2.2 Specimen preparation
Specific preparation process is as follows:
1) Take the water reducing agent, graphite, carbon fiber and cement
according to the design mix ratio, and pour them into the stirring pot
in batches and stir slowly for 180s;
2) Prepare a mixture of hydroxypropyl methylcellulose with water and add
it to the stirring pot, and then stir slowly for 120 s and then quickly
for 90 s;
3) The foaming agent solution (the mass ratio of foaming agent to water
is 1 : 40) is foamed by a foaming machine, and the prepared foam is
shown in figure 1. Add it to the mixing bowl and mix it well with the
slurry that has been stirred;
4) Test the wet density of foam concrete before pouring. The design wet
density of foam concrete is 600 kg/m3;
5) After 24 hours of pouring, the mold is removed and the specimens are
placed in cure chamber (20±2°C, RH ≥95%) to the desired age. The mix
ratio is shown in Table 3, and the ratio of water to cement is 0.5.