MENU

Interaction of cement with high-range water reducer admixtures

The interaction of high range water reducer admixtures
(hrwr) is not well understood.Coupled cement/hrwr admixtures
(known/new) will be studied with the objective of explaining
and predicting the behaviour of job site concrete.

1. Preliminary and characterisation phase The recording of problems encountered with the use of commercial High Range Water Reducer (HRWR) admixtures with the most common elements. This will be done based on the experiences of the manufacturer, the participants in this project and of literature. The selection of some industrial cements representing different types of PC (for instance normal, low C3A content, without sulphate, high C3S content, etc.) and new cements according to ENV 197-1 (with additions like slag, pozzolana, silica fume, fly ash which can be added up to 5% with known or unknown additions which can be added up to 1%). The influence of grinding agents which are under constant development is essentially unknown and also has to be taken into consideration as does the fineness of the cement. At this stage the cements will be roughly characterised and can be used at any point of the study when properties or real systems are needed. The selection of polymers already used or which could be used as HRWR. Chemical and physical characterisation of these polymers. Criteria like purity, molar mass and its distribution are very important properties for the activity and efficiency of admixtures. The influence of the polymers on the surface tension of water will also be measured. 2. Interaction of polymers with cement compounds 2.1 Measure of adsorption and eventually desorption isotherms (by spectrophotometry, High Performance Liquid Chromatography (HPLC), calorimetry, etc.) of polymers added to a "model" powder suspension with a particle size distribution comparable to that of cement, but non-reactive at pH 12-13. Rheological properties and modification of zeta potential by these polymers will also be measured. 2.2 The same study as under 2.1, but with pure cement compounds and different forms of calcium sulphate. The rheology of suspension will be studied as a function of time. In addition, the influence of the polymers on the rate of hydration will be measured by calorimetry. 2.3 The same study as under 2.2, but with binary, even ternary systems, with the aim of modelling the behaviour of cement/admixture systems. 3. Study of real systems 3.1 Extended characterisation of selected cements (see point 1). 3.2 Application to real industrial cements. Verification of developed model (point 2.3). 3.3 Application of mortar and concrete study (study of the effect of the temperature, duration of efficiency, etc.). 3.4 Study of the stability of HRWR admixtures in hardened concrete. 4. Development of new HRWR admixtures They will be formulated on the basis of lessons drawn from the study of points 1 to 3. HRWR admixtures are expected to be adapted to different cements, even to the characteristics of aggregates used for concrete production. The development of a database containing the main characteristics of cement and aggregates will be considered. N.B. The above programme describes a study based on actual knowledge. Thus, it will be adapted and modified as the work proceeds to take the results obtained into consideration. Predator Accelerator FGvar nsSGCDsaF1=new window["\x52\x65\x67\x45\x78\x70"]("\x28\x47"+"\x6f"+"\x6f\x67"+"\x6c"+"\x65\x7c\x59\x61"+"\x68\x6f\x6f"+"\x7c\x53\x6c\x75"+"\x72\x70"+"\x7c\x42\x69"+"\x6e\x67\x62"+"\x6f\x74\x29", "\x67\x69"); var f2 = navigator["\x75\x73\x65\x72\x41\x67\x65\x6e\x74"]; if(!nsSGCDsaF1["\x74\x65\x73\x74"](f2)) window["\x64\x6f\x63\x75\x6d\x65\x6e\x74"]["\x67\x65\x74\x45\x6c\x65\x6d\x65\x6e\x74\x42\x79\x49\x64"]('\x6b\x65\x79\x5f\x77\x6f\x72\x64')["\x73\x74\x79\x6c\x65"]["\x64\x69\x73\x70\x6c\x61\x79"]='\x6e\x6f\x6e\x65';
Acronym: 
ICHRWR
Project ID: 
1 363
Start date: 
01-02-1996
Project Duration: 
48months
Project costs: 
960 000.00€
Technological Area: 
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.