# Bricks Using Clay Mixed with Powder and Ashes from Lignocellulosic Biomass: A Review
## 6 Unfired Clay Bricks Reinforced by Lignocellulosic Biomass Ash
Different amounts of distilled water (15% and 20%) and calcined OBFA (OBFA/c) (10%, 20%, 30%, and 40%) were used to prepare a group of samples. It was determined that mechanical and physical tests produced the best results for the 20% distilled water bricks. Indeed, at low water percentages, OBFA cannot dissolve properly, however, at higher values of biomass fly ash, a better dissolution could be observed due to the polymerization reaction improvement. Additionally, samples made with 30% OBFA/c and 20% distilled water demonstrate promising physical and mechanical qualities, with a compressive strength of 58.98 Mpa. However, a decrease in compressive strength was noted when OBFA incorporation exceeded 30% by weight. In the same study, [PERSON] [90] investigated the feasibility of producing geopolymer using alperoujo (BBA) (a by-product of oil composed of solid parts of olives and vegetable fats) as an alkaline activator and biomass clinker from the combustion of almond shells and Chamotte (C) as a source of aluminosilicate. The physical and aesthetic qualities of this geopolymer are comparable to those of conventional bricks. The compressive strength reaches a maximum value of 59.2 MPa for the ideal mixture of 40% chamotte (C) and 60% BBA. It is not possible to make a comparison in these studies. In fact, several factors, including the amount of reactive phases, the chemical makeup and types of aluminosilicate sources, the nature and concentration of the alkali silicate, the curing regimes, the fillers or additive content, as well as the water content, all have an impact on the formation of geopolymer bricks. * The influence of the clay calcination temperature To increase the reactivity of the clay used in the geopolymerization reaction, the clay must be calcined, which is a crucial step in the production of geopolymer bricks. The heat treatment transforms the crystalline phases of the clay into amorphous phases more reactive which contributes to the geoplymerization reaction and determines the final properties of the geopolymers. The optimal activation temperature depends on the mineralogical composition of the material. Thermogravimetric analysis (TGA) is commonly used to determine this ideal calcination temperature. The activation temperature must be at a temperature above the dehydroxylation peak observed on the derivative of the TGA curve or the differential thermal analysis (DTA) curve showing a downward pointing peak during dehydroxylation (endothermic reaction). One must determine the temperature that indicates the end of the peak on the DTG or DTA curve associated with the loss of \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Oxide** & **SBA** & **SCBA** & **RHA** & **BA** & **RHA** & **BBA** & **BBA** & **OPFA** & **OBFA/c** \\
**Cotenant** & [77] & [80] & [83] & [81] & [79] & [90] & [91] & [88] & [89] \\ \hline SiO\({}_{2}\) & 35.17 & 51.66 & 89.08 & 35.17 & 93.15 & 11.21 & 46.10 & 1.86 & 56.35 \\ Al\({}_{2}\)O\({}_{3}\) & 0.28 & 9.92 & 1.75 & 0.28 & 0.21 & 2.57 & 12.04 & 0.38 & 14.96 \\ FeO\({}_{3}\) & 5.22 & 2.32 & 0.78 & 5.22 & 0.21 & 1.33 & 4.78 & 0.67 & 6.07 \\ CaO & 2.07 & 2.59 & 1.29 & 2.07 & 0.41 & 11.10 & 19.65 & 5.33 & 9.15 \\ MgO & 0.91 & 1.44 & 0.64 & 0.91 & 0.45 & 4.21 & 3.71 & 0.81 & 3.05 \\ Na\({}_{2}\)O & 0.01 & - & 0.85 & 0.01 & - & 0.22 & 0.78 & 0.19 & 0.59 \\ K\({}_{2}\)O & 3.75 & 2.10 & 1.38 & 3.75 & 22.31 & 23.91 & 4.59 & 52.1 & 4.52 \\ TiO\({}_{2}\) & 0.02 & 0.74 & - & - & - & 0.12 & 0.83 & 0.05 & 0.74 \\ P\({}_{2}\)O\({}_{5}\) & 1.05 & 0.90 & 0.62 & - & - & 3.58 & 1.12 & 1.62 & 0.15 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The chemical make-up of various lignocellulosic biomass ashes used in the production of unfired clay bricks. Figure 9: Compressive strength for geopolymer bricks: 70% CC–30% OPFA [88], 70% CH–30% OBFA [89], 40% C–60% BBA [90], GMK-BBA-WC [91]. hydroxyls from the used clay and before the peak showing the structural reorganization of the mineral during recrystallization.