What are the impact of organic impurities (Water) on concrete?

Besides reactive minerals, aggregates may contain other impurities, such as organic matter, which are harmful to concrete.

Organic matter derived from decaying vegetation, that delay setting and hardening of concrete & found in fine than in coarse aggregate and

Normally, the strength of concrete based on sand is used as a gauge of the harmful effects of the impurities.

Silt, clay and dust may form a coating on aggregate particles, resulting in weakened bond between the aggregate and the cement paste.

Almost any natural water that is drinkable and has no pronounced taste or odor can be used as mixing water for making concrete.