Civil Engineering

 Blog By Er. Navneet Kumar Sampling of Concrete Cubes for Test -As per IS 516-1959 Size of Test Specimens -  Test specimen cubical in shape shall be 15 X 15 X 15 Cm. If the largest nominal size of the aggregate does not exceed 2 cm.  10 cm cubes may be used as an alternative.  Cylindrical test specimens shall have a length equal to twice the diameter. They shall be 15 Cm in diameter and 30 cm long. Cube Moulds- The cube mould shall be of  metal, preferably steel or cast iron, and stout enough to prevent distortion.  The height of the mould and the distance between opposite faces shall be the specified  size + 0·2 mm.  The angle between adjacent internal face and between internal faces and top and bottom planes of the mould shall be 90° + 0.5°. The interior faces of the mould shall be plane surfaces with a permissible variation of 0·03 mm.  The base plate shall be of such dimensions as to support the mould during the filling without le...

Blog By Er. Navneet Kumar What is characteristic strength of concrete in flexure ?  👉Characteristic strength of concrete is the value of strength of concrete below which not more than  5 % of test results are expected to fail.               It is denoted by fck.                                                           fck = fm- 1.65σ        Where fm= Target mean strength & σ = standard deviation. Note- 👉Concrete is designated by characteristic cube strength of concrete at 28 days. 👉No material is truly homogeneous , so strength of similar concrete varies in different testing. 👉For most of the engineering materials ,probability is symmetrical about mean and such a curve is called Normal Probability distribution curve.               ...