The sustainability of infrastructure projects is becoming increasingly important issue in engineering practice. This means that in the future the construction materials will be selected on the basis of the contribution they can make to reach sustainability requirements. Geopolymers are materials based on by-products from industries. By using geopolymer concrete technology it is possible to reduce our waste and to produce concrete in the environmental-friendly way. An 80% or greater reduction of greenhouse gases compared with Ordinary Portland Cement (OPC) can be achieved through geopolymer technology. However, there are limited practical applications and experience. For a broad and large scale industrial application of geopolymer concrete, challenges still exist in the technological and engineering aspects. The main goal of GeoCon Bridge project was to develop a geopolymer concrete mixture and to upscale it to structural application. The outputs of projects provide input for development of recommendations for structural design of geopolymer based reinforced concrete elements. Through a combination of laboratory experiments on material and structural elements, structural design and finite element simulations, and based on previous experience with OPC concrete, knowledge generated in this project provides an important step towards a “cement free” construction. The project was performed jointly by three team members: Microlab and Group of Concrete Structures from Technical University of Delft and Technical University of Eindhoven.@en

It has been shown in the literature that a secondary low salinity waterflood can improve the oil recovery by 5-20%. A possible mechanism is that the low salinity causes desorption of organic material, which may increase water-wetness and lead to more favorable relative permeability behavior. A less well-known mechanism is enhanced solvent (e.g., carbonated water) recovery as low salinity enhances the aqueous solubility of neutral components, which after injection will be transferred from the aqueous phase to oleic phase thus decreasing the oil concentration in the oleic phase and diluting the residual oil. By way of example we consider a low salinity carbonated waterflood into a reservoir containing oil equilibrated with high salinity carbonated water. For a given pH, the CO2 equilibrium concentration in low salinity injection water is higher than in the high salinity initial water. PHREEQC, a geochemical aqueous equilibrium programme, can be extended to obtain the accurate partition coefficient of neutral species that are soluble both in the oleic and the aqueous phase. For this we use the Krichevsky-Ilinskaya extension of Henry’s law for solubility of gases in liquids. Gibbs phase rule shows that the phase behavior only depends on the pH and the chloride concentration. In PHREEQC, we use Pitzer’s activity coefficients to extend the validity up to 6M. The output of PHREEQC can only be successfully incorporated in multiphase flow simulation programmes, e.g. COMSOL(TM), after applying a smoothing procedure for which we choose symbolic regression (EUREQA(TM)). An optimal formulation avoids spurious broadening of the concentration profiles in contact “discontinuities”. We obtain the saturation, composition and the total Darcy velocity profiles. The significant new insight is that by changing the salinity at constant pH the oil recovery by carbonated water flooding can be enhanced. This insight can be applied to optimize enhanced oil recovery with a low salinity waterflood. @en