ABSTRACT
Equivalent maturity (degree hours) calculated as the age of the concrete in hours multiplied by the number of degrees Celsius by which the average surface temperature of the concrete exceeds 10ºC
Other SRPC OPC or RHPC Other SRPC
OPC or RHPC
1. Hot weather or
drying winds 7 4 3 3500 2000 1500 2. Conditions not
covered by 1 4 3 2 2000 1500 1000
KEY OPC - Ordinary Portland Cement
RHPC - Rapid-hardening Portland cement
SRPC - Sulphate-resisting Portland cement Minimum period before striking formwork
Minimum period before striking
Surface temperature of concrete
16 º C 17 º C t º C(0-25) Vertical formwork to columns, walls and large beams 12 hours 18 hours 300 hours
t+10 Soffit formwork to slabs 4 days 6 days 100 days
t+10 Props to slabs 10 days 15 days 250 days
t+10 Soffit formwork to beams 9 days 14 days 230 days
t+10 Props to beams 14 days 21 days 360 days
t+10
MASONRY Weights of Bricks and Blocks
Walls and components of walls kg/m² lb/sq ft per mm thick per inch thick Blockwork Hollow clay blocks; average) 1.15 6 Common clay blocks 1.90 10 Brickwork Engineering clay bricks 2.30 12 Refractory bricks 1.15 6 Sand-lime (and similar) bricks 2.02 10.5
Weights of Stones
Type of stone kg/m3 lb/cu ft
Natural stone (solid) Granite 2560 to 2927 160 to 183 Limestone - Bath stone 2081 130 - Marble 2723 170 - Portland stone 2244 140 Sandstone 2244 to 2407 140 to 150 Slate 2880 180 Stone rubble (packed) 2244 140
Quantities of Bricks and Mortar
Materials per m² of wall:
Thickness No. of Bricks Mortar m³ Half brick (112.5 mm) 58 0.022 One brick (225 mm) 116 0.055 Cavity, both skins (275 mm) 116 0.045 1.5 brick (337 mm) 174 0.074 Mass brickwork per m³ 464 0.36
Mortar Mixes: Quantities of Dry Materials Imperial cu yd Metric m³ Mix Cement Lime Sand Cement Lime Sand cwts cwts cu yds tonnes tonnes cu m 1:3 7.0 - 1.04 0.54 - 1.10 1:4 6.3 - 1.10 0.40 - 1.20 1:1:6 3.9 1.6 1.10 0.27 0.13 1.10 1:2:9 2.6 2.1 1.10 0.20 0.15 1.20 0:1:3 - 3.3 1.10 - 0.27 1.00
Mortar Mixes for Various Uses
Mix Use
1:3 Construction designed to withstand heavy loads in all seasons.
