engineering recuitment BARC Stipendiary Trainee Category I 2023 Mock Test Construction Materials and Management Concrete
Mean target strength [ft] is given by (Where fck is 28-day Characteristic compressive strength and 'σ ' is Standards deviation.)
1
ft = fck + 0.65 σ
2
ft = fck - 1.65 σ
3
ft = fck + 1.65 σ
4
ft = fck - 0.65 σ