51) The compaction of concrete improves

• (a) density
• (b) strength
• (c) durability
• (d) all of these

52) The workability of concrete for a given water content is good if the aggregates are

• (a) rounded aggregate
• (b) irregular aggregate
• (c) angular aggregate
• (d) flaky aggregate

53) Which of the following decreases the workability of concrete?

• (a) Well graded aggregate
• (b) Air entraining admixture
• (c) Angular aggregates
• (d) Rounded aggregates

54) Which of the following property of the concrete is determined using a compaction factor test?

• (a) Workability of concrete
• (b) Strength of concrete
• (c) Density of concrete
• (d) Porosity of concrete

55) The strength of cement concrete increases with

• (a) increase in the size of aggregate
• (b) increase in the temperature of water of curing
• (c) increase in the size of aggregate
• (d) all of the above