In: Civil Engineering
A trapezoidal wall 2.75m in height has a bottom width 5m and upper width 4.5m. Determine quantity of cement and sand of mortar for CHB Laying using class A mixture for 10x20x40CHB
Let us assume the trapezoidal wall have the same thickness as of the CHB brick (10 cm).
Total block work is the total volume of the trapezoidal wall = =1.306 m3 (1)
Assuming 12% mortar content,
The quantity of wet mortar = 1.306 * 0.12 = 0.157 m3 (2)
Therefore,
Net block work = (1) - (2) = 1.306 - 0.157 = 1.149 m3 (3)
Total number of blocks = Net block work/ Volume of one block (4)
Volume of one block = (5)
From, (3), (4) & (5)
Total number of blocks = ~ 144 CHB blocks required.
Total qty of dry mortar = 1.27* Total qty of wet mortar
= 1.27*0.157 = 0.199 m3 (6)
Let us assume Cement mortar ratio is 1:3,
Sum of ratio = 1+3 = 4 (7)
From (6) & (7)
Total cement content = (0.199/4) = 0.05 m3 (8)
Volume of one bag of cement = 0.034 m3 (9)
From (8) & (9)
No. of cement bags required = 0.05/0.034 = 1.47 ~ 2 bags of cement
From (6) & (7)
Total sand content = (3/4)*(0.199) = 0.149 m3
Therefore,
Total number of CHB = 144 nos
Total cement content = 0.05 m3 ~ 2 bags of cement
Total sand content = 0.149 m3