10
Red earth.
Water.
Cement mortar,
Cement-
Lime Mortar,
Lime
mortar.
BUILDING (CONSTRUCTION) REGULATIONS, 1956
(d) contain no greater proportion of fine clay, silt or fine dust (being such clay, silt or dust as will pass through a 0.com inches sieve) than 5 per cent by weight in the case of naturally occurring sand, and to per cent by weight 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 concretc 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 barmful
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 morlar 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 11.
TABLE 11. Cement-lime mortar.
Maximum ratio of the volume of cement to the volume of sand
Lime
Sand
Cement
Min. Max.
Cement- Lime
Min. Max.
1
1
1
*2
1 : 12 where atone lime is used.
I : 9 where shell lime is used.
Note: -Not more than 95% of the volume of sand may be replaced
by an equal volume of red earth.
17. (1) Lime mortar shall be composed of stone lime or shell lime, sand or red earth mixed by volume in the proportions shown in Table 111.
BUILDING (CONSTRUCTION) REGULATIONS, 1966
(2) Lime mortar with a base of shell lime shall not be used in the construction of any external load bearing wall.
TABLE ILL.
Line mortar,
Stone Lime
Shell Lime
Bod
1
26 1
1 to 2
Note:-Not more than 25% of the volume of sand may be
replaced by an equal volume of red earth.
11
18. (1) Aggregate for plain concrete shall consist of sand, Aggregate. well-burnt brick, well-burnt tile, well-burnt clinker, stone or any other material of which the Building Authority may approve. It shall be so gruded as to make a sound concrete.
(2) Aggregate for reinforced concrete shall- (a) consist of sand and crushed stone;
(b) be hard, strong and durable and reasonably clean and
free from clay, organic or other harmful matter;
(c) being fine aggregate, be of such size that at least go per cent by weight will pass a 3/16 inch mesh screen, and not more than 15 per cent by weight will pass a No. 100 mesh, British Standard Specification;
(d) being coarse aggregate, be of such size that—
(i) not more than 10 per cent by weight will pass a 3/16 inch mesh screen;
(ii) at least 95 per cent by weight will pass a mesh of a size 1 inch less than the minimum lateral distance between reinforcing bars, or 4 inch less than the minimum cover, whichever is the smaller, or in the case of solid slabs will pass 4 inch mesh screen;
(e) be so graded as to make a dense concrete.
19. (1) Concrete shall be composed of aggregate mixed with Concrete. cement and water.
(2) The fine aggregate and coarse aggregate shall be measured separately.
(3) The proportions of cement to aggregate shall be-
(a) those specified in Tables IV and V for the appropriate
grade of concrete; or