How to test steel reinforcement in construction site.

TESTING OF STEEL REINFORCEMENT IN CONSTRUCTION SITE

Steel is the backbone of every construction industry. Good quality and best grade of steel reinforcement is the ultimate target for any site managers. The strength and durability of a structure depends fully on good quality steel. No compromise on steel quality. To check the quality, we need to test it at every consignment.

There are basically two types of steel reinforcement testing are done for construction work. One is the physical test, and another is the chemical composition test. Each construction site has a lab for testing of concrete cubes, coarse and fine aggregates etc. but chemical test for steel needs a separate setup and expertise. So, most of the site do chemical test from outside agency. And, physical test is carried out at site.

PHYSICAL TEST:

Physical tests can be done in any construction site with minimum effort. It needs only weighing machine, cutting tool, Vernier scale etc. In physical test of reinforcement, the followings are checked.

Unit weight of bar: To check the unit weight, cut the bar exact 1m length 3 nos. and weight it on weighing machine separately and compare it with the standard weight. During manufacturing process some manufacturing defects may occur which may cause under dia. Bar or over dia. Bar, but it should be within the tolerance limit prescribed in the I.S – 1852: 1985. The I.S.Code refers the following tolerance of weight for different dia. of bar in percentage terms.

·         Weight tolerance for dia. Up to 10 mm bars --------------- +/- 7%

·         Weight tolerance for dia. above 10 to 16 mm bars ------- +/- 5%

·         Weight tolerance for dia. above 16 mm bars --------------- +/- 3%

Dia. Of bar: The tolerances on size and dia. of bar shall be +/- 0.5 mm and this can be checked by Vernier scale.

Surface defects: Finished material shall be free from Rusting, cracks, surface flaws, laminations,

rough, jagged and imperfect edges, etc.

CHEMICAL COMPOSITION TEST:

In chemical composition test for reinforcement bars mainly three elements are checked. The Carbon, Sulphur and Phosphorus. Percentage of these elements should not exceed the maximum limit as per I.S – 961: 1975 given below:

Carbon – 0.27%

Sulphur – 0.055%

Phosphorus – 0.055%

The mechanical properties like tensile and compressive strength are also tested in chemical lab.

Steel suppliers also provides chemical test report with their invoices of their own, but reliability is the concern. So, we need to do chemical test of reinforcement and compare it with the suppliers one. If any discrepancy found, the consignment should be stopped.

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Hi, I’m Gobinda Burman (Green Environment). More than 27 years in the field of Building Construction industry, I’ve completed many high-rise building projects successfully. I have got the opportunity to learn and solve the critical practical problems related to building construction. I love to share my knowledge with those people who wants to build their own home and the budding civil engineers willing to build their career in this field..

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