Concrete

Pre-reading activities Post- Activities Definitions:
 * Concrete:** Is a manufactured mixture of cement and water, with aggregates of sand and stones, which hardens rapidly by chemical combination to a stonelike, water-and-fire-resisting solid of great compressive but low tensile strength.
 * Reinforced concrete:** Was developed to add the tensile strength of steel to the compressive strength of mass concrete.


 * concrete-shell construction:** Shell reduced that the thickness is comparatively less than that of an eggshell.
 * Precast- concrete construction:** that employs bricks, slabs, and supports made under optimal factory conditions to increase waterproofing and solidity, to decrease time and cost in erection, and to reduce expansion and contractions.
 * Prestressed concrete:** provides bearing members into which reinforcement is set under tension to produce a live force to resist a particular load.