Portland Cements I. Types of Cements 1. pozzolana and pozzolanic cements ( 火山灰水泥） 2. blastfurnace slag cements （炉渣水泥） 3. high-alumina cements ( 高矾土水泥） 4. special cements such as white, colored, waterproofed, masonry, oil-well, and expansive cements 5. Portland cement: common calcium silicate cement II. *Portland Cements 1. History: In 1824, Aspdin, a British stone mason, invented a cement which he named portland cement because it resembled a stone quarried on the Isle of Portland off the British Coast. 1 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements II. Portland Cements 2. Raw and processed materials: calcareous materials like limestone and marl and argillaceous substances like clay and shale, with major mineral ingredients of calcium, silicon, aluminum, and iron. 3. Constituents: tricalcium silicate (3CaOSiO 2 or C 3 S), dicalcium silicate (2CaOSiO 2 or C 2 S), tricalcium aluminate (3CaOAl 2 O 3 or C 3 A), and tetracalcium alumino ferrite (4CaOAl 2 O 3 Fe 2 O 3 or C 4 AF) 4. *Manufacturing Process:Manufacturing Process: 1) Producing a cement that meets specific chemical and physical specifications requires careful control of the manufacturing process. 2 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements II. Portland Cements 4. Manufacturing Process: 2) Breakdown process (1) obtaining raw materials which are reduced by primary and secondary crushers to 5-inch size (125-mm), then to 3/4-inch(19 mm); (2) proportioning the materials at the cement plant to create a cement with a specific chemical composition with two different methods, dry and wet;dry and wet (3) Completing the grinding and blending operations for the materials in slurry form; 3 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements (4) after blending, feeding the mixture of raw materials into the upper end of a tilted rotating, cylindrical kiln; (5) forcing burning fuel consisting of powdered coal or natural gas into the lower end of the kiln; (6) heating the raw materials to very high temperature, and at 2700ºF (1480º C), a series of chemical reactions causing the materials to fuse and creating cement clinker—grayish-black pellets, often the size of marbles; (7) Discharging the clinker red-hot from the lower end of the kiln and then transferring it to various types of coolers to lower the clinker to handling temperatures; 4 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements (8) Combining the clinker with gypsum and grinding the mixture to pass through a No. 200 mesh sieve; (9) Packing and storing the gray powder—portland cement 5. Types of Portland Cements According to AASHTO and ASTM specifications, eight types of portland cements are listed as follows:  Type I: a normal, general-purpose cement suitable for all uses - used where the special properties of other types are not required; - used where cement or concrete is not subject to specific exposures, such as sulfate attack, or to an objectionable temperature rise due to heat generated by hydration. 5 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements -uses including pavements and sidewalks, reinforced concrete buildings, bridges, railway structures, tanks, reservoirs, culverts, sewers, water pipes and masonry units  Type IA: similar to Type I with the addition of air-entraining properties only air-entraining  Type II: generating less heat at a slower rate and with a moderate resistance to sulfate attack -used where precaution against moderate sulfate attack is important, as in drainage structures where sulfate concentrations in groundwaters are higher than normal but not unusually severe - usu. generating less heat at a slower rate than Type I 6 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements -used in structures of considerable mass, such as large piers, heavy abutments, and heavy retaining walls, especially when the concrete is placed in warm weather.  Type IIA: identical to Type II with the addition of air-entraining properties  Type III: a high-early-strength cement, chemically and physically similar to Type I, except that its particles have been ground finer. -providing high strengths at an early period, usually a week or less -used when forms are to be removed as soon as possible, or when the structure must be put into service quickly, especially in cold weather. 7 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements  Type IIIA: an air-entraining, high-early-strength cement  Type IV: with a low heat of hydration and developing strength at a slower rate than other cement types, making it ideal for use in dams and other massive concrete structures where there is little chance for heat to escape  Type V: sulfate-resisting, used only in concrete structures that will be exposed to severe sulfate action, principally where concrete is exposed to soil and groundwater with a high sulfate content. 8 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements 6. Tests on specifications of cement 1) Chemical test: a chemical analysis of the proper quantity of strength-giving compounds; 2) Physical test: fineness, stability, time of set, air content, and compressive strengths of mortars made using Ottawa sand III. Homework 1. The manufacturing process of Portland cement. 2. Ex. IV on page 43 in the main text book. 9 Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015Monday, October 05, 2015

Portland Cements 1.In the dry process, dry raw materials are proportioned, ground to a powder, blended together and fed to the kiln in a dry state. 2.In the wet process, a slurry is formed by adding water to the properly proportioned raw materials. Back 10 Monday, October 05, 2015

Portland Cements Specifications for air-entraining cements Types IA, IIA, and IIIA correspond in composition to ASTM Types I, II, and III, respectively, except that small quantities of air-entraining materials are interground with the clinker during manufacture to produce minute, well-distributed, and completely separated air bubbles. These cements produce concrete with improved resistance to freeze-thaw action. Back 11 1 November 2004