Temperature evolution during the compaction of calcium silicate hydrate powders using a compression calorimeter

Artikel i vetenskaplig tidskrift, 2020

Amorphous calcium silicate hydrate (CSH) undergoes contact-hardening property, i.e. the powder can be hardened by compression. A compression calorimeter was designed to determine the temperature evolution during the compaction of the powder. A platinum sensor (Pt100) was used as the temperature sensor and was positioned in the powder as well as in the compression die. A resolution of 0.01 °C with a sampling time of every second was used to monitor the temperature. Both theoretical calculation and simulations by COMSOL multiphysics showed that the device reliably evaluated the temperature during the compaction of CSH powders. The measurement was taken under semi-adiabatic conditions. The temperature profiles obtained from the measurement revealed the compression process and bonding development during the compaction of the powders. Finally, a linear relationship was observed between the compressive strength and the maximum temperature increase. This provides insight into the contact-hardening mechanism during the compaction of CSH powders.