Ready mixed mortar ~ this is delivered dry for storage in purpose
made silos with integral mixers as an alternative to site blending
and mixing. This ensures:
- Guaranteed factory quality controlled product
- Convenience
- Mix consistency between batches
- Convenient facility for satisfying variable demand
- Limited wastage
- Optimum use of site space
Mortar and cement strength ~ see also page 354. Test samples
are made in prisms of 40¾40 mm cross section, 160 mm long. At
28 days samples are broken in half to test for flexural strength.
The broken pieces are subject to a compression test across the
40 mm width. An approximate comparison between mortar strength
(MN/m^2 or N/mm^2 ), mortar designations (i to v) and proportional
mix ratios is shown in the classification table below. Included is
guidance on application.
Proportional mixing of mortar constituents by volume is otherwise
known as a prescribed mix or simply a recipe.
Mortar classification ~
Relevant standards;
BS 5628-3: Code of practice for use of masonry. Materials and
components, design and workmanship.
BS EN 196: Methods of testing cement.
BS EN 998-2: Specification for mortar for masonry. Masonry
mortar.
PD 6678: Guide to the specification of masonry mortar.
BS EN 1015: Methods of test for mortar for masonry.
Traditional BS EN 998-2 Proportions by volume
designation Strength cement/lime/sand cement/sand Application
i 12 1:0.25:3 1:3 Exposed external
ii 6 1:0.5:4†4.5 1:3†4 General external
iii 4 1:1:5†6 1:5†6 Sheltered internal
iv 2 1:2:8†9 1:7†8 General internal
v † 1:3:10†12 1:9†10 Internal, groutingMortars for Brickwork and Blockwork (2)