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Quality of water curing concrete specimens in water tanks

Quality of water curing concrete specimens in water tanks

(OP)
Hi
I have noticed that my firm uses contaminated water for the curing of concrete specimens in water tanks. The water is unusually greenish with organic matter such as larvae or whatever that heck it is . So does it affect the compressive strength in any way ? i am searching the net for something like that but i can barely find anything in this regard

RE: Quality of water curing concrete specimens in water tanks

You firm should probably be using potable water to avoid contamination.

RE: Quality of water curing concrete specimens in water tanks

(OP)
I think contamination developed over time due to exposure to the air , and water hasn't been recycled over months but the question is does it have any significant effect ? what if the water contains sulfates for instance

RE: Quality of water curing concrete specimens in water tanks

RE: Quality of water curing concrete specimens in water tanks

its recommended (by ASTM STP 169B) that curing water not stain and not have aggressive agents that can attack the concrete. if you have not tested your curing water quality, than you cannot confirm that. you should stick to water that meets the mixing water quality requirements (ASTM C94).

RE: Quality of water curing concrete specimens in water tanks

(OP)
i think my query hasn't been well understood so let me clarify . The water tanks used to " let the concrete cure for 7 and 28 days contains water which is suspect to be impure " that's it

RE: Quality of water curing concrete specimens in water tanks

use water that meets the requirements for mixing water, otherwise test it if you wish to let it sit for months without refilling

RE: Quality of water curing concrete specimens in water tanks

Water should be potable prior to introducing lime.

RE: Quality of water curing concrete specimens in water tanks

(OP)
Ok thanks for the responses all of you

RE: Quality of water curing concrete specimens in water tanks

From CSA A23.2, and is similar to ASTM C511:

5.8 Water storage tanks
5.8.1 General
Tanks shall be constructed of non-corroding materials. Automatic control of water temperature at 23 ± 2 °C shall be provided where the tank is located in a room not having the temperature controlled within this range and in any instance where difficulty in maintaining temperatures within the specified range is encountered. With the exception of water storage tanks located in a moist room or moist cabinet, all water storage tanks shall be equipped with a temperature recorder with its sensing element in the storage water.
Alternately, manual temperature readings shall be taken twice daily (e.g., early morning and late afternoon) at least 5 d per week with an accuracy of 0.5 °C. For the purpose of temperature recording, a group of water storage tanks may be considered one tank if the following three conditions are met:
(a) All tanks are interconnected with tubing that allows water to flow between the tanks;
(b) Some means of circulation is provided between the tanks; and
(c) Temperature variation between the tanks shall not exceed 1°C when checked and recorded weekly. The water in a storage tank shall be saturated with calcium hydroxide (high calcium hydrated lime) to prevent leaching of calcium hydroxide from the specimens (Note 2). Water not saturated with calcium hydroxide may affect test results due to leaching of lime from the test specimens and shall not be used in storage tanks. To maintain saturation with calcium hydroxide, excess calcium hydroxide shall be present.
For the purposes of lime saturation to prevent leaching, lime means high-calcium hydrated lime, not calcium carbonate (limestone). The water in the storage tank shall be thoroughly stirred at intervals not to exceed one month to help replace calcium ions that have depleted. Tanks shall be cleaned and refilled with water containing 3 g/L of calcium at intervals not to exceed 24 months (see Note 3).

Dik

RE: Quality of water curing concrete specimens in water tanks

KSE...the fact that you are growing stuff in the water indicates that you likely don't have enough lime in the water.

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