1. Estimate the amount of Ca(OH)2(s) leached from concrete during a one-year period by precipitation. Assume that the area receives 40 in/yr of precipitation which is in equilibrium with PCO2= 10^-3.5 atm and [SO42-] = 10^-4 M. Assume that: a. The rain and concrete reach equilibrium rapidly. b. The remaining chemistry of the concrete does not impact leaching of Ca(OH)2(s). c. Within the concrete, assume a closed system with CT in solution equal to that in the incoming precipitation.
2. Assume that the primary driver for oxygen to rebar in concrete is rainwater. a. For the same climate conditions in problem 1, estimate the mass of rust formation for rebar during a year in concrete if the [O2] is 8 mg/L. Assume complete reaction. 2Fe + 3/2 O2= Fe2O3 b. Is this a reasonable estimate? Explain.