How important is the compressive strength of polymer concrete?

Polymer concrete is known for having robust material properties.  Both compressive and tensile properties of polymer concrete will typically exceed those of a standard Portland cement concrete.  Along with it’s corrosion resistance, this make polymer concrete an ideal material for use in corrosive environments.  How these properties are utilized in the design of a precast structure is an important part of determining the overall influence of the design.  Polymer concrete has a much higher tensile strength than Portland cement concrete.  It can be four times as great in some cases.  This sounds great, with a higher tensile strength, the need for reinforcement can reduced, right?  Not so fast.  Polymer concrete has a great tensile property when it is young.  However, over time, the tensile property can lose 20% of it’s original capacity.  It’s important to note that it’s the tensile property in all concrete designs that needs to be supplemented with reinforcement.  Polymer concrete is no different.  It should be noted that polymer concrete fails in a brittle mode which would give little to no visual warning to the naked eye.  The property which gets the most attention is compressive strength.  Polymer concrete compressive strengths can range between 9,000-16,000 psi.  This seems like a very impressive number, and it is.  While both tensile and shear properties are a function of the compressive strength, they are both limited in their application and values.  The biggest role compressive strength plays in the design is the stress block area.  For purely compressive stresses, a very high compressive strength would have a significant impact on reduction the required section thickness.  However, once the need for moment and shear capacity are encountered, dynamics change.  So the compressive strength is impressive on a properties sheet that is used for marketing and it does add to the overall toughness.  When it comes to the capacity design, the ultra-high compressive strength doesn’t provide as much as one would think.