Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Concrete and Tensile Strength
Name: Abhishek
Status: student
Grade: other
Location: N/A



Question:
It is a fact that tensile strength of concrete is about 10% of its compressive strength!! Why do concrete members have such a weak tensile strength?


Replies:
Abhishek,

The requirements for tensile strength is that the molecules or atoms hold together when being pulled apart. If the material has many grain boundaries or cracks, then the material pulls apart easily.

The requirements for compression resistance is for the atoms and molecules not to slip past each other. As long as the grains remain in place, then the material can resist compression without necessarily having tensile strength.

Greg (Roberto Gregorius)


Concrete is a brittle substance. You can push on it hard and it is strong. But if you try to "stretch" it, it fractures. That is one of the reasons that steel reinforcing bars are used in concrete construction and also why concrete used in road paving has "expansion" grooves. It is hard but does not withstand "stretching" forces, such as the freezing of water.

Vince Calder



Click here to return to the Material Science Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory