MCQs on Ingredients of Concrete
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Q16: The maximum bulking of sand occurs at a water content between
Difficulty: Medium
Solution:
Bulking of sand is the increase in volume due to surface moisture. Maximum bulking occurs when the moisture content is between 4% and 5% by weight, after which adding more water starts to decrease the volume back to normal.
Q17: Seashore gravels are of which of the following types?
Difficulty: Easy
Solution:
Seashore gravels typically have a rounded shape. This is due to the continuous attrition and wearing action of water waves over a long period.
Q18: As per IS : 2386 (part – III) – 1963, the following formula of aggressive is given for : (Net weight of aggregate in kg) / (Capacity of container in litre)
Difficulty: Easy
Solution:
As per IS 2386 (Part III) – 1963, dividing the net weight of the aggregate (in kg) by the capacity of the container (in litres) yields the bulk density of the aggregate.
Q19: As per IS (383-1970), in how many zones are the Grading limits of fine aggregates distributed?
Difficulty: Easy
Solution:
According to IS 383:1970, the grading limits for fine aggregates are divided into 4 specific zones: Zone I, Zone II, Zone III, and Zone IV.
Q20: As per Indian Standard (IS 383 : 2016), the grading of fine aggregates is divided into how many zones?
Difficulty: Easy
Solution:
Even in the revised standard IS 383:2016, the grading of fine aggregates remains classified into four zones (Zone I, II, III, and IV).
Q21: The aggregates are classified as fine aggregates if their size is ________ and less :
Difficulty: Easy
Solution:
Aggregates that pass entirely through a 4.75 mm IS sieve are classified as fine aggregates, while those retained on it are considered coarse aggregates.
Q22: Arrange the following building materials in the increasing order of density of materials: Granite, Steel, River sand, Water
Difficulty: Medium
Solution:
The approximate densities are: Water (1000 kg/m3), River sand (1710 kg/m3), Granite (2640-2800 kg/m3), and Steel (7850 kg/m3). Thus, the increasing order is Water < River sand < Granite < Steel.
Q23: What will be the percentage of passing aggregate for the grading zone 1 of sieve size 1.18 mm?
Difficulty: Hard
Solution:
According to IS 383:1970, for fine aggregate falling under grading Zone 1, the percentage passing through a 1.18 mm IS sieve is between 30% and 70%.
Q24: The binding material in the mortar is also called:
Difficulty: Medium
Solution:
In a mortar or concrete mixture, the binding material (cement or lime paste) that holds the inert aggregates together is referred to as the matrix.
Q25: Which of the following cement is supposed to be the best cementing material and is well burnt cement?
Difficulty: Medium
Solution:
Tricalcium silicate (C3S) is considered the best cementing material. It hydrates rapidly, provides high early strength, and is formed when the clinker is well burnt.
Q26: If the least lateral dimension of aggregate is less than 0.6 times of its mean dimension, the aggregate is classified as
Difficulty: Medium
Solution:
An aggregate particle is classified as flaky if its least dimension (thickness) is less than 0.6 times (or 3/5ths) of its mean dimension.
Q27: Spot the odd statement
Difficulty: Easy
Solution:
Rounded, irregular, and angular flaky describe the physical ‘shape’ of aggregates, whereas ‘single-size’ describes the ‘grading’ (size distribution) of the aggregate.
Q28: Deleterious substances in aggregate are undesirable beacause they may:
Difficulty: Easy
Solution:
Deleterious substances like clay lumps, silt, or organic matter are undesirable because they interfere with cement hydration, have intrinsic weaknesses, and negatively impact strength, workability, and durability.
Q29: If a grading curve is horizontal between the portions of 20 mm I.S. Sieve and 4.75 mm I.S. sieve, the graded aggregates do not contain
Difficulty: Medium
Solution:
A horizontal line between 20 mm and 4.75 mm on a grading curve represents ‘gap grading’, meaning no particles of intermediate sizes (such as 10 mm) are present. The official answer key marks D (All options are correct).
Q30: Which of the following statements is true?
Difficulty: Medium
Solution:
All the statements are correct. The quality of water is critical for strength, the required quantity depends on aggregate grading and compaction, and adding 10% excess water significantly drops concrete strength (by around 15%).