A Comparison of Thermal and Mechanical Properties of Clay Bricks Prepared with Three Different Pore‐Forming Additives: Vermiculite, Wood Ash, and Sawdust

Abstract

The thermal and mechanical properties of fired clay bricks containing three different pore‐forming additives at comparable concentrations (~25 wt %) were investigated. The additives included three types: inorganic (vermiculite), organic (sawdust), and ash (wood ash). These additives have very different pore‐forming mechanisms during the firing process and leave very different residuals in the fired brick. Brick properties are affected by the brick forming process (e.g., the raw materials, forming, drying, and firing processes), and so there is wide variation in the effects of additives on brick properties in the published literature. Therefore, the objective of this effort was to compare selected properties of fired clay bricks with different types of additives, while keeping the brick forming process the same. In this study, the trends in bulk density, porosity, water absorption, compressive strength, and thermal conductivity with incorporation of additives in clay bricks support those that have been published. However, the thermal conductivity of the brick with 25 wt % wood ash was comparable to that for the brick without additives, despite having greater porosity and lower bulk density. This supports that both the pores formed during the firing process and the residuals of the additives significantly impact the brick properties. © 2019 American Institute of Chemical Engineers Environ Prog, 38: e13150, 2019

Immobilization of High-Leaded Cathode Ray Tube Glass in Fired Clay Bricks by Recycling

“…Obviously, the immobilization of waste CRT glass in the clay bricks influences the porosity and bulk density of the clay bricks. Greater porosities were generally achieved as the proportions of the glass were increased across the three particle sizes in agreement with the study of Beal et al (2019), but decreased down the trend as more waste CRT glass were added. From the result in the Table 4, the average apparent porosity of 2wt% CRT-clay composition of the particle sizes was in the order of 17.1±0.87 < 20.4±0.92 < 20.4±0.40 in comparison with 18.2±0.18 of control clay sample value.…”

“…The results of total linear shrinkage of CRT glass incorporated in clay bricks obtained from drying and frying at temperature of 800•c for the three particle sizes of less than 0.6mm, 1.0mm and 2.0mm were presented in Table 3. Beal et al (2019) reported that linear shrinkage is an important property of clay bricks while high linear shrinkage could cause cracks, stress and breaks the brick as water evaporates the bricks during drying and firing as a consequent shrink the clay bricks. From the result, it can be shown that the minimum average shrinkage was observed at 2% (3.53±1.42), 4% (3.87±1.58) and 6% (5.99±0.17) in the particle size of less than 1.0mm, 0.6mm and 2.0mm respectively.…”

Effects of expanded vermiculite on the properties of fired bricks from water treatment sludge

“…Also, it is resistant to temperatures ranging from 260–1200°C. Due to the remarkable physical characteristics of EV, various researchers have attempted to incorporate the light‐weight material in the production of fired clay bricks to investigate the corresponding physical and mechanical properties 19–27 …”

“…The thermal conductivity of the controlled bricks was measured at 1.1 W/m‐K and decreased to 0.85 W/m‐K, and 0.80 W/m‐K with the addition of 8% expanded perlite and EV. Beal et al 26 . studied the effect of 20% EV by wt.…”

Eco-Friendly Fired Brick Produced from Industrial Ash and Natural Clay: A Study of Waste Reuse

“…The desirable characteristics of bricks include uniformity in color, size and shape, and they should be free from cracks and flaws. In addition, the compressive strength of bricks should be suitable for their intended use [ 49 ].…”