Proposed stress block for no coarse-aggregate concrete

Concrete is one of the materials in construction that continues to develop in strength and efficiency. Since most areas in Indonesia are vulnerable to earthquakes, the building structures must be more resistant to seismic forces. Increasing the concrete's strength might reduce the building structure's dimensions and weight, which will also reduced the earthquake force. One example of high-strength concrete is reactive powder concrete (RPC), an innovative concrete with small particle materials to fill in the space within the concrete so it can strengthen the concrete. Despite the advantage, there is still a lack of design provisions for this type of concrete. This research was conducted to analyze the stress-strain diagram curve and the compressive stress block for no-coarse aggregtae concrete. In this research, compression tests have been carried out on 100 mm - 200 mm cylinder samples with concrete compressive strength ranges from 28 to 76 N/mm2. Test results indicate that the actual curve of the stress-strain relationship for concrete without coarse aggregate is almost linear and shaped like a triangle with the maximum strain ranges from 0.006 to 0.008. The energy per unit volume ranges from 0.1175 to 0.3658 N/mm2 and the average force capture point is 0.62626 units. Based on the test results, compression stress block for no-coarse aggregtae concrete are proposed.