An Exercise in Freezing Point Depression

B. The Corrosive Effects of Deicers on Concrete and Iron Surfaces During RepeatedFreeze - Thaw CyclesConcrete scaling refers to damage done to concrete surfaces under various conditions. Theamount of scaling is rated from 1 to 5, with 1 being no surface damage during the studyand 5 being the most significant damage.Two sets of concrete samples were prepared in plastic containers. One set consists ofconcrete in 1300 mL beakers. In the second set, the concrete samples were placed in 800mL containers and a U – shaped iron bar was imbedded in the concrete. Each concretesample was covered with one of 9 different solutions and was then subjected to 10 freezethawcycles between about -17°C and room temperature. Because of the time required toprepare the concrete samples and to put them through a number of freeze – thaw cycles,the samples were prepared and treated outside of the regular laboratory and over aperiod of several weeks. The resulting concrete samples will be on display during the twoweeks spent on Experiment 10.1. Examine the concrete samples which have no iron bars present, estimate theamount of scaling on each sample and report the results, which will be subjective,on Data Sheet IIB.Do not touch the concrete surfaces!2. Also describe the extent of corrosion on the U – shaped bars on a scale of 1 to 5 andreport the results on Data Sheet IIB. Once again the results, while reported to thebest of your ability, are qualitative. For a given deicer, did the presence of the ironbar affect the amount of scaling on the concrete surface?3. Look around campus and around town for places where rusty iron bars and flakedconcrete reveal damage to bridges, parking ramps, roadways, etc. (Hint: A photoof serious rust or crumbling concrete, with the location noted, would be a goodaddition to your lab report or to a poster on deicers.10-8