How to Calculate Concrete Compressive Strength from ASTM C 39 Data - Vlog 656

[@macdedeh69]

i completely understood. thankyou dear

[@bkjeppsen]

Excellent Presentation: Can you help me understand why the latest (2020) version of ASTM C39 changed the calculation formula from using the standard cross-sectional area of the cylinder (as described above) to muliplying the applied force by 4 and then dividing by the pi x DIAMETER of the cylinder squared?

[@IntelligentConcrete]

HEY HEY BRIAN!!! I didn't know about the change more than likely its due to the fact that we measure Diameter of the cylinder and not radius.

[@robertoreyes3588]

Pretty nice explanation easy and fast love it can you guys do a video about unit. Weight explain it so some people can understand more what it is ? Please

[@IntelligentConcrete]

Thanks and can do!!!

[@stanjames4548]

isnt it the compressive strength is calculated by the bigger area of the cylinder? the diameter x height?

[@IntelligentConcrete]

No Sir. P = F / A. Pressure = Force divided by area of the applied load.

[@stanjames4548]

@@IntelligentConcrete oh surely i know its §=P/A, what i mean is the area(A) use to calculate the compressive strength, isn't the diameter x height?

[@IntelligentConcrete]

@@stanjames4548 no. That is when you are doing Splitting tensile strength.

[@adriengignoux813]

oh my god what are those units

[@IntelligentConcrete]

Howdy Adrien, those are common units to express compressive, flexural, and tensile strength of materials in the US. Across the big blue pond folks normally use MPa. For a frame of reference, there is 145 psi for every 1 MPa.

[@TheOnion619]

Such an absolute cutie!

[@ahmet9719]

A solid object with width, length and height(thickness) of 15x15x(15) cube is placed in a hydraulic press. It breaks with a load of 300 kN. At what load would 15x15x(2) object made of the exact same material break? please don't say "at same load" we know the second one is broken easier than first one. because it must be this way. because it is thinner. i searched all the internet, couldn't find it. is there a formula of this? If you are going to say "it will break "at the same load"", despite everything, please convince me.

[@IntelligentConcrete]

@@ahmet9719 ASTM C 42 - gives correction factors for shorter samples.

[@ahmet9719]

@@IntelligentConcrete could you please elaborate that article? I am not an english man. I read it but couldn't understand.

[@IntelligentConcrete]

@@ahmet9719 In ASTM C 42, the "strength correction factor" is a numerical value applied to the compressive strength of a concrete core to account for the variation in strength based on its length-to-diameter (L/D) ratio, essentially correcting for the observed phenomenon where cores with a smaller L/D ratio tend to exhibit a lower measured strength compared to cores with a more ideal L/D ratio, typically considered to be around 2:1; this means that if a core has a significantly different L/D ratio, the measured strength needs to be adjusted to reflect a more accurate representation of the concrete's true strength.