Mortar Specifications and Mix Types

Mortar Specifications

• No mortar plasticizers or set-retarding admixtures should be introduced unless specifically allowed.
• Changes to sand and cement types in strength mortar are permitted only if tests confirm the desired strength.
• Consistent control over material proportions for mortar mix is essential during measurement and construction.

Prescribed-Mix Mortar

• Mortar mix proportions are outlined in Table 7.
• Class I Mortar:
  • Common cements: 50 kg cement, 0-10 kg lime, max. aggregate size of 130 mm, equivalent to 2 standard wheelbarrows.
  • Masonry cements (MC 22.5 X, MC 12.5): 50 kg cement, no lime, max. aggregate size of 80 mm, equivalent to 1 standard wheelbarrow.
• Class II Mortar:
  • Common cements: 50 kg cement, 0-25 kg lime, max. aggregate size of 200 mm, equivalent to 3 standard wheelbarrows.
  • Masonry cements (MC 22.5 X, MC 12.5): 50 kg cement, no lime, max. aggregate size of 130 mm, equivalent to 2 standard wheelbarrows.

Cement Measurement Guidelines

• Cement should always be measured by weight, not volume.
• A factory-packed 50 kg bag of common cement occupies approximately 33 L but may increase by up to 20% in bulk when poured, affecting measurement accuracy.
• It is recommended to use whole bags for volume batching due to variances in bulk density.

Lime Usage

• The use of lime with common cements is permitted within the specified maximum limits but cannot substitute for cement in the mix.

Wheelbarrow Specifications

• A standard wheelbarrow, conforming to SANS 795 (type 2), has a capacity ranging from 60 L to 70 L.