Building failures worldwide have been caused by improper design, inadequate supervision, and inferior materials. However, water quality is often overlooked in the concrete industry, which consumes a significant amount of freshwater. Mixing, found in freshly mixed concrete, plays a crucial role in forming hydration products, improving workability, and reserving space for accommodating hydration products Water supply varies significantly, with upland surface water having a low content of dissolved solids and softness, while underground water contains high hardness but low organic matter. Seasonal fluctuations in quality are observed in surface waters.
Too many impurities in mixing water can affect setting time and concrete strength, cause efflorescence, staining, reinforcement corrosion, volume instability, and decreased durability Impurities in mixing water can influence the resulting hydration reaction, leading to deterioration of (ICRETE) concrete. Regulations for the suitability of waters for mixing concrete are in place, but water not fit for drinking and also containing impurities like sea and waste are used for producing concrete. The assessment of water suitability for concrete is based on regulations prevailing in some parts of the world, which provide limitations on the number of impurities allowed for to be used in concrete.
Impurities in water should not be used if it contains huge amounts of suspended solids, dissolved solids, or organic materials. Suspended solids include silt, clay, pipework debris, organic matter, and colloids. Carbonates and bicarbonates influence the setting time of cement, and reliable sources of water are essential Sea water may sometimes be used for mixing concrete due to its higher early age strength but lower long-term strength. However, excessive chlorides can cause dampness, efflorescence, and increased risk of reinforcement corrosion, especially in tropical regions is a crucial component in concrete production, and its color or smell can indicate its potential harmful content.
Natural, slightly acidic, is harmless, but water with humic or organic acids may hinder concrete hardening. Sea, with a total salinity of about 3.5%, can sometimes be used for mixing concrete, but it can cause dampness and increase the risk of reinforcement corrosion. It is important to consider surface moisture of aggregates when using sea water Water for curing and washing concrete is less rigid due to its short contact time with the concrete. It may contain more inorganic and organic materials, sulfuric anhydride, acids, and chlorides than acceptable mixing Iron or organic matter may lead to staining, and water with free CO2 can attack concrete. It is recommended to send.
Water used for mixing and curing must be clean and free from harmful substances. Potable water is generally considered satisfactory for mixing concrete. The compressive strength and initial setting time tests should be conducted to determine the suitability of water for concrete production. Sea is not recommended due to its harmful salts, but it can be used for mixing or curing plain concrete with no embedded steel. The Indian Institute of Technology, Madras (IIT-M) has recommended the demolition and reconstruction of Chennai’s apartments due to poor water quality. The apartment complex in Choolaimedu area experienced severe structural damage in July 2023.
Endangering the lives of 500 families living in 17-storey buildings. The IIT-M has called for the immediate evacuation of residents and recommended that all three blocks of the apartment complex be demolished in a controlled manner. The report also recommends that Block A and Block B, which are in a more advanced stage of decay, be first demolished and reconstructed within a year. Blocks B and C after reconstruction can be used to house current residents, while Block C can be constructed as stage 2 of the repair work. New construction material should be tested to meet required standards The main cause for the deterioration in the apartment complex was chloride-induced corrosion.
Which was caused by the use of chlorine-contaminated water during the mixing and curing of concrete. The report confirms the CMDA’s suspicion that the deterioration had occurred primarily due to chlorine-contaminated The demand for concrete is expected to increase due to population to (BIS) growth, urbanization, and modern lifestyles, leading to an increased demand for mixing water. Contractors should select the best type of water while enhancing environmental sustainability and explore alternate sources of mixing water to overcome the current problems faced with existing water.
Q1. Why is water quality critical in RCC construction?
Water is a key ingredient in concrete; poor-quality water can reduce strength, cause corrosion, and create cracks in RCC structures.
Q2. Can tap water be used for concrete mixing and curing?
Not always. Tap may contain impurities or chemicals. Testing for hardness, pH, and contaminants is necessary before use.
Q3. Can untreated water still be used for curing?
Using untreated or unsafe water for curing can lead to weakened concrete and early deterioration.
Q4. How can we test water for RCC structures?
Standard tests include pH check, chloride content, sulphate content, and turbidity assessment.
Q5. What precautions should be taken to ensure water quality?
Always use potable water or treat local water sources, and avoid water with high mineral or chemical content.
