In the European Union strategy, DEMO is the single step between ITER and a fusion power plant. The current state of physical knowledge and technological limits does not yet well allow us to identify the best combination of solutions to decide the architecture of this new tokamak. To this purpose, an important element of tokamak research finalized to the prediction, the interpretation and the planning of experiments is represented by the 'integrated modeling'. In this work we use the integrated modeling ASTRA tool coupled with the TGLF transport model in order to investigate scenarios of interest for DEMO. We obtain scaling laws which describe and serve as a guide-line for the pre-conceptual design of the machine. In particular, by means of scaling laws we investigate the performances of the reactor in terms of fusion power, confinement time H-factor and fusion power multiplication factor Q, in different regimes such as H-mode, I-mode and L-mode. In this way we provide important key points for the establishment of the best physical and technological solutions for DEMO scenarios.