A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks

Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water.