63) If is % of air void, S is the degree of saturation & e is a void ratio, then which of the following relationship is correct.
a) n_a= e x (1x S)/(1+e)
b) n_a= e x (1/S)/(1-e)
c) n_a= e x (1-S)/(1-e)
d) n_a= e x (1-S)/(1+e)
Answer: d) ) n_a= e x (1-S)/(1+e)
- The percentage of air voids is the ratio of the volume of air to the total volume.
i.e., n_a= V_a/V
- When we subtract the volume of water from the volume of a void, we will get the air volume.
- Va = Vv – Vw = e – e_w & V = Vs +Vv = 1+e
∴ n_a= (e – e_w)/(1+e ) ;
- since e_w= eS Hence, the formula of a percentage of air void in terms of void ratio & degree of saturation is given below;
∴n_a= e x (1-S)/(1+e)