The Construction of Green Building …
45
Table 2 Concrete mix design form of grade 35 concrete
Stage Item
Reference
Values
1
1.1 Characteristic strength
Specified
35 N/mm 2 at 28 days
BS 5328,
BS 8110
5 % defective level for the design
and construction of concrete
structure
1.2 Standard deviation
Figure 3
8 N/mm 2
(less than 20 results are available)
1.3 Margin
Figure 1
5 % defectives, k = 1.64
1.64 × 8 = 13.12 N/mm 2
1.4 Target mean strength
35 + 13.12 = 48.12 N/mm 2
1.5 Cement strength class
Specified
42.5 or 52.5
1.6 Aggregate type: coarse
Aggregate type: fine
Crushed or Uncrushed
Crushed or Uncrushed
1.7 Free-water/cement ratio
Table 2,
Fig. 4
0.51
1.8 Maximum free-water/cement
ratio
BS 8110,
Table 3.3
0.60
– Use the lower value of
free-water/cement ratio
0.51
2
2.1 Slump or Vebe time
Slump 30 – 60 mm
2.2 Maximum Aggregate size
Crushed – 20 mm
2.3 Free-water content
Table 3
210 kg/m 3
3
3.1 Cement content
210/0.51 = 411.764 kg/m 3
3.2 Maximum cement content
3.3 Minimum cement content
300 kg/m 3
– Cement content
411.764 kg/m 3
4
4.1Relative density of aggregate
(SSD)
2.7 known
4.2 Concrete density
Figure 5
2400 kg/m 3
4.3 Total aggregate content
2400 – 411.764 – 210 =
1778.236 kg/m 3
5
5.1 Grading of fine aggregate
Percentage passing 600 µm sieve
= 65 %
5.2 Proportion of fine aggregate
Figure 6
33 %
5.3 Fine aggregate content
33% x 1778.236 = 586.818
kg/m 3
5.4 Coarse aggregate content
1778.236 – 586.818 = 1191.418
kg/m 3
45
Table 2 Concrete mix design form of grade 35 concrete
Stage Item
Reference
Values
1
1.1 Characteristic strength
Specified
35 N/mm 2 at 28 days
BS 5328,
BS 8110
5 % defective level for the design
and construction of concrete
structure
1.2 Standard deviation
Figure 3
8 N/mm 2
(less than 20 results are available)
1.3 Margin
Figure 1
5 % defectives, k = 1.64
1.64 × 8 = 13.12 N/mm 2
1.4 Target mean strength
35 + 13.12 = 48.12 N/mm 2
1.5 Cement strength class
Specified
42.5 or 52.5
1.6 Aggregate type: coarse
Aggregate type: fine
Crushed or Uncrushed
Crushed or Uncrushed
1.7 Free-water/cement ratio
Table 2,
Fig. 4
0.51
1.8 Maximum free-water/cement
ratio
BS 8110,
Table 3.3
0.60
– Use the lower value of
free-water/cement ratio
0.51
2
2.1 Slump or Vebe time
Slump 30 – 60 mm
2.2 Maximum Aggregate size
Crushed – 20 mm
2.3 Free-water content
Table 3
210 kg/m 3
3
3.1 Cement content
210/0.51 = 411.764 kg/m 3
3.2 Maximum cement content
3.3 Minimum cement content
300 kg/m 3
– Cement content
411.764 kg/m 3
4
4.1Relative density of aggregate
(SSD)
2.7 known
4.2 Concrete density
Figure 5
2400 kg/m 3
4.3 Total aggregate content
2400 – 411.764 – 210 =
1778.236 kg/m 3
5
5.1 Grading of fine aggregate
Percentage passing 600 µm sieve
= 65 %
5.2 Proportion of fine aggregate
Figure 6
33 %
5.3 Fine aggregate content
33% x 1778.236 = 586.818
kg/m 3
5.4 Coarse aggregate content
1778.236 – 586.818 = 1191.418
kg/m 3