# Important Things a Civil Engineer Must Know

**Important Things a Civil Engineer Must Know**

There are some certain important things a civil engineer must know before handling to a site, like such as basic terms, codes, values, tests etc….

**Some Important Test **

**Some important test on Fresh Concrete **

- Slump Test – Workability.
- Compacting Factor.
- Vee- Bee Test.

**Some important Test on Hardened Concrete **

As we know that there are many various tests available in the civil engineering field and also Various tests on Hardened Concrete is done to ensure the design and strength of concrete and quality of concrete construction are achieved. So let’s know about important Test on Hardened Concrete one by one.

Now a day’s some following Test is used on Hardened Concrete.

- Destructive Tests on Concrete
- Non-destructive Tests on Concrete
- Chemical Test on Concrete

**Densities of Various Construction Materials**

Here Some Following Materials Are Given Below.

- Density of Concrete: 2370 kg/m
^{3} - Density of Cement: 1440 kg/m
^{3} - Density of Cement Mortar: 2080 kg/m
^{3} - Density of Brick: 1600-1920 kg/m
^{3} - Density of Brick Masonry: 1920 kg/m
^{3} - Density of Dry Sand: 1600 kg/m3
- Density of River Sand: 1840 kg/m
^{3} - Density of PCC: 2240 kg/m
^{3} - Density of Steel: 7849 kg/m
^{3} - Density of Cast Iron: 7208 kg/m
^{3} - Density of RCC 2% Steel: 2420 kg/m
^{3} - Density of Aluminium: 2739 kg/m
^{3} - Density of Gravel with sand: 1920 kg/m
^{3} - Density of Crushed Stone: 1600 kg/m
^{3} - Density of 4 inches Brick w/½” mortar: 673 kg/m
^{3} - Density of 8-inch Concrete Block w/½” mortar: 881 kg/m
^{3} - Density of 12-inch Concrete Block w/½” mortar: 1281 kg/m
^{3} - Density of A. C. Sheet Corrugated: 16 kg/m
^{3} - Density of Teak Wood: 670–830 kg/m
^{3} - Density of 1/4 inch Plywood: 3.47 kg/m
^{3} - Density of 3/8 inch Plywood: 5.18 kg/m
^{3} - Density of 1/2 inch Plywood: 6.93 kg/m
^{3} - Density of 1/2 inch Gypsum: 7.62 kg/m
^{3} - Density of 3/8 inch Gypsum: 10.2 kg/m
^{3} - Density of Marble: 2560 kg/m
^{3} - Density of Limestone: 2739 kg/m
^{3} - Density of Granite Stone: 2460–2800 kg/m
^{3} - Density of Tar:1150 kg/m
^{3} - Density of Porcelain: 2400 kg/m
^{3} - Density of Window Glass: 2580 kg/m
^{3}

**Important Points to Remember for Civil Engineers**

Here Some points are given for civil engineers Step By Steps for Remember Please read all points carefully.

- Minimum thickness of slab is 125 mm.
- Water absorption should not be more than 15 %.
- Dimension tolerance for cubes + , – 2 mm.
- Lapping is not allowed for the bars having diameters more than 36 mm.
- Chair spacing maximum spacing is 1.00 m (or) 1 No per 1m2.
- For dowels rod minimum of 12 mm diameter should be used.
- Chairs minimum of 12 mm diameter bars to be used.
- Longitudinal reinforcement not less than 0.8% and more than 6% of gross C/S.
- Minimum bars for square column is 4 No’s and 6 No’s for circular column.
- Main bars in the slabs shall not be less than 8 mm (HYSD) or 10 mm (Plain bars) and the distributors not less than 8 mm and not more than 1/8 of slab thickness.
- Minimum thickness of the slab is 125 mm.
- Dimension tolerance for cubes + 2 mm.
- Free fall of concrete is allowed maximum to 1.50m.
- Lap slices not be used for bar larger than 36 mm.
- Water absorption of bricks should not be more than 15 %.
- PH value of the water should not be less than 6.
- Compressive strength of Bricks is 3.5 N / mm
- In steel reinforcement binding wire required is 8 kg per MT.
- In soil filling as per IS code, 3 samples should be taken for core cutting test for every 100m2.
- Compressive strength of Bricks is 3.5 N /mm
^{2}. - Maximum Freefall of concrete allowed is 1.50 m.
- In soil filling as per IS code for every 100 sqm, 3 samples for core cutting test should be taken.
- Electrical conduits shall not run in a column.
- Earthwork excavation for basement above 3 m should be stepped form.
- Any backfilling shall be compacted 95% of dry density at the optimum moisture content and in layers, not more than 200mm for filling above structure and 300 mm for no structure.
- If soling is specified the soling stones shall be laid at 45° to 60° inclination (and not vertical) with interstices filled with sand.
- A set of cube tests shall be carried out for each 30 cum of concrete / each level of casting / each batch of cement.
- Water cement ratio for different grades of concrete shall not exceed 0.45 for M20 and above and 0.50 For M10 / M15.
- For concrete grades, M20 and above-approved admixture shall be used as per mix design requirements.
- Cement shall be stored in dry places on a raised platform about 200mm above floor level and 300mm away from walls. Bags to be stacked no more than 10 bags high in such a manner that it is adequately protected from moisture and contamination.
- Samples from fresh concrete shall be taken and at least a set of 6 cubes of 150mm shall be prepared and cured. 3 Cubes each at 7 days and 28 days shall be tested for compressive strength. The test results should be submitted to engineer for approval. If results are unsatisfactory necessary action/rectification/remedial measures has to be exercised.
- Water used for both mixing and curing shall be clean and free from injurious amounts of oils, acids, alkalis, salts, sugar, and organic materials or other substances that may be deleterious to concrete or steel. The ph. shall be generally between 6 and 8.

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