Introduction to Concrete and Masonry Ag III and IV
It’s pretty much everywhere. • Work in groups of 3. • In the next four minutes, list a different item made from concrete for each letter of the alphabet. • Example: A=Apple red fire hydrants
Today’s objectives • Define concrete • Name rules for making quality concrete • List ingredients in concrete • Identify properties of concrete
What is concrete? • One of the most widely used building materials in the world • No other building material in which the final product depends so much upon the user than concrete • It’s everywhere • Share your lists!
It’s going to be around for a while • Easy mixing process yields a product that weighs 150-160 lbs per cubic foot. • Components of concrete: water, cement, and aggregate, are plentiful • Requires little energy for production and use • Qualities that give concrete appeal are going to still be important down the road: • Strength • Versatility • Durability • Fire resistance
Rules for making concrete • Use proper ingredients • Proportion ingredients correctly • Accurately measure the ingredients • Mix the ingredients thoroughly • Follow proper finishing and curing methods
So what are the ingredients? (And how do they work?) • Portland Cement • Aggregate • Water • Portland and water forms a paste around each piece of aggregate • Changes from a plastic state to a hardened state • It’s not drying! It’s a chemical change. (Think release of heat.)
Properties of “plastic” concrete • Consistency (or slump)- wetness or dryness of the mix • Uniformity- thorough mixing of ingredients • Workability- ease with which it can be placed and consolidated
Properties of hardened concrete • Each person is receiving an index card. • Match the correct word with the definition. • Take your seats, so I’ll know you’re done.
Today’s objectives • Identify properties of concrete • Name rules for making quality concrete • List ingredients in concrete • Discuss the difference between cement and concrete