Research

Activities  

The research projects can be classified by themes, the principal are:

1. Development of testing methods  

The laboratory of CRIC-OCCN is accredited by Belac for many tests on cement, mortars and concretes. The Research Department of CRIC-OCCN develops new testing methods which are then the object of an accreditation and be applied in routine by the laboratory after training of its technical staff. As example, alternative methods for the determination of the Hexavalent Chromium content of cements (easier and less expensive than the method described in the EN 196-10) are under development in collaboration with French organizations. Another example is the development of methods for the determination of the soluble P2O5 and reactive silica in fly-ashes.

A recent project in this field is the research called “NBN B 15-250”. It currently does not exist well defined and sufficiently precise methods of investigation making it possible to determine a posteriori the content of cement of a hardened concrete. In the absence of a European standard, the Belgian laboratories refer today to the NBN B 15-250 standard: 1991 proposing a calculation method of the content of cement being based on the chemical analysis of the concrete. However, this standard presents, in its current version, many limits and is of interest only if the cement and the other components of the concrete are available or known.

2. Durability of concrete  

Several research projects are in relation to durability.

The first project called “Freeze-thaw” relates to the resistance of the concretes to the freeze-thaw cycles. In this study, the freeze-thaw testing methods of the European Technical Specification CEN/TS 12390-9 are compared with those used usually in Belgium. The goal of this project is to establish correlations between the various methods and establish criteria of performance for the Belgian concretes with respect to the freeze-thaw resistance cycles.

Another project, in progress with BBRI, is concentrated on corrosion problems of reinforced concrete caused by the chlorides ions or the carbonation. This research reached its last part “Durability - part Sulphates” that concerns the study of the resistance against sulphates of mortars and concretes.

Other studies of durability relate to the Alkali-Silica Reaction (ASR), the means of measuring and quantifying it. In a first alternative, the reactivity of European aggregates with a cement chosen for its high and constant quantity of alkali is examined. In the second alternative, the maximum alkali content which can be allowed in a cement in contact with a sensitive aggregate is evaluated.

A new international study group (Rilem TC ACS), for which the participation of the Research Department has been requested, has been just formed to study more in-depth the accelerated testing methods of RAS on formulations of concrete.

A last project is called “Beslag” the goal of this study is the integration of high quantities of certain industrial by-products in the concretes to reduce their environmental impact while ensuring a long lifetime to the concrete structures.

3. Environment / Health  

Examples of this type of researches are linked to “leaching” (the extraction of soluble components out of the concrete) and the determination of “alveolar crystalline silica” in air.

Two leaching projects are actually ongoing.

The first one concerns the potential release of heavy metals present in the concrete in contact with potable water, according to "EAS" (European Acceptance Scheme).

The second project concerns the extraction of organic products (admixtures) towards the water in contact with the concrete. This is the subject of a PhD-study managed by the Research Department at the request of the French cement and admixture industries. The tuning of the measurement method to determine the extracted heavy metals has required a complex research: indeed, we had to detect traces of metallic elements in the order of ppb (µg/kg) with a resolution of the ppt (ng/kg). The second project is at least as difficult, knowing that at the moment no direct applicable method exists to measure such a low quantities of such long organic molecules.

The project « Crystalline Alveolar Silica » is created in order to help essentially the cement and the quarry industries in order to be conform with the recently signed European intersectorial agreement of the protection of employees. This implicates that the total alveolar dust sampled by the CTP (Centre Terre et Pierre) on sensitive working places in the concerning industry is measured by the CRIC-OCCN. The development of such a technique is also of great complexity given the very low quantities of dust sampled. The order of magnitude of dust weight is the milligram and must be measured with a precision of micrograms. The accent of this guideline is set on prevention and therefore on the ways to decrease the amount of detrimental dust.

A last project in this category is « Tefracem » (Tefra means ash in old Greek) which will start in 2009. This project aims to valorise the residues of thermal processes in construction materials ; more specific, the project foresees to treat the fly ashes and the residues of the purification of cremation dusts in order to add these materials to the cement as a hydraulic binder (mineral addition type II) or as an inert filler as sand or fine aggregates.

4. Instrumentation  

Projects, linked to instrumentation are natural in a research laboratory. They may consider the construction of an instrument, as the development of an original minipenetrometer that destinated to evaluate the setting of the cement or the development of a conduction calorimeter. Another type of projects considers the extension of competences in certain measurement domains or instrumentations as this of the electronic and optic microscopy or the quantitative determination of constituents using X-Ray Diffraction techniques.

5. Materials  

This type of projects is the most frequent at the Research Department. Here, we can mention, as an example the project that deals with, the identification and quantification of admixtures in the hardened concrete matrix, can be mentioned. This very long research is at the time being subject of a feasibility study.

Another project concerns the resistance to the punching by columns of large tiles reinforced with metallic fibres. The large sizes of the tested tiles constitute an unusual parameter that requires particular installations.

A third project is related to the applications development of fiber reinforced concrete for the precast and in-situ casting industries (Project BEFIME).

A PhD-study performed by one of our researchers concerns the “Comparative study of cements on the basis of blast furnace slag”. It involves the evaluation of the ageing effect of blast furnace slags used as type II addition on the reactivity of the hydraulic binder.

The European working group « Ad Hoc group » of the CEN TC 51 WG 6 has mandated the CRIC-OCCN to characterize a new ternary cement “CEM X” with high limestone filler contents.

6. Workability of concrete  

The potential effect of certain admixtures on the workability of concrete has been studied. Another projects are the development of a method that enables to correlate the rheological properties of a mortar (Mortar-Concrete Equivalent) with this of concrete or furthermore the development an electrical resistivity technique to measure the setting time of concretes in the field.