The properties of cement concrete is very wide subject, here is a brief discussion on the topic. The most important properties of fresh and hardened cement concrete are: Workability, Compressive and tensile strength and durability. As desirable properties of concrete in fresh and hardened states often bring conflicting requirements in materials and mix proportion, the aim of rational mixed design is to reconcile these factors. Workability Workability is defined as the ease with which freshly mixed concrete is placed compacted and finished. It is the most desirable property of fresh concrete. Optimum workability of concrete varies from situation to situation and concrete which can be termed as workable for laying into a large section with minimum reinforcement may not be equally workable for laying in thin section with heavy reinforcement. A concrete may not be workable when compacted by hand but may be satisfactory when mechanical vibration is used.
Compressive Strength Compressive strength is the most important property of hardened concrete. It can be measured easily with standard size cube 15 centimeter or cylindrical specimens and is often taken as in index of overall quality of concrete. Many other desirable properties of concrete, such as shear and tensile strength, modulus of elasticity, bond strength, impact and abrasion resistance and durability etc. are related to compressive strength. Water cement ratio, size of aggregate and aggregate cement ratio are most important factors for compressive strength.
Durability of Concrete A durable concrete is one that performs satisfactory in working environment during its anticipated exposure conditions during the service. The materials and mix proportion specified and used should be such as to maintain its integrity and if mild steel embedded in the concrete i.e. in case of R.C.C it should be protect the mild steel from corrosion. Durability of the concrete is the resistances to deteriorate influences which may by inadvertence or ignorance reside inside the concrete, or which are inherent to the environment to which the concrete is exposed. Under normal circumstances concrete is durable, Every batch of the concrete is designed to serve long life of R.C.C. Problems arise when concrete contains ingredients which were not known before hand to be deleterious, or when they are exposed to harmful environments not anticipated earlier.