Part 5 - Water Quality

"If you can drink it, you can make concrete with it." However, good quality concrete can be made with water that would not pass drinking water standards. Hence, there is no ASTM standard for water quality. However, mixing water can introduce impurities that could have negative effects on concrete. Water with large quantities of suspended solids, dissolved solids, or organic material should not be used.

• Suspended Solids -- High amounts of solids can increase water demand, increase dry shrinkage, cause efflorescence (excessive leaching of salts which increases porosity and decrease strength), and affect air-entraining.
  
• Dissolved Solids -- A variety of dissolved salts can cause many problems from slower setting and hardening times to reduced strength. The use of seawater can lead to high early strengths, but lower 28-day strengths. This is due to high amounts of sulfate, which cause increased crystallization of ettringite. High amounts of chloride increase the risk of corrosion of reinforcing bars. Therefore, this should not be used for prestressed concrete.
  
• Organic Material -- Many organic waters from industrial wastes retard hydration and entrain excessive amounts of air into the concrete. Some waste waters are used to produce just such set-retarding or air-entraining admixture effects.

ASTM Testing of Water

There are no ASTM standards for water. However, there are two methods for determining the suitability of water. They involve comparing setting times and compressive strengths from concretes made with the water in question and distilled water. A water is considered suitable if the setting time does not differ by more than 30 minutes and the strength is not reduced by more than 20% when compared with a sample using distilled water.

This website was originally developed by Charles Camp for his CIVL 1101 class.
This site is maintained by the Department of Civil Engineering at the University of Memphis.
Your comments and questions are more than welcome.