B 12
[Subsidiary]
Sand.
L.N. 294/76.
Red earth.
Water.
Cement mortar.
Cement-lime mortar.
CAP. 123] Building (Construction) Regulations
12. (1) Sand shall---
[1985 Ed.
(a) consist of naturally occurring sand, crushed stone or a
combination of both;
(b) be hard, clean and free from adherent coatings;
(c) contain no appreciable amount of clay balls or pellets;
(d) contain no greater proportion of fine clay, silt or fine dust (being such clay, silt or dust as will pass through a 25 μm sieve) than-
(i) 5 per cent by mass in the case of naturally occurring sand; and
(ii) 10 per cent by mass in the case of crushed stone.
(2) Sand shall contain no harmful material in sufficient quantity adversely to affect the hardening strength or durability of the mortar, plaster or concrete, or, in the case of reinforced concrete, to attack the reinforcement.
13. Red earth shall consist of decomposed rock containing not more than 15 per cent of clay. It shall contain no harmful material in sufficient quantity adversely to affect the hardening strength or durability of the mortar or plaster.
14. Water shall be clean fresh water free from harmful matter.
15. (1) Cement mortar shall be composed of cement and sand in the proportion of one volume of cement to not less than 2 nor more than 4 volumes of sand.
(2) Lime or red earth may be added to such cement mortar in the proportion of not more than 25 per cent of the cement in volume.
16. Cement-lime mortar shall be composed of cement, sand and stone lime or shell lime, mixed by volume in the proportions shown in Table II.
TABLE II
Cement-lime mortar
Cement Lime Sand Cement-lime Min. Max. 1 ... 4 1 2 7 Maximum ratio of the volume of cement to the volume of sand 1:12 where stone lime is used. 1:9 where shell lime is used.Note: Not more than 25 per cent of the volume of sand may be replaced by an equal volume of red earth.