Guide to Bricklaying
Mortar binds bricks and blocks together to give strength and stability to a wall. Freshly mixed mortar must be soft and flexible, so that it spreads easily and makes good contact, without becoming too strong in its hardened state. Too strong a mortar may crack and is wasteful, as it is more expensive.
The properties of mortar in both the fresh and hardened states depend to a large extent on the properties of the materials used. This section gives guidance on selecting materials.
All AfriSam Cement products comply with SANS 50197-1: and bear the SABS mark. For instructions on making high quality mortar mixes, refer to AfriSam Cement product brochure for the particular AfriSam product being used.
Sand is by far the major constituent of a mortar mix and has a significant influence on its performance and material cost. The sand should be clean (grass, leaves, roots and other foreign matter are harmful) and it should not contain too much clay. It should consist of hard particles ranging in size from dust up to about 2 mm. Pit sands generally have these characteristics. Dune and beach sands are often too uniform in size (single sized) to give good results.
Building lime should be used if the sand lacks fine material or is single sized, as such sands tend to produce mortar with poor workability. The amount added to the mix may be as much as the amount of cement by volume and site trials is advisable.
Note: The limes used in South Africa do not have cementing properties. They can therefore not be used to replace cement but are used in addition to cement.
The proportion of each material in the mix should
suit the type of work being done. Strength classes and corresponding mix proportions are given in AfriSam Cement product brochure for the particular product being used.
In general terms there are three classes of mortar.
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