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influence of water hardness on concrete surface

influence of water hardness on concrete surface

Influence of water hardness on concrete surface ...

01/09/2010  A number of different factors have been found to affect the surface erosion rate, including the type of cement, w/c, curing, and the water hardness of the WWTP. The surface erosion of the concrete with a w/c of 0.50 has been observed to depend on the CaO contents of the cements used (Leemann et al., 2009, Leemann et al., 2010).

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Influence of water hardness on concrete surface ...

The CaO content of the cement used, the water-to-cement ratio, and curing affect the resistance of the concrete to acid attack. However, both experimental data and thermodynamic modeling show that water hardness is the dominating parameter for surface erosion. In the presence of high water hardness, the protons produced by the nitrifiers are buffered and the calcite precipitation occurring in ...

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Influence of water hardness on concrete surface ...

In aeration tanks of wastewater treatment plants (WWTP), biodeterioration can lead to a partial dissolution and ensuing erosion of the concrete due to an acid attack caused by the nitrifying biofilm covering the tank surface. In this study, concrete samples were exposed in four different WWTP. The CaO content of the cement used, the water-to-cement ratio, and curing affect the resistance of the...

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(PDF) Influence of water hardness on concrete surface ...

Influence of water hardness on concrete surface deterioration caused by nitrifying biofilms in wastewater treatment plants September 2010 International Biodeterioration Biodegradation 64(6):489-498

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(PDF) Influence of water hardness on concrete surface ...

Influence of water hardness on concrete surface deterioration caused by nitrifying biofilms in wastewater treatment plants International Biodeterioration Biodegradation, 2010 Andreas Leemann

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(PDF) Influence of water hardness on concrete surface ...

Influence of water hardness on concrete surface deterioration caused by nitrifying biofilms in wastewater treatment plants International Biodeterioration Biodegradation, 2010 Andreas Leemann

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Influence of water hardness on concrete surface ...

The CaO content of the cement used, the water-to-cement ratio, and curing affect the resistance of the concrete to acid attack. However, both experimental data and thermodynamic modeling show that water hardness is the dominating parameter for surface erosion. In the presence of high water hardness, the protons produced by the nitrifiers are buffered and the calcite precipitation occurring in ...

get price

Water in Concrete For Construction Pros

23/04/2014  The amount of water in concrete controls many fresh and hardened properties in concrete including workability, compressive strengths, permeability and watertightness, durability and weathering ...

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Factors Affecting Strength of Concrete - The Constructor

The relation between water cement ratio and strength of concrete is shown in the plot as shown below: The higher the water/cement ratio, the greater the initial spacing between the cement grains and the greater the volume of residual voids not filled by hydration products. There is one thing missing on the graph. For a given cement content, the workability of the concrete is reduced if the ...

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What is the relationship between hardness and the concrete ...

Hardness is a property to do with the surface of an object. Surface harness of concrete can be measured using different devices, such as hammer, electronic transducer, etc. Whereas strength is measured by testing cubes for compressive strength, or beams for flexural strength, or cylinder for tensile strength (slit test). Best wishes

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Myths and misconceptions about concrete and water

26/07/2010  Concrete needs a very specific water content for a few hours until it "sets" -- which means that it gets hard enough that more water or rain will not wash it away. Then it needs to stay moist for a minimum of 3 days to obtain its minimum acceptable strength. When the atmosphere is hot and dry we often cover the concrete to reduce evaporation, or put a sprinkler on it to keep it wet. So that ...

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Environmental impact of concrete - Wikipedia

Concrete is used to create hard surfaces which contribute to surface runoff that may cause soil erosion, water pollution and flooding. Conversely, concrete is one of the most powerful tools for proper flood control, by means of damming, diversion, and deflection of flood waters, mud flows, and the like. Light-colored concrete can reduce the urban heat island effect, due to its higher albedo ...

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Q: Why is hitting water from a great height like hitting ...

25/07/2012  Surface tension of water gives much easier than the surface tension of concrete. The initial impact does the damage with the water, once that surface tension is broken that impact pressure reduces greatly. With concrete that impact pressure does not reduce at all. It is a dead stop, water gives and its a slower stop. Will still kill you, but the idea that water is ‘like concrete’ isn’t ...

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Effects of Rain on Concrete and How to Prevent It?

15/10/2020  A damaged concrete surface will obviously also invite more water in and then comes the freeze-thaw cycles. In fact, freeze and thaw cycles aggravate the damage and lead to cracking. Thus, the Effect of Rain on Concrete will cause it to lose surface strength, giving rise to more issues in the future. #3. Concrete Scaling.

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Why concrete + rain = flash floods Flooding The Guardian

25/07/2016  Why concrete + rain = flash floods Britain’s front gardens are being paved for parking while back gardens become patios. But in Canada and the US, the Depave movement is tearing up hard

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Factors Affecting Strength of Concrete - The Constructor

The relation between water cement ratio and strength of concrete is shown in the plot as shown below: The higher the water/cement ratio, the greater the initial spacing between the cement grains and the greater the volume of residual voids not filled by hydration products. There is one thing missing on the graph. For a given cement content, the workability of the concrete is reduced if the ...

get price

What is the relationship between hardness and the concrete ...

Hardness is a property to do with the surface of an object. Surface harness of concrete can be measured using different devices, such as hammer, electronic transducer, etc. Whereas strength is measured by testing cubes for compressive strength, or beams for flexural strength, or cylinder for tensile strength (slit test). Best wishes

get price

Myths and misconceptions about concrete and water

26/07/2010  Concrete needs a very specific water content for a few hours until it "sets" -- which means that it gets hard enough that more water or rain will not wash it away. Then it needs to stay moist for a minimum of 3 days to obtain its minimum acceptable strength. When the atmosphere is hot and dry we often cover the concrete to reduce evaporation, or put a sprinkler on it to keep it wet. So that ...

get price

Strength development in concrete - Understanding Cement

For example, a concrete mix containing 400 kg cement and 240 litres (=240 kg) of water will have a water/cement ratio of 240/400=0.6. The water/cement ratio may be abbreviated to 'w/c ratio' or just 'w/c'. In mixes where the w/c is greater than approximately 0.4, all the cement can, in theory, react with water to form cement hydration products. At higher w/c ratios it follows that the space ...

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7 FACTORS INFLUENCING REBOUND HAMMER TEST OF CONCRETE

22/11/2019  A wet surface will give rise to underestimation of the strength of concrete calibrated under dry conditions. In structural concrete, this can be about 20 percent lower than in an equivalent dry concrete. 4. Curing and Age of Concrete. Influence of Curing and Age of Concrete The relationship between hardness and strength varies as a function of ...

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Q: Why is hitting water from a great height like hitting ...

25/07/2012  Surface tension of water gives much easier than the surface tension of concrete. The initial impact does the damage with the water, once that surface tension is broken that impact pressure reduces greatly. With concrete that impact pressure does not reduce at all. It is a dead stop, water gives and its a slower stop. Will still kill you, but the idea that water is ‘like concrete’ isn’t ...

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Concrete Slab Surface Defects: Causes, Prevention, Repair

shrinkage of the surface concrete, stresses develop that exceed the concrete’s tensile strength, resulting in surface cracks. (Under certain combinations of conditions, warping or curling can result from these stresses, too. See Curling.) Plastic-shrinkage cracks are of varying lengths, spaced from a few centimeters (inches) up to 3 m (10 ft) apart, and often penetrate to middepth of a slab ...

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Why concrete + rain = flash floods Flooding The Guardian

25/07/2016  Why concrete + rain = flash floods Britain’s front gardens are being paved for parking while back gardens become patios. But in Canada and the US, the Depave movement is tearing up hard

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Concrete Delamination - Causes and How To Avoid ...

This natural settlement causes excess mix water and entrapped air to be displaced (called bleeding), and the lighter materials migrate toward the surface. If finishing operations start prematurely and close or seal the surface before bleeding is completed, air and/or water are trapped under the densified surface mortar. As concrete hardens, subsurface voids develop where the water or air is ...

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Properties of Concrete - Workability, Setting, Bleeding ...

19/03/2017  Following are the factors that affect the setting of concrete. 1. Water Cement ratio 2. Suitable Temperature 3. Cement content 4. Type of Cement 5. Fineness of Cement 6. Relative Humidity 7. Admixtures 8. Type and amount of Aggregate. 2. Workability of Concrete. Workability is often referred to as the ease with which a concrete can be transported, placed and consolidated without excessive ...

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