Name:_____________________ Homework 1 Question 1 a) What are the two basic raw materials used for the manufacture of portland cement? b) Which of the four major compounds contributes most to the strength development during the first few weeks of hydration? c) What is the main difference in compound composition of an ordinary Type I and a high early strength Type III portland cement d) What type of cement (I to V) would one use in (I) cold-weather construction, (II) a dam, (III) sewer tank For each cement indicate its principle characteristics. e) What type of cements would you recommend for concretes required in the following environments and why?: (a) North pole (b) San Francisco harbor f) Comparing the composition of a Type II cement with that of a Type I cement indicate which of the four major compounds would be present in a larger amount and which in a lower amount. Explain why. Question 2 I) Define hydraulic cement and give one example of a non-hydraulic cement. II) Give two advantages and two disadvantages of having cements with high C3A content. III) In the older times the cement raw materials were transported by water (“wet-process”). Explain why this method is not used anymore. IV) What are the advantages and disadvantages of using calcium aluminate cements? Question 3(midterm 2004) I) Give the approximate dimensions for the following: (8 points) Cement particle: Silica fume: Sand grain Air-entrained air voids:II) The architect wants to build a concrete structure that has lighter shades of gray. Which cement should you use? (3 points) Cement A: C3S=50 %, C2S= 25 %, C3A = 5%, C4AF = 20% Cement B: C3S= 55%, C2S = 25%, C3A = 10%, C4AF = 10% III) Describe the hydration reaction that generates the most heat. (3 points) IV) Describe Type IV cement. Why is it not available in the market anymore? (3 points) Question 4 I) A portland cement has the following composition: 60% C3S, 15% C2S, 13% C3A, 12% C4AF: a) will the cement give high early strength? b) Will the cement generate high heat of hydration? c) In what type of construction you should not use this type of cement? II) What do you know about the composition and principal characteristics of the following cement types: Type IS cement, calcium aluminate cement. Question 5(Midterm Spring 2005) I) You’re the manager of a cement plant and observed that the construction market is demanding a cement that gives high-early strength. In order to be competitive you decide to grind the cement very fine. List the potential problems that this cement may cause when used in concrete structures ? (6 points) II) Assume that you were able to keep your job as the manager of the cement plant. Your geologist suggests to use raw materials that do not contain iron nor aluminum so the cement will not have C3A nor C4AF. Is this a good idea? Question 6 (Midterm Spring 2012) I) The compositions of commercially available Type I and type III Portland cements are often very similar. If so, what is the reason for Type III to provide consistent high early strength? II) What temperature is typically reached in the hottest part of the cement
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