CIVE 202 Study Guide - Final Guide: Ground Granulated Blast-Furnace Slag, Gypsum, Fly Ash

• School: McGill University
• Department: Civil Engineering
• Course: CIVE 202
• Professor: Andrew Boyd

Document Summary

Additional water added to concrete during mixing is detrimental, but applying water during curing is beneficial. Explain the difference between the effects of water addition at these two times and describe what specific point in the microstructure development of the hydration cement paste separates them. Adding additional water during mixing will push cement grains fallen apart, so that they may not be able to interlock and form the cement matrix. Additional water may also create excess voids. Adding water during the set is beneficial, once the cement grains have interconnected, no amount of water will displace them and we want to completely hydrate them. Now we want to add as much water as possible to hydrate the interconnected cement grains. The specific point is when mix starts interlocking. Gypsum (caso4 2h2o) is added during grinding during cement production. Gypsum is added to react with the aluminum phases and prevent a fast set of the cement in concrete.