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What is the Standard for Concrete cube Testing?
The standard for concrete cube testing is to put the cube under increased pressure. The pressure is increased until the cube breaks and determines the cubes compression strength.
How can you calculate the characteristic strength of concrete?
The characteristic strength of the concrete is the compressive strength of the(fck) concrete cubes of size 150 mm tested at 28 days. And compressive strength of cubes should not fall not more than 5% of this fck.
How do you calculate the compressive strength of concrete cubes?
Concrete specimens are tested using the ASTM39 Test Standard Test Methodfor Compressive Strengthof Cylindrical Concrete Specimens by using two samples made from the same test at the same age, usually at strength of 28 days old.Design engineers use the specified strength ƒ´c to design structural elements. This specified strength is incorporated in the job contract documents. The concrete mixture is designed to produce an average strength (ƒ´cr) higher than the specified strength, such that the risk of not complying with the strength specification is minimized.Cylindrical specimensfor acceptance testing should be 6 x 12 inch (150 x 300 mm) size or 4 x 8 inch (100 x 200 mm) when specified. The Concrete strength is calculated by dividing the maximum load at failure by the average cross sectional area.Concrete compressive strength requirements can vary from 2500 psi (17 MPa) for residential concrete to 4000 psi (28 MPa) and higher in commercial structures. Higher strengths up to and exceeding 10,000 psi (70 MPa) are specified for certain applications.Cylinders are placed in a Compression testing machine and loaded to failure from 20 to 50psi. The type of break should be recorded by a Certified Technician.Example 1:For a concrete sample that is broken after 28 daysThe cylinder is 6” diameter, so it has an area of 3.14 x Diameter squared /4A = 3.14 x 6 x 6/4A = 28.26 square inchesIf the force required to break the cylinder was 97,500 poundsThen the compressive strength is 97,500 pounds / 28.26 square inches = 3,450 psi.3,450psi needs to be compared to the Design strength determined by the Design Strength determined by the Design Engineer.Example 2:Given: f 'c = 3000 psiConcrete test cylinders averaged 2800 psi.PSICore 1 =2900Core 2 =2850Core 3 =2450Average compressive strength of 3 cores = 2730 psi.Find: Is the concrete in the structure adequate under CDOT specifications?Solution:Test Evaluation:f 'c = 3000 psiAverage compressive strength of 3 cores - 2730 psiDo any compressive strengths differ from the average by more than 10%?10% of Average compressive strength = 273 psiCore 1: 2900 - 2730 = 170 psi, < 273 therefore OKCore 2: 2850 - 2730 = 120 psi, < 273 therefore OKCore 3: 2730 - 2450 = 280 psi, > 273 therefore -discard core and re-compute average compressive strength using two remaining cores.New average compressive strength = 2875 psi
What is c35 grade concrete in psi?
It is the bearing capacity in N/mm2 when tested on 21 day on a hydraulic testing m/c When we tested this grade concrete cubes on 28th day the compressive strength value have to come 35 N/mm2.
What is one qualitative observation that you make while testing multi cubes?
Meausring them!
What is the minimum number of the smaller cubes required to complete the larger cube?
23 = 8
How do you find the surface of the cube?
Use the information you're given, in conjunction with the properties of cubes, to find the required quantity.
What has the author H C Erntroy written?
H. C Erntroy has written: 'The variation of works test cubes' -- subject(s): Concrete, Testing
Why the size of concrete cubes are 150mm?
Basically, the force supplied by a concrete compression machine is a definite value. For normal concrete strength application, say below 50MPa, the stress produced by a 150mmx150mmx150mm cube is sufficient for the machine to crush the concrete sample. However, if the designed concrete strength is 100MPa, under the same force (about 2,000kN) supplied by the machine, the stress under a 150mmx150mmx150mm cube is not sufficient to crush the concrete cube. Therefore, 100mmx100mmx100mm concrete cubes are used instead to increase the applied stress to crush the concrete cubes. For normal concrete strength, the cube size of 150mmx150mmx150mm is already sufficient for the crushing strength of the machine.
If one sugar cube has an edge that is 1.2 cm in length how many sugar cubes are required to carpet 1500 square feet?
To find the number of sugar cubes required to carpet an area, you need to determine the area covered by each sugar cube. If a sugar cube has an edge length of 1.2 cm, its surface area is 6.48 square cm. Convert 1500 square feet to square cm and then divide by 6.48 to get the number of sugar cubes needed.
How many cubes having 2 cm edge will be required to make a cube having 4cm edge?
You would need 8 smaller cubes with 2 cm edge to form a larger cube with a 4 cm edge.
HOW MANY CUBes if you have 3 rows of 3 cubes?
3 cubes x 3 rows = 9 cubes
