CONCRETE STRUCTURES
CONCRETE STRUCTURES 
DEFINTITONS: ============ CEMENT: A binder such as Portland Cement which binds aggregates into a hard concrete or mortar within a few days. CONCRETE: An intimate mixture of water cement aggregates admixtures History of Cement and Concrete: ========================= Egyptian Pyramids burnt gypsum 4000 B.C. sun-dried brick 2500 B.C. sand and gypsum mortar Roman Quicklime (burnt lime stone) Coliseum in Rome Basilica of Constantine 500 B.C. lime and sand mortar 300 B.C. volcanic ash (pozzolan) added 100 B.C. ground potter used instead of volcanic ash 10 B.C. Vitruvius a military engineer established 1:3 lime to sand ratio Middle Ages 11th century - inferior lime 1290 "mortar" appeared in Oxford English Dictionary 14th century pozzolan - lime from Italy 1757-59 Eddystone Lighthouse John Smeaton blue lias - clay limestone from Plymouth terra puzzolano - limestone from Italy Rhenish trass - used in Holland 18th Century France Lesage & Vicat England Frost & Parker experiment with cementing agents burning natural mixtures of lime and clay 1811 Roman Cement James Parker - patent hydraulic cement (hardens under water) Isles of Sheppey 1818 Ralph Dodd patent for wrought-iron bars in concrete 1824 Joseph Aspdin brickmason from Leeds,England patent Porland Cement resemble limestone quarried near Portland 1850 Cement Industry well established in Belgium England Germany 1861 Joseph Monier Parisian gardener iron mesh reinforcement for flower tubs 1867 Paris Exhibition Monier & Coignet containers, pipes, railroad sleepers 1868 First Cement Shipments to the USA 1871 David Saylor Copley, Pennsylvania first portland cement produced in USA 1875 Reinforced Concrete in USA 1895 USA Cement Industry well under way 1912 Precast Concrete 1918 Duff Adams quality of concrete decreases as the water-cement ratio goes up 1925 Ready-Mix Industry well established 1928 High-frequency vibrators use of relatively dry, harsh mixes 1930 Hoover Dam low-heat cement for mass concrete 1930's Air-entrainment research 1940 Paddle Mixer 1941 Low-alkali cement deterioration as aggregates and cement react 1960 Concrete Pump 1970 Superplasticzer 1988 Silo Mortar Systems first time in the USA
