Geotechnical evaluation of clayey materials for quality burnt bricks

Abstract

Understanding of clayey materials properties continues to elude brick manufacturers, hence unsure of their application for brick making purposes. The raw materials were assessed geochemically, mineralogically, physically and technologically. The geochemical result showed that the fluxing oxides K 2 O, N 2 O, CaO, MgO and MnO are generally low in content with average abundance ranging from 0.06% to 1.78%. The Fe 2 O 3 content varies (4.8-25.5%) thus reflects heterogenous stability in tonality. Most of the studied samples have relatively high Al 2 O 3 content which suggest the bauxitic composition from which kaolinite minerals might have resulted from. The XRD analysis revealed the presence of kaolinite and chlorite as the major clay minerals while quartz, feldspar, talc and hornblende were present as non-clay minerals. For DTA, the threshold of new crystallization processes were attained at 1000 C. The SEM analysis revealed the presence of some stroma in all samples although with sizes >50 nm. These pores were suggested to constitute a capillary system where molten mineral occupy as temperature increases. The Atterberg's limit indicated that the studied materials are inorganic silts with high compressibility and organic clays properties since it plotted below the A-line of plasticity chart. The compressive strength (CS) for brick specimens made from kaolinite-rich material are relatively higher than chlorite-rich specimens. This was attributed to the ineffective pore connection within the kaolinite interstitial particles compared to the chlorite-rich specimen, hence increasing the density. The water absorption (WA) test on twenty brick specimens showed that the pore volume and capillarity for bricks which are chlorite-dominated were comparatively higher, thus absorbing more water molecules. These results revealed that majority of the studied clayey material are not suitable for double storey construction bricks but meet the requirements for single-storey construction when compared with SANS standards.

Methanogenesis Potentials: Insights from Mineralogical Diagenesis, SEM and FTIR Features of the Permian Mikambeni Shale of the Tuli Basin, Limpopo Province of South Africa

“…Samples were tightly mounted on oriented sample holder with very little pressure using black loading preparation technique using PANalytical X'Pert Pro-powder diffractometer equipped with X'Celerator detector coupled with receiving slits, variable divergence, and Fe-filtered Cu-Kα radiation at the Energy Centre CSIR Pretoria. While the receiving slit was positioned at 0.040 • , the counting area was from 2 to 80 • on a 2θ scale at 1.5 s [42]. The interstratified I/S minerals were measured on a less than 2 µm fraction of air-dried samples using Cu-Kα radiation [43].…”

Mineralogy and physic-chemical characteristics of indurated shale quarry waste and influence of firing temperature on their ceramic properties for incorporation in production of roofing tile

“…Grain size distribution has fundamental importance in the characterization of raw materials for traditional ceramic applications (Akintola et al 2020). It can indicate the plastic behavior and ring behavior exhibited by the raw material, as well as the mechanical strength of the red product.…”

“…It can indicate the plastic behavior and ring behavior exhibited by the raw material, as well as the mechanical strength of the red product. They control greatly technological parameters during drying and ring processes as sands are predictably reactive upon ring especially at lower temperature range (Akintola et al 2020). For ceramic products, the ner fraction of < 2 µm is of particular attention (Mahmoudi et al 2008).…”

“…4b) with those of the studied ISQW materials showed that they have oxides values very close outliers for earthenware and red clay body production. The alkali and alkaline earth elements (CaO+MgO+Fe 2 O 3 +Na 2 O+K 2 O; 12.3-16.4%) and in addition to the presence of illite and feldspar might guarantee a good fusibility for ceramic production (Tsozue et al 2017;Akintola et al 2020). The contents of the uxing oxides in the ISQW samples can favor su cient sintering during ring as vitreous phase formations is guaranteed.…”

“…The relevance of clays in economic (Kühnel, 1990;Ekosse 1994;Murray 2000) and technological development (Baccour et al 2009;Pavlova et al 2019;Kagonbe et al 2021), are due to their plasticity, inertness and stability, providing speci c properties including unique rheology, for speci c industrial use. Demand for clays as raw materials for commercial applications has risen sharply due to rapid increase in construction purposes owing to globalization and urbanization (Akintola et al 2020;Terrones-Saeta et al 2020). Such impressive infrastructural growth raised demand for clays as raw materials to an estimate of 230 million tons/ year (Stock 2012;Baraldi 2017).…”