Engineering Properties of Adobe Brick for Earth Structures
2014 年 5 巻 2 号 p. 41-46
詳細
2014 年 5 巻 2 号 p. 41-46
The aim of this research is to investigate basic engineering properties of soil mixture materials and adobe bricks for earth structures. The soil mixture materials consist of soil, sand and rice husks. Samples of soil mixture materials and adobe bricks were collected from three villages (i.e. sources) in northeastern Thailand with adobe brick earth structures. The raw materials obtained from the three sources are: (1) soil, sand and rice husks from Baan Sikha Thai village of Nakhon Ratchasima province, (2) soil and rice husks from Baan Sai Rung village of Chaiyaphum province, and (3) soil and rice husks from Baan Thep Pana village of the province of Chaiyaphum. The physical properties of soil mixture materials and the mechanical characteristics in terms of adobe bricks and wall bearing strength (prism strength) were carried out. According to ASTM D-2487 of the Unified Soil Classification System, the soils from the three sources are of sand-poorly graded (SP) type. PI of soils and the horizontal compressive strength (σc) of adobe bricks from the first, second and third sources were 7.93, 6.02 and 2.88%; and 21.76, 15.76 and 13.48 kg/cm2 (ksc), respectively. The findings indicate a positive relationship between plasticity index (PI) from Atterberg’s limits test and horizontal σc. A comparison was made between the horizontal σc of adobe bricks of three sources and those specified in the Uniform Building Code (UBC) Standard 21-1. The horizontal σc of the first, second and third sources relative to the UBC standard (17.6 ksc) were 21.76, 15.76 and 13.48 ksc, equivalent to 123.65%, 89.57% and 76.57% of the standard, respectively. The horizontal flexural strengths (fb) of adobe bricks from the three sources were 5.86, 3.24 and 4.27 ksc. Thus, no indefinite relationship exists between fb and PI as well as horizontal σc. In addition, a comparison between the horizontal σc of adobe bricks from three sources and the wall bearing strength (prism strength) of walls made from the identical three sources was performed. The wall bearing strength values of the first, second and third sources were 9.44, 6.39 and 3.63 ksc, respectively. The results show a positive relationship of prism strength to PI and to horizontal σc. The performance of adobe bricks in terms of greater strength and lower shrinkage could be enhanced by inclusion of appropriate quantities of sand and rice husks in the mixture.
