In the compression test, when the density reaches or exceeds 90% of the maximum achievable density, the binder component in the electrode paste has sufficient fluidity to fill the electrode cylinder. After ensuring the compressibility, it is important to study the viscosity of the electrode paste. This is to evaluate the segregation performance of the electrode paste, because the greater the viscosity of the electrode paste, the less likely it will be segregation. Generally, viscosity is also related to bitumen content. The pitch in the electrode paste must provide sufficient plasticity to facilitate the compression of the electrode paste, but the pitch content must be as small as possible to avoid segregation.
At each temperature point, the penetration of the cone in the electrode paste is expressed as a percentage of displacement related to the total height of the cone. If the penetration value of the electrode paste is greater than 70%, it means that the viscosity of the electrode paste is small and segregation is easy to occur, so it is not recommended.