix
D. Proper workability - Which curing method maintains humidity without adding water?
A. Ponding
B. Wet burlap
C. Curing compound
D. Steam curing - Concrete bleeding is caused by:
A. Aggregate segregation
B. Poor cement quality
C. Excess water
D. Use of admixtures - The unit weight of normal concrete is approximately:
A. 1500 kg/m³
B. 2000 kg/m³
C. 2300 kg/m³
D. 2400 kg/m³ - For concrete exposed to marine conditions, what type of cement is preferred?
A. Type I
B. Type II
C. Type III
D. Type V
📋 Answer Key
1. D 2. B 3. B 4. A 5. B
6. C 7. C 8. B 9. C 10. C
11. D 12. A 13. B 14. C 15. B
16. B 17. A 18. A 19. C 20. A
21. C 22. C 23. C 24. D 25. D
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