Civil Engineering Basic Knowledge:
I will discuss civil engineering basic knowledge. this knowledge is very important for every civil engineering student. if they are working on construction site if they are studying even if they are free so you should learn about the basic knowledge.
#1. Grade Of Concrete
Grade Of Concrete

Mix Ratio
C : S : A

M7.5 
1:4:8 
M10 
1:3:6 
M15 
1:2:4 
M20 
1:1.5:3 
M25 
1:1:2 
#2. Unit Weight of Civil Engineering Materials
Materials 
Unit Weight (kg/m³) 
Cement 
1440 
P.C.C 
2400 
R.C.C 
2500 
Cement Plaster 
2000 
Bitumen 
1340 
Glass 
2500 
Water 
1000 
#3. Standard Conversion Factor
1 Meter 
3.28 feet 
1 Meter 
39.37 inches 
1 Meter 
100 cm 
1 Meter 
1000 mm 
1 Foot 
12 inches 
1 Inch 
2.54 cm 
1 Inch 
8 soot 
#4. Clear Cover For Different R.C.C Members
Member 
Clear Cover 
Foundation 
75 mm 
Raft Foundation 
Top= 50mm
Bottom= 75mm
Sides= 75mm 
Strap beam 
50mm 
Beam 
25mm 
Column 
40mm 
Flat Slab 
20mm 
Slab 
15mm 
#5. Unit Weight Of Steel per Meters
Diameter of Steel 
Weight kg/m 
6mm 
0.222 
8mm 
0.395 
10mm 
0.616 
12mm 
0.888 
16mm 
1.578 
20mm 
2.466 
25mm 
3.853 
#6. Basic Area Units
1 Kanal 
20 Marla 
1 Marla 
272.24 sq. ft. 
1 Kanal 
502 meter square 
1 Marla 
25.10 square meter 
1 Hectare 
10000 sq. m 
1 Acre 
43560 sq. ft. 
#7. Curing of Types of Cement
1. For O.P.C ( ordinary portland cement ) 
7 Days 
2. super sulphate cement 
10 Days 
3. cement with mineral & admixture 
14 Days 
#8. Grade of Steel
Tensile Strength
1. Mild Steel 
Fe 250 
250 N/mm² 
2. HYSD ( high yield strength deformed bars ) 
Fe 415 
415 N/mm² 
Fe 500 
500 N/mm² 
3. TMT Bars ( Thermo mechanically treated bars ) 
Fe 415 
415 N/mm² 
Fe 500 
500 N/mm² 
Fe 550 
550 N/mm² 
#9. Setting Time of Cement
Types of Cement 
Initial Setting Time 
Final Setting Time 
O.P.C ( ordinary portland cement) 
30 minutes 
600 minutes 
Portland blastfurnace cement 
30 minutes 
600 minutes 
RHC ( rapid hardening cement) 
30 minutes 
600 minutes 
LHC ( low heat cement ) 
60 minutes 
600 minutes 
#10. Grade of OPC ( ordinary portland cement )
33 Grade 
33 N/mm² 
43 Grade 
43 N/mm² 
53 Grade 
53 N/mm² 
#11. Crushing Strength of Bricks
Types of Brick 
Crushing Strength 
First Class Brick 
105 kg/mm² 
2nd Class Brick 
70 kg/mm² 
3rd Class Brick 
35 kg/mm² 
#12. Water Absorption of Brick
1st Class Brick 
<less than 15% by weight 
2nd Class Brick 
< less than 20% by weight 
3rd Class Brick 
> greater than 22% by weight 
#13. Water Absorption Of Building Stone
 Water absorption of building stone is not greater than 5% by weight.
FAQ or Short Notes:
 The weight of 1 bag of cement is 50 kgs.
 The density of cement is 1440 kgs/m³
 The minimum thickness of the slab should be a minimum of 0.125 meters are 125 millimeters
 The fourth one is c/c means central to central distance. so c/c especially we are using in steel structure design for the slab or for any RCC members we can say spacing between two steel rods.
 The thickness of DPC damproof cores should not be less than 2.5 centimeters or 1 inch.
 DL means development length. development length is which makes a good bond between steel and concrete.
 The slope of the stair should be between 25 to 40 angles. the riser and stair in between 150 to 200. the trade should be 250 to 300 mm. the vertical portion of the stair is rising.
 550 numbers bricks are required in a onemeter cube.
 M20 grid concrete is generally used in the construction of slabs. so what is m20 grade concrete m20 means the M20 ratio is 1:1.5:3
 Unit weight of steel the formula is D²/162 in kg/m. for example, am using the dia this is steel rod okay which dia is 12 millimeters okay so the formula will be 12*12/162 = 0.88 kg/m
 Lapping should not be provided for the dia more than 36 mm.
 The maximum free fall height of concrete should not be more than 1.5 meters so the max very far should not be more than 1.5 meters otherwise it will make bleeding, segregation, etc.
 The compressive strength of brick is 7.5 N/mm²
 The number of bars = length of the opposite side divided by spacing c/c plus 1. then you can find the total numbers of steel rods.
 Longitudinal reinforcement should not be less than 0.8% and more than 6% of gross C/S.
 The minimum bars used for a square column are 4 No’s and 6 No’s for the circular column.
 The curing time for concrete members is 7 to 10 days.
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