Coloured mortars

Mortar colour has a profound effect on the overall appearance of the brickwork as, with stretcher bond and a standard 10 mm joint, the mortar accounts for 17% of the brickwork surface area. A wide range of light-fast coloured mortars is available which can be used to match or contrast with the bricks, thus highlighting the bricks as units or creating a unity within the brickwork. The coloured mortars contain inert pigments, which are factory-blended to a tight specification to ensure close colour matching between batches. Occasionally, black mortars may bloom due to lime migration to the surface. Coloured mortars can be used creatively to enhance the visual impact of the brickwork and even create designs on sections of otherwise monochromatic brickwork. The quantity of pigment should not exceed10% by weight of the cement. Mortar colours may also be modified by the use of stains after curing; however, such applications only penetrate 2 mm into the surface, and therefore tend to be used more for remedial work. Through-body colours are generally more durable than surface applications.

(From Materials for Architects and Builders)

LANGUAGE FOCUS

9 Use the words below to complete the sentences:

CLAY BRICKS

Part I

The main constituents of brick-making clays are silica (sand) and 1) _____, but with varying quantities of chalk, 2) _____, iron oxide and other minor constituents such as fireclay, according to their source.

There are five main processes in the manufacture of 3) _____ bricks: a) extraction of the raw material; b) forming processes; c) drying; d) firing; e) packaging and distribution.

The process begins with the 4) _____ of the raw material from the quarry and its transportation to the works, by conveyor belt or road transport. Topsoil and 5) _____ overburden are removed first and used for site reclamation after the 6) _____ clay is removed.

The handmade process involves the throwing of a suit ably sized clot of wet clay into a wooden 7) _____ on a bench. The surplus clay is struck off with a framed wire and the green brick removed. The bricks produced are 8) _____ in shape with soft arises and interestingly folded surfaces. Two variations of the process are 9) _____ moulding and slop moulding.

clay irregular lime unsuitable mould extraction pallet alumina usable

10 Fill in the gaps with derivatives of the words in capitals: