Reinforced Cavity Wall Construction Quiz

A minimum strength of 15 MPa is generally required for infill concrete in reinforced cavity walls.

While cement bricks can be used for support, they are not an acceptable substitute for reinforcing mesh or rebar.

Mortar should be used within one hour of mixing for optimal performance.

Mortar that has begun to set (hard thumbprint) should be used within two hours of mixing. This ensures proper bonding.

A masonry wall should not overhang the concrete slab of raft foundations by more than 30mm to prevent uneven settling.

Concrete bricks require wetting prior to placement to prevent rapid moisture absorption from the mortar, which can affect bond.

Mortar used in hollow bricks for cavity wall foundations should have a grading of 1.0 MPa and 10.0 MPa.

The average compressive strengths for hollow and solid masonry units in single-storey buildings are 7.0 MPa and 10.0 MPa respectively.

The average compressive strengths for hollow and solid masonry units in the lower storey of a double-storey building are 3.0 MPa and 7.0 MPa respectively.

The average compressive strength for solid masonry units in a double-storey construction is 15 MPa.

The minimum difference in ground levels (h) for a 110-110 cavity retaining wall should be 1200 mm.

The text does not specify a maximum height for a masonry foundation wall retaining fill behind a 220mm nominal wall thickness.

20 MPa is the recommended minimum compressive strength for concrete infill in cavity wall construction.

Cement mortar is typically used in laying masonry units for wall construction.

Cement bricks cannot substitute steel reinforcement in masonry wall construction. Steel reinforcement is mandatory for structural integrity.

The maximum size of rock or hard fragments allowed in backfill material for masonry wall construction is 50 mm.

The minimum horizontal spacing requirement between a water pipe and a sewer line when laid underground is 600 mm. This helps prevent interference and potential leaks.

A minimum slab thickness of 250 mm is recommended for non-load-bearing masonry walls to provide adequate support and stability.