Any of the Portland cement clinker, 20-50% volcanic ash mixed materials (such as volcanic ash, tuff, pumice, zeolite, diatomaceous earth, fly ash, burnt clay, burnt shale, coal gangue, etc.), appropriate amount of gypsum A mixture of ground hydraulic cementitious materials, called pozzolanic Portland cement, referred to as volcanic ash cement, code P·P. According to the Chinese standard, the amount of volcanic ash mixed material in cement is 20-50% by weight; granulated blast furnace slag which does not exceed 1/3 of the total blending amount of mixed materials is allowed to be replaced, instead of some volcanic ash mixed materials, after replacement The volcanic ash mixture in the cement shall not be less than 20%. Volcanic ash cement is divided into five numbers 275, 325, 425, 525 and 625. Compared with ordinary cement, volcanic ash cement has a small specific gravity, low hydration heat, good corrosion resistance, water requirement (the amount of water required to make the cement slurry reach a certain degree of fluidity) and dry shrinkage, and frost resistance is higher. Poor, early strength is low, but late strength development is faster, environmental conditions have a significant impact on the hydration and strength development of volcanic ash cement, and the humid environment is conducive to the development of cement strength. Volcanic ash cement is generally suitable for concrete works in underground, water and humid environments, and should not be used in dry environments, freeze-thaw cycles, dry-wet cycles, and projects requiring high early strength.
KelaiWood , https://www.kelaiwoodens.com