PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

The water cement ratio may be as under or as directed by the Engineer.
Cement Sand Water – Cement ratio
Quantity of water per
50 kg. of cement
(Litres)
1 1 0.25 12.5
1 1 ½ 0.28 14.0
1 2 0.30 15.0
1 2 ½ 0.35 17.5
1 3 0.40 20.0
1 4 0.53 26.5
1 5 0.60 30.0
1 6 0.70 35.0
1 8 0.90 45.0
Machine mixed mortar shall be prepared in an approved mixer. Water cement ratio
shall be as per hand mixed mortar. The mortar so prepared shall be used within
30 minutes of adding water. The mortar remaining unused after that period, mortar,
which has partially hardened or is otherwise damaged shall not be re tempered or
remixed. It shall be destroyed or thrown away.
10.4 Preparation of Background for Application of Plaster.
Cleanliness:
All dirt, dust and other foreign matter on masonry and laitance on the concrete
surfaces shall be removed by watering and brushing as required. If the background
contains soluble salts particularly sulphates, the application of plaster shall be done
only after the efflorescence of the salts is complete and the efflorescence is
completely removed from the surface.
Joints in brickwork, stone masonry and hollow block, masonry shall be raked out to
a depth of not less than 10mm as the work proceeds. Local projection in brickwork
and masonry beyond the general wall face shall be trimmed off where necessary.
GTS : General Technical Specification. Page 80