INTRODUCTION

The purpose of this lab is to test the strength properties of concrete that has been moist cured for fourteen days. Tensile, flexural and compression strength are looked at as well as non-destructive tests.

Concrete testing is conducted to evaluate laboratory mixtures of concrete mix design, quality control for in-place concrete and determining when construction forms may be removed. The compressive strength of concrete is usually specified because it is an easily obtained parameter and can be directly related to other physical and durability parameter. Flexural and tensile strengths can be estimated from the compressive strength value. The Schmidt-Hammer test is a non-destructible test of the surface hardness of concrete. It measures the rebound of a spring-loaded plunger after it has struck a smooth concrete surface, which gives an indication of the compressive strength of concrete.

All testing of hardened concrete needs to be done in accordance with ASTM standards and needs to fall under the building code requirements in order to be used for construction.

Unit weight (density) of concrete varies depending on the amount and relative density of the aggregate. The modulus of elasticity is found from the slope on the stress vs. strain curve.