Mechanical Behavior of Fired-CSay Bricks from Stream Sediments under Uniaxial Compressive Loading

摘要

In the northeast of Thailand, raw material for fired-clay brick is obtained from fine stream sediments in the lower Nam Phong and upper Chi River sub-watersheds. Hundreds of brickyards are concentrated within the few square kilometers where the Nam Phong river merges with the Chi River. These brickyards supply rice husk ash (RHA) construction bricks for the entire northeast region. Technical study on the production of these bricks is currently limited, therefore, detailed studies on mechanical and chemical properties will enhance the understanding of the production process in order to improve their quality. The objective of this study is to investigate the production process and determine the compressive strength of fired-clay bricks produced in this industrial area. The study was conducted by preliminary investigation of the brickyards and production process. Brick samples as well as raw sediment materials were collected from 6 randomly selected locations for laboratory testing on physical, chemical, and mechanical properties. A total of 300 brick specimens were collected being 50 specimens from each location. The brick dimensions are roughly 5x5x15 cm with an average weight of about 680 g. X-Ray Diffractometry results show that the fired brick composition is approximately 90-98% quartz, 5-7% clay minerals, and less than 1% minor minerals. Mechanical behavior of the fired-clay bricks was evaluated by compressive loading of single brick units conducted under dry and submerged (with reverse osmosis water) conditions. The compressive strength of the brick unit is found to be proportional to its density with values in the range of about 0.4-1.2 MPa. Bricks with RHA to sediment ratio of 1:3 exhibit a higher average strength than that of other ratios.