Contents
Why a strain controlled test is preferred over a stress controlled test?
The advantage of the strain-controlled tests is that, for example for dense sand, peak shear resistance (at failure) as well as lesser shear resistance (at a point after failure so-called ultimate strength) can be observed and plotted. In stress controlled tests, only peak shear resistance can be observed and plotted.
What is the purpose of the compressive testing of concrete?
The results from the compressive strength test are used to determine the strength of the concrete. If the test results are inconclusive or show that your concrete isn’t curing as quickly as it should, you risk not being able to advance your project as soon as you would like to.
Why is compressive strength test important?
Compressive strength is one of the most important properties of concrete and mortar. The strength of the binder (cement) therefore has a significant effect on the performance characteristics of the mixture and ensures the overall quality of the finished product.
Why is compressive strength usually considered being most important in concrete design?
Compressive strength can be defined as the capacity of concrete to withstand loads before failure. Of the many tests applied to the concrete, the compressive strength test is the most important, as it gives an idea about the characteristics of the concrete.
What is strain controlled loading?
Strain controlled and displacement controlled tests are identical in that the rate of travel during the test is maintained constant throughout the test and the load required is measured; opposite the load test in which a uniform rate applied loading and the displacement is measured.
What is strain control test?
In the strain controlled tests, one can control the total strain or plastic strain. The creep component also becomes important depending on the ratio of the test temperature to the material melting point.
What is the compressive strength of concrete?
The compressive strength of concrete ranges from 15 MPa (2200 psi) to 30 MPa (4400 psi) for residential concrete and is high in commercial structures. Some applications use forces greater than 10,000 psi (70 MPa).
How is concrete tested for strength?
Compressive strength of concrete Compressive strength is tested by breaking cylindrical concrete specimens in a special machine designed to measure this type of strength. It is measured in pounds per square inch (psi). Testing is done according to the ASTM (American Society for Testing & Materials) standard C39.
What is the normal range of compressive strength for concrete?
2,500 to 5,000 psi
While traditional concrete normally has a compressive strength ranging anywhere from 2,500 to 5,000 psi, UHPC can have a compressive strength of up to 10 times that of traditional concrete.
What does strain control mean?
In a STRAIN CONTROLLED test, the test is conducted in such a way that the strain increases at a given rate. Generally the specimen is tested at a uniform strain rate. Since we know the strain in the specimen in any stage of testing we require the magnitude of stress to plot the curve.