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The EN206 Concrete Conformity database has been completely reviewed and re-written to increase capacity and some major design changes have occurred. The EN206 conformity reporting functions have also been completely reviewed and enhanced where possible.
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Previous EN206 Concrete Conformity Database
Version 1.1 of the EN206 database operates with a limited number of mix designs and was seen to be restrictive. This remains the case as the physical size of the database becomes an issue with lower capacity computers. Version 1.1 of the EN206 Concrete Conformity database is now archived.
Development Version v2.0
Version 2.0 has seen a complete re-write from the ground up. The only thing that really remains from version 1.1 are the formula and math used in the calculations of the EN206 conformity reporting figures. It was important to keep these the same as version 1.1. The original version has seen several audits by QSRMC and BSI and to change these may damage any audit confidence in the system core functionality.
These EN206 Conformity system enhancements have increased the core functionality and with this the complexity has also increased. Whilst an experienced concrete technologist may understand the principles used in its construction a person unfamiliar with concrete technology may not.
A detailed user manual is supplied to customers who purchase this conformity system. This manual will not be available otherwise. It should be noted that the coding has been more streamlined and the amount of embedded objects have been considerably reduced. There are also fewer screens to manage.
Listed below are the main Conformity Database changes:-
Startup
The main startup screen has changed. The old menu for editing has been removed as this has become a comprehensive master system analysis tool. Editing now occurs from the cube datasheet in the control screen.
Main Relationship Analysis
The Conformity Database can now deal with an unlimited amount of mix designs. The system now uses batchbook references.
Mix Design
Mix Design can be of any concrete mix design imaginable. The only stipulation is that all mix designs must have an established relationship with the main concrete mix design and be of the same family of concrete mixes. An EN206 mix family is determined by the concrete mix constituents being of the same type and physical properties, including the cement type.
EN206 Database Master Analysis Tool
The development tool used to re-write the system has been left in place as I think this offers some advanced features for the user.
EN206 Database Strength Lists
The system will run without any strength lists being used. The system runs entirely from the input MRA, density and slump adjustment data. This is because users may run their own strength lists generation tool.
EN206 Consistency Conformity
EN206 Consistency conformity analysis has now been enhanced to include both spot and composite sampling. The previous system used the most onerous conformity requirements.
Density Conformity to EN206?
This database uses more stringent control parameters than are required by EN206. This has been brought into line with the QPA recommendations including reference to BS EN 12390-7 :Testing Hardened Concrete Part 7 - Density of hardened concrete shall be to "Water Saturated" condition. It should be noted that Dataseen does not consider current density analysis requirements will be accurate enough to gain any valuable information from. The overall report average density has been tailored to suit a more meaningful range of +/- 40 kg. This does not constitute EN206 density compliance rather a parameter that would warrant further investigation into the overall concrete mix design for yield maybe?
In my opinion and experience concrete producers need to monitor density more closely than recommended. Concrete density trends may indicate problems with constituent material property changes or problems with concrete plant weigh gear, which may in turn affect the delivered volume to Customers, albeit minor. If the volumetric properties of the concretes change it will have a small effect on designed cement content per volumetric cubic metre, which in turn may affect the strength control system, this may only represent 0.5 to 1.0 MPa but when related to between 5 to 7 kg of cement per 1MPa a quick cost analysis can be derived. A concrete producer also keeps regular checks on bulk density of aggregates which also can be used to monitor any volumetric property deviation.
EN206 seems to be aimed at individual density variation with no provision for trend conformity. In my opinion the Dataseen EN206 Concrete Conformity database adds value to concrete density analysis both for the producer and the end user.
Concrete Fresh Density
Concrete fresh density should not be confused with hardened cube density, they are not the same. However, a relationship can be established between concrete fresh density and the associated 28 days saturated hardened cube density. As cement hydration takes place it will continue rapidly up to approx 28 days for PC cements and up to approx 56 days for cement replacement concrete mixes (GGBS or PFA). As the concrete gets stronger it also increases in physical density (look up, ' the effects of concrete hydration' on the internet for a more detailed discussion about hydration).
A typical relationship is, for example, a quartzitic naturally rounded gravel aggregate combined with a ordinary portland cement may increase in weight by approx 40 kg per cubic metre or 1.6% after 28 days curing time. However, this may differ slightly throughout the cement content range for the same mix design and therefore becomes a variable. Relationship analysis finds it difficult to deal with variables be they known or unknown. Why go to all the trouble trying to find out the relationship between fresh wet density and hardened cube density when the comparative analysis is already available with non-variable data, ie the hardened cube density of the original trial mixes and production concretes.
The whole idea about concrete family relationships is that we have a benchmark established against which we analyse current product performance. Concrete density is no different, why not simply compare hardened cube density to the original trial data cube density. The variations measured will be confident as the benchmark is a known constant which is the original raw data of the hardened cube density!
All things being equal, by using hardened cube density we can accurately and more importantly, confidently, detect abnormal trends and deviation from the intended design.
The one thing that would reduce confidence in any density retro-analysis is the cube storage conditions. The curing conditions are critical for consistency of any analysis. Confident consistency can only be achieved in a controlled laboratory environment where daily records are kept on curing conditions both ambient and curing tank water temperature. If things go wrong with the concrete density analysis the lab records will be first place to check.
Quick View Screen
7 to 28 Day Strength relationship, hereafter known as correlation. This is now totally automated and the user inputs both the 7 days and the 28 days MRA strength data. The system will calculate any correlation deviation. There is now a detailed correlation history chart available. This may show correlation trend changes during the course of the annual seasonal climate changes! It may also indicate problems with cement quality. It should noted that at least three 7 and associated 28 days results should be input to activate the correlation automation formula.
EN206 database System provides all the appropriate Conformity Reports and Chart Prints:
Minimum System Requirements
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Windows 98/ME/2000/Xp
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Processor speed > 233Mhz
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Microsoft Access 2000
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Minimum 32Mb memory
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10Mb of disk space
More EN206 Concrete Conformity system Development
I guess the next natural step in development would a complete database to cater for multiple concrete plants using multiple mix design packages, now that would be useful tool.
Join our forum to discuss further....
Concrete Strength Control System
We have discussed the requirements of EN206 here at Dataseen, but what we haven't discussed is the general control of concrete strength.
You do not have to use this system just for EN206 conformity. It will work as a general concrete strength control system. This is because is has a simple forecasting system built into it. It can generate strength lists for your concrete batching plants as well.
If you do not need to comply with EN206 then consider using this system as a general quality control tool for your ready mixed concrete production operation. If you use it like this the only strength analysis report you will need is the Mean Strength and Standard Deviation analysis. All the other reports will be analytically useful as well providing some commercial decision making analysis.
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