### Discussion :: Concrete Technology - Section 1 (Q.No.14)

P.Vamsi said: (Sep 22, 2013) | |

Grade of cement tells about strength of concrete. |

Sandip said: (Sep 27, 2013) | |

The grade represents the compressive strength. |

Manoj said: (Oct 26, 2013) | |

We know that in M20, M stand to mix and 20 is the characteristic compressive strength of concrete, so as in this Q. 300 is the right answer. |

Anil Reddy said: (Jan 12, 2014) | |

M300 in in kg/cm2. We convert this to N/mm2. 1kg = 9.8N nearly 10N. M300kg/cm2 = M300*10N/(10*10MM2) = M30N/MM2. For M30 we know 30N/mm2 i.e 300kg/cm2. |

Shubham said: (Sep 14, 2014) | |

M300 in in kg/cm2. We convert this to N/mm2. 1kg = 9.8N nearly 10N. M300kg/cm2 = M300*10N/(10*10MM2) = M30N/MM2. For M30 we know 30N/mm2 i.e 300kg/cm2. But,in question asking for permissible comp strength. So, to obtained it divide by 3(factor's of safety for concrete)hence 100kg/cm2 is the right answer. |

Rahul said: (Sep 29, 2014) | |

It tells about the "characteristic compressive strength" @Sandeep. |

Jitesh said: (Jul 3, 2015) | |

M300 grade of concrete which is in kg/m2. When we convert it in n/mm2 we get m30. That is its strength is 30n\mm2. |

Kulendra said: (Jul 8, 2015) | |

But ask about Permissible compressive strength of concrete. |

Tony said: (Aug 9, 2015) | |

Instead if kg/cm^2 they should have mentioned n/mm^2. |

Gyanu said: (Sep 28, 2015) | |

Where is used M300? |

R Subramanian said: (Mar 21, 2016) | |

As per latest technology M200 and M400 grade of concrete is using in other country like Canada and New Zealand. |

Debiprasad Mukherjee said: (Jul 19, 2016) | |

All the answer value and unit is wrong. |

Snehal Wankhede said: (Sep 1, 2016) | |

Permissible compressive stress in concrete = 0.33 fck = 100 kg/cm^2. |

Duraisamy said: (Apr 7, 2017) | |

m15-compressive strength 15n/mm2 in maximum. 1N = 100g. m20-20N/mm2. m30-30N/mm2. |

Vijay Kumar Singh said: (Apr 17, 2017) | |

M 25 grade of concrete the comprehensive strength is 350 to 400 kg/cm^2 is ok or not? |

Chetan said: (Aug 23, 2017) | |

Wrong answer, according to question, The permissible compressive strength is required not characteristics compressive strength. So, direct permissible compressive strength is 75N/mm^2. And for bending com str is 96N/mm^2. |

Thet said: (Nov 11, 2017) | |

I want to know concrete grade number for 240 kg/cm2. |

Sachin Kumar said: (Aug 21, 2019) | |

100 N/mm2 is the right answer. |

Bindu said: (Oct 13, 2019) | |

The permissible compressive strength of M30 is 11.5. |

Shashank Sharma said: (Feb 21, 2020) | |

Since here, it asked for the permissible stress of concrete in bending compression and in WSM we know that for finding the permissible stress we divide it by 3 (i.e. FOS for concrete) in WSM so after dividing. 300 kg/cm ^{2} รท 3 = 100 kg/cm^{2} should be the answer. |

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