- Home
-
Products & Solutions
-
Industries & Workplaces
- Find Products by Industries
- Chemical
- Pharma & Biotechnology
- Food & Beverage
- Academia and Education
- Testing Labs and Health Institutes
- Metal, Plastic and Electronics Components
- Raw Materials & Jewelry
- Pulp, Paper & Textile
- Engineering, Machinery & Equipment Manufacturing
- Transport and Logistics
- Utilities and Municipalities
- Retail
- Find Products by Workplaces
- Research & Development
- Engineering, Process Development and Scale-Up
- General Laboratory, Inspection and Quality Control
- Receiving and Warehousing
- Production and Processing
- Packaging and Filling
- Logistics, Shipping and Mail
- Maintenance & Service
- IT / Information Technology
- Retail
- Water, Power & Facility Utilities
- Services & Support
- About Us
- Contact Us
|
|
Cement Determination to BS EN 196-2:2005
Jan 22, 2008
In the ever changing environment of the 21st century, the construction of new buildings and infrastructure seems to be a non-stop process.
In order to ensure the longevity and durability of these buildings, stringent quality standards are applied to all stages of the construction process. However, the key prerequisite for high quality construction work is high quality raw materials. The testing of concrete and the cement that constitutes it is therefore of vital importance.
The chemical make-up of the cement and any impurities present can adversely affect the performance of the finished product. For instance, too high a chloride content can lead to corrosion of reinforcement steelwork in concrete, Too high an alumina content can cause a reduced strength and a lack of resistance to chemical attack. The methods for determining these characteristics are detailed in
BS EN 196-2 : 2005.
In order to ensure the longevity and durability of these buildings, stringent quality standards are applied to all stages of the construction process. However, the key prerequisite for high quality construction work is high quality raw materials. The testing of concrete and the cement that constitutes it is therefore of vital importance.
The chemical make-up of the cement and any impurities present can adversely affect the performance of the finished product. For instance, too high a chloride content can lead to corrosion of reinforcement steelwork in concrete, Too high an alumina content can cause a reduced strength and a lack of resistance to chemical attack. The methods for determining these characteristics are detailed in
BS EN 196-2 : 2005.
The methods described in this standard use a variety of analytical techniques, including:
• Gravimetric analysis – determination of silica by precipitation and weighing. For more information click here
• Complexometric titration – determination of Calcium, Magnesium, Iron and Aluminium
• Precipitation titration – determination of Chloride and Sulphate
In all of these cases, METTLER TOLEDO has an equipment solution to help. This page also contains links to a wealth of customer testimonials, application notes and other useful information. If you need more specific advice or assistance please call our team of specialists on 0116 235 7070.
To obtain a full copy of the BS EN 196-2 standard click here
To see how METTLER TOLEDO has helped customers in this industry segment, see the article in our user magazine UserCom 11
Our Thermogravimetric Analyzer TGA/DSC1 is also ideally suited for cement determination - for more information about this instrument click here
• Gravimetric analysis – determination of silica by precipitation and weighing. For more information click here
• Complexometric titration – determination of Calcium, Magnesium, Iron and Aluminium
• Precipitation titration – determination of Chloride and Sulphate
In all of these cases, METTLER TOLEDO has an equipment solution to help. This page also contains links to a wealth of customer testimonials, application notes and other useful information. If you need more specific advice or assistance please call our team of specialists on 0116 235 7070.
To obtain a full copy of the BS EN 196-2 standard click here
To see how METTLER TOLEDO has helped customers in this industry segment, see the article in our user magazine UserCom 11
Our Thermogravimetric Analyzer TGA/DSC1 is also ideally suited for cement determination - for more information about this instrument click here
Complexometric Titrations
This technique involves the use of complexing agents such as EDTA or DCTA, as titrating agents, to form complexes with the metal ions present in cement. The end point of the titrations is monitored by colour changes indicated by a variable wavelength photometric probe. Curves and data are evaluated by the Excellence titrator. By varying the chosen indicator, conditions of pH and by using masking agents, selective determinations of a variety of metals can be made.
All of the methods listed below make use of a sample stock solution that is prepared by high temperature acid digestion of a cement sample. The full text of the BS EN 196-2 standard describes methods for sampling and digestion of cement samples.
Once the sample solution is prepared, the following test methods can be used. The links will take you to a fuller description of the methods and method parameters:
(you will need to register to access them)
1. Calcium oxide (CaO)
20mL of sampole are diluted with 25ml deionised water
10mL of triethanolamine solution (20%) are added to mask (Al and Fe)
The pH is adjusted to 12.5 by addition of NaOH solution 4mol/L
Titration is performed with EDTA 0.03mol/L with Murexide 0.1% indicator
Phototrode set to measure at 620nm
This technique involves the use of complexing agents such as EDTA or DCTA, as titrating agents, to form complexes with the metal ions present in cement. The end point of the titrations is monitored by colour changes indicated by a variable wavelength photometric probe. Curves and data are evaluated by the Excellence titrator. By varying the chosen indicator, conditions of pH and by using masking agents, selective determinations of a variety of metals can be made.
All of the methods listed below make use of a sample stock solution that is prepared by high temperature acid digestion of a cement sample. The full text of the BS EN 196-2 standard describes methods for sampling and digestion of cement samples.
Once the sample solution is prepared, the following test methods can be used. The links will take you to a fuller description of the methods and method parameters:
(you will need to register to access them)
1. Calcium oxide (CaO)
20mL of sampole are diluted with 25ml deionised water
10mL of triethanolamine solution (20%) are added to mask (Al and Fe)
The pH is adjusted to 12.5 by addition of NaOH solution 4mol/L
Titration is performed with EDTA 0.03mol/L with Murexide 0.1% indicator
Phototrode set to measure at 620nm
2. Magnesium oxide (MgO)
10mL of sample solution is diluted with 25ml deionised water.
10mL of triethanolamine solution (20%) are added to mask (Al and Fe)
The pH is adjusted to 10.5 with concentrated Ammonia.
Titration is performed with DCTA 0.01mol/L with Methylthymol blue 1% indicator
Phototrode set to measure at 620nm
3. Iron (III) oxide (Fe2O3)
20ml of sample are diluted with 30ml deionised water.
A few drops of sulphosalycilic acid indicator 1% are added
The pH is adjusted to 1.5 with 10% Ammonia solution
The sample is heated to 47+/-3°C.
Titration is performed with EDTA 0.02mol/L
Phototrode set to measure at 520nm
4. Aluminium oxide (Al2O3)
20mL sample are diluted with 25ml deionised water.
The pH is adjusted to 2.0 with Ammonia solution and then to pH 3.0 by addition of ammonium/acetate buffer.
4mL of EDTA 0.02mol/L is added and the solution is boiled for 3 minutes.
After cooling, 10 drops of PAN and 4 drops of Cu-EDTA are added.
Titration is performed with CuSO4 0.02mol/L.
Phototrode set to measure at 555nm
PAN = 1-Pyridine(2)azo-naphtol-2 in ethanol
Cu-EDTA is a 1:1 mixture of CuSO4 0.05mol/L and EDTA 0.05mol/L
Precipitation Titrations
These tests involve the addition of titrating agents that form insoluble salts with components in the cement sample. The end point of these reactions is generally measured potentiometrically with either a silver electrode, or another ion selective electrode.
Chloride determination
This method is relevant to both cement testing, as well as for those companies testing concrete drilling samples. Too much chloride in cement can adversely affect the strength and durability of the finished concrete product, and monitoring the chloride content in situ can help determine the safety status of existing structures.
After digestion in hot, concentrated nitric acid, the cement samples can be diluted and titrated directly with Silver Nitrate solution. The end point is indicated using a silver rod electrode and a separate Ag/AgCl reference electrode. The method given is a generic chloride determination method that will cope adequately with the cement samples.
These tests involve the addition of titrating agents that form insoluble salts with components in the cement sample. The end point of these reactions is generally measured potentiometrically with either a silver electrode, or another ion selective electrode.
Chloride determination
This method is relevant to both cement testing, as well as for those companies testing concrete drilling samples. Too much chloride in cement can adversely affect the strength and durability of the finished concrete product, and monitoring the chloride content in situ can help determine the safety status of existing structures.
After digestion in hot, concentrated nitric acid, the cement samples can be diluted and titrated directly with Silver Nitrate solution. The end point is indicated using a silver rod electrode and a separate Ag/AgCl reference electrode. The method given is a generic chloride determination method that will cope adequately with the cement samples.
Sulphate determination
The digested sample solution can also be tested for Sulphate content. Several methods are available, but in general they all rely on addition of Barium Chloride solution with precipitation of the Sulphate present in solution as the insoluble barium Sulphate. The excess of barium present is then detected by means of:
• Titration with EDTA monitored by a barium ion selective electrode
• Titration with sulphuric acid monitoring the conductivity of the solution
A summary of the various methods available for the determination of sulphate in solutions is given in our user magazine UserCom 10
For both tests the titration excellence units are again ideal for control of the titrant addition and data acquisition. To see an on-line demonstration of these instruments click here
These titration tests are very easy to automate using sample changer technology, which can provide benefits in terms of:
• Unattended operation
• Overnight analysis
• Productivity gains
• Cost savings and high return on investment
A wide variety of automation solutions are available. For an example click here