In construction, three-dimensional concrete printing technology is an innovative method that opens new design possibilities, reducing the construction time process. The incremental material deposition allows organic shapes without formwork, a mandatory constraint in preparatory phases of conventional complex concrete structures. Nowadays, in three-dimensional printing for construction industry, concrete is the most used material due to its workability, extrudability, and pumpability properties favorable for the printing conditions. Hence, this composition still has a poor sustainable efficiency due to the high levels of Portland Cement. In this research, a reduction of this material was studied and experimented searching for a mortar composition with better ecological footprint, with the objective of decreasing the CO₂ emissions. A bibliometric analysis was made to study the constituents of a mortar for three-dimensional printing and respective dosage. The knowledge acquired in the analysis of the compositions contributed to the development of mortars with lower Portland Cement content. A mechanical extruder was used to check the extrusion capacity of the developed mortars, and the best compositions are presented.

This paper deals with integration of energy storage systems into electricity markets. We explain why the energy storage systems increase flexibility of both power systems and energy markets and why such flexibility is desirable, particularly when variable renewable energy sources are being used in existing power systems. As opposed to the existing literature, our model includes a dual technology energy storage system, acting in two different markets. We introduce a mathematical formulation for this model applied to two Dutch electricity markets. Adopting optimal control approach with the goal to maximize the yearly benefit, we show that the dual energy storage system can be profitable already when the same buying/selling strategies are adopted for the working days and weekends. We show that the profitability (slightly) increases with different buying/selling strategies for the weekdays and weekends. Finally, we demonstrate how the yearly benefit varies with size and efficiency of the devices chosen and market prices.