durability? Compared to other considerations, how much importance should be given to durability in the design and construction of concrete structures?...

1) What do you understand by the term durability? Compared to other considerations,how much importance should be given to durability in the design and construction ofconcrete structures?2) How would you define the coefficient of permeability? Give typical values of thecoefficient for (a) fresh cement pastes; (b) hardened cement pastes; (c) commonly usedaggregates; (d) high-strength concretes; and (e) mass concrete for dams.3) How does aggregate size influence the coefficient of permeability of concrete? Listother factors that determine the permeability of concrete in a structure.4) With respect to frost damage, what do you understand by the term critical aggregatesize? What factors govern it?5) Discuss the factors that influence the compressive strength of concrete exposed to afire of medium intensity 650 C, short-duration exposure). Compared to the compressivestrength, how would the elastic modulus be affected, and why?6) List some of the common sources of sulfate ions in natural and industrialenvironments. For a given sulfate concentration, explain which of the following solutionswould be the most deleterious and which would be the least deleterious to a permeableconcrete containing a high-C3A portland cement: Na2SO4, MgSO4, CaSO4.7) What chemical reactions are generally involved in sulfate attack on concrete? Whatare the physical manifestations of these reactions?8) What is the alkali-aggregate reaction? List some of the rock types that are vulnerableto attack by alkaline solutions. Discuss the effect of aggregate size on the phenomenon.9) With respect to the corrosion of steel in concrete, explain the significance of thefollowing terms: carbonation of concrete, passivity of steel, electrical resistivity ofconcrete, state of oxidation of iron.10) Briefly describe the measures that should be considered for the control of corrosionof embedded steel in concrete.