Aggregate types acid resistant

Humic acids are soluble in weak alkaline solutions and are essentially insoluble in water and mineral acids. They may be precipitated from solution by the action of mineral acids and bivalent or trivalent cations, however, they are fairly resistant to the acid hydrolysis. They are dark spherocol-loids with a cross-linked structure which plays a part in their high sorption capacity. They exhibit different degrees of a tendency to aggregation and very different degrees of dispersion. In comparison with other types of natural organic substances, the humic acids are characterized by their extraordinary stability in the soil. This stability is due to their ability to form organomineraJ complexes, particularly with clay minerals and with aluminium and iron hydroxides. 

Sodium silicate mortars are available as either two component systems, which consist of the liquid sodium solution and the filler powder containing settling agents and selected aggregates, or they may be a one part system in powder form to be mixed with water when used. There are some differences in the chemical resistance between the two types. The differences in the chemical resistance of the two types of mortars are shown in Table 7.7. Sodium silicate mortars are useful in the pH range of 0-6, except where sulfuric acid exposures exist in the vapor phase, wet-dry exposures, or in concentrations above 93%. 

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