(h) The lower the water- cement ratio, the more durable the con- 

 crete will be in salt water. 



(i) Coarse and fine aggregates must be selected carefully for 

 density of gradin, and to avoid unfavorable chemical reaction with the 

 cement. 



(j) Maintenance of enough concrete cover over all reinforcing 

 steel during casting is very important. 



(k) Smooth form work and rounded corners improve the durability 

 of concrete structures. 



(1) Steel in and above the tidal range will last longer if pro- 

 tected by coatings of concrete, corrosion-resistant metals or organic and 

 inorganic paints (epoxies, vinyls, phenolics, etc). 



6-99 



