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Earth bricks could contribute to alleviate the housing shortage in the world, thanks to their low cost, easy production, and low environmental impact. However, to manufacture bricks with required properties, many raw soils must be ameliorated. In Central and Eastern Africa, the waste water of the cassava processing is used to improve earth brick mechanical properties. This technique is interesting, because it is sustainable, low-cost and easy to implement. But, studies on this stabilization method are scarce, in particular on the drying kinetics of these bricks. Now, it is important to know the drying duration, because the earth brick’s strength is strongly correlated to its moisture content. Thus, this study aims to quantify and to model the effect of adding cassava flour gel and amylopectin on the drying kinetics of earth bricks. Depending on the soil nature, the drying duration decreases from 7% to 25% for a stabilizer content of 20%. For the five models used, the coefficient of determination is superior to 0.997 and the chi square is inferior to 3 × 10
^{−4}. In average, the best model is Khazaei, followed in order by Avrami-Page, diffusion, Yong and Peleg. The effective coefficient of diffusion of water is about 4 × 10
^{−5} m
⋅s
^{−2}. The parameter T of the Khazaei’s model is strongly correlated to the drying duration and the stabilizer content, and their relationships have been deduced.

Although the housing is one of the basic human needs [^{th}, 14^{th}, 21^{st} and 28^{th} days, as for concrete. To optimize the production of bricks, it is essential to know exactly the effect of adding the stabilizer on the drying kinetics of bricks, because the presence of water affects strongly the bricks’ mechanical properties. But little is known on the drying kinetics of earth stabilized bricks. This lack is particularly true for stabilized bricks with starch. In addition, cassava starch is a mixture of amylose and amylopectin. The effect of the components on the brick properties is not yet known.

The objective of this work is to assess the effect of adding the cassava flour gel or amylopectin on the drying kinetics of earth brick and to model the kinetics. For this purpose, a natural clayey soil, and Cubitermes sp. and Macrotermes sp. mound soils had been used as raw materials. Mound termite soils are often used by traditional brickmakers instead of natural clayey soils, because they are usually more clayey than surrounding soils. Besides, five empirical or semi-empirical drying models had been chosen among the most used for modeling the drying kinetics.

The termite mound soils were obtained by crushing uninhabited termite mounds. After crushing, soil grains larger than 2 mm were eliminated by sieving. The Cubitermes sp. mounds were collected in the savanna around Ngo in the south of Congo, while the Macrotermes sp. mounds were collected at Kombé, in the south of Brazzaville. The natural clayey soil was collected in a brickwork quarry, at Dolisie.

The plasticity of the soils was estimated through the Atterberg’s limits according to the NF 94,051 standard [

The cassava flour gel was prepared by heating the cassava flour in water until the total disappearance of free water. The cassava flour has been obtained by finely molding about 50 kg of dried cassava tubers. These dried tubers were bought in a local market and are usually used for the human feeding.

To make the bricks, after mixing the gel, the soil and tap water in the good proportions, the mixture was molded and compressed with a mechanical press at 6 MPa. The tap water content used for the mixture is the optimum moisture content (OMC) of the soil determined by the Proctor test. The Proctor test was performed according to the NF 94,093 standard [

The brick’s curing kinetics was monitored by following the evolution of the brick’s mass. A brick was considered dried when the variation of their mass during three days was less than 2%.

Five empirical or semi-empirical drying kinetics models had been used: the diffusion model, the Weibull model, the Peleg model, the modified Kazaei model and the Unified expression of Yong et al. Besides, the concept of the characteristic drying curve has been applied on the drying kinetics.

Soil characteristics | N | C | M |
---|---|---|---|

Clay (%) | 18.7 | 25 | 20 |

Silt (%) | 40.7 | 25 | 20 |

Sand (%) | 40.6 | 50 | 60 |

W_{L} (%) | 47.2 | 11.6 | 28 |

Wp (%) | 25.4 | 2.1 | 11.6 |

PI (%) | 21.8 | 9.5 | 16.4 |

ω_{omc} (%) | 17.8 | 15.2 | 11 |

γ (t/m^{3}) | 1.54 | 1.72 | 1.98 |

OM (%) | 1.93 | 5.00 | 0.46 |

The Page model (Equation (1)) has the same form as Avrami’s law (crystallization kinetics) or the Weibull model (ultimate strength for brittle materials) [

M r ( t ) = exp ( − k t n ) ; α = k − 1 / n (1)

M_{r}(t) is the removable water content; α is called the scale parameter or the time to remove 63.2% of the removable water, and thus it is related to the drying speed. n is the shape parameter, and it is superior to 1 for drying kinetics where the drying rate increases firstly until its maximum and then decreases continuously until 0 (equilibrium). On the contrary, if the drying process is governed by the moisture diffusion, the n value is less or equal to 1. This model has been used to simulate vegetables’ drying kinetics, crystallization kinetics and the failure of brittle materials [

The diffusion model (Equation (2)) is the simplified solution of the Fick’s law [

M r ( t ) = a exp ( − k t ) + ( 1 − a ) exp ( − k b t ) (2)

a, b and k are adjusted parameters. For infinite plates, k is equal to Dπ^{2}/4L^{2}, with D the effective coefficient of diffusion, L the half-thickness of the plate. This model has been used for several products.

The Peleg model has been modified to express the moisture ratio instead the water mass in the product (Equation (3)) [

M r ( t ) = 1 − t / ( a + b t ) (3)

a and b are adjusted parameters, but a is the inverse of the initial drying rate.

Equation (4) is the modified Khazaei model [

M r ( t ) = 1 − a ( 1 − exp ( − t / T ) ) − b t (4)

a, k and b are adjustable parameters. The inverse of T has the same meaning as k in the Page model, that is, it is equal to the duration to remove 63.2% of the removable moisture. The parameter b is equal to the drying rate near the end of the drying process. This model appears as a correction of the Page model.

The unified expression of Yong et al. (Equation (5)) [

M r ( t ) = c t − μ exp ( − t / T ) (5)

U ( t ) = ( t μ M r ) / c = exp ( − t / T ) (6)

c, μ and T are adjusted parameters.

The concept of the characteristic drying curve assumes that the normalized drying rate f (f = v(t)/v(0), v(t) is the drying rate at the time t) depends only on the moisture content and the nature of the material [_{r} should be the same.

The determination of the models’ parameters for each drying curve is performed with the Origin Pro 8 software. The fitting goodness of the models is estimated through the reduced chi-square (χ^{2}) and the coefficient of determination (R^{2}). The best model has the lowest χ^{2} and the highest R^{2}. Besides, these models are compared through the Aike’s Information criterium which takes into account the number of parameters in the model. According to the AIC, for the same precision, the best model is that has the lowest number of parameters.

The drying kinetics curves of the compressed and stabilized clayey soil bricks as well as those of the Cubitermes mound soil and the Macrotermes mound soil are reported in

For non-stabilized bricks, it seems that the variation of the clay percentage does not influence significantly the drying duration. Indeed, all non-stabilized bricks have the same drying duration of 28 days in average. But this duration should be considered as the minimum owing the fact that bricks used in this study are smaller than those used in construction. Besides, the incorporation of the cassava flour gel or amylopectin in the soil reduces the drying duration from 2 to 7 days depending on the soil, that is, a decrease of 7% - 25% in comparison with the non-stabilized brick. The greatest reduction is obtained with termite mound soils. In average, the reduction obtained by stabilizing with cassava flour gel is greater than that with amylopectin. This reduction of the drying duration could be explained by the higher drying rate of the cassava flour gel and amylopectin (about one week) in comparison with that of non-stabilized bricks (about one month).

The statistical parameters of this modeling are reported in ^{2}) and the Chi square (χ^{2}) are equal to 0.997 ± 0.002 and (3 ± 2) × 10^{−4} for the Yong model, 0.998 ± 0.002 and (2 ± 2) × 10^{−4} for the Avrami-Page model, 0.986 ± 0.009 and (14 ± 12) × 10^{−4} for the Peleg model, 0.999 ± 0.001 and (1 ± 1) × 10^{−4} for the Khazaei model, and 0.997 ± 0.003 and (2 ± 2) × 10^{−4} for the diffusion model.

The ranking of the models depends on the statistical parameter used as criteria (^{2} ≤ 1, and R^{2} = 1 for one third of the curves), followed in order by Avrami-Page, Diffusion, Yong and Peleg. In particular, it could be noticed that even for the AIC criterion which favors model with fewer parameters, the Khazaei’s model remains the best despite its four parameters, except for Macrotermes mound soil bricks.

The values of the models’ parameters are listed in

As already mentioned in the chapter Materials and methods, the values of the effective coefficient of diffusion of water (D_{ef}) had been deduced from the parameter k of the diffusion model. These values are listed in

For all earth bricks, adding cassava flour gel or amylopectin increases the value of the effective coefficient of diffusion of the bricks. For the same percentage, in average, the increase in value due to cassava flour gel is higher than that due

CEB | Yong | Avrami-Page | Peleg | Khazaei | Diffusion | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|

R^{2} | Χ^{2} (10^{−4}) | AIC | R^{2} | Χ^{2} (10^{−4}) | AIC | R^{2} | Χ^{2} (10^{−4}) | AIC | R^{2} | Χ^{2} (10^{−4}) | AIC | R^{2} | Χ^{2} (10^{−4}) | AIC | |

N0 | 0.993 | 10.1 | −102 | 0.998 | 2.6 | −126 | 0.985 | 21.3 | −93 | 0.999 | 1.1 | −134 | 0.995 | 7.0 | −108 |

NS5 | 0.996 | 4.5 | −115 | 0.998 | 2.0 | −131 | 0.986 | 16.3 | −97 | 0.998 | 2.3 | −123 | 0.996 | 4.9 | −114 |

NS10 | 0.995 | 5.9 | −111 | 0.997 | 3.5 | −121 | 0.984 | 17.6 | −96 | 0.997 | 4.0 | −114 | 0.996 | 4.8 | −114 |

NS15 | 0.997 | 4.2 | −116 | 0.998 | 2.7 | −126 | 0.966 | 41.7 | −82 | 0.999 | 1.1 | −135 | 0.992 | 0.0 | −100 |

NS20 | 0.998 | 2.1 | −118 | 0.999 | 1.3 | −128 | 0.948 | 51.9 | −73 | 1.000 | 0.0 | −135 | 0.987 | 0.0 | −90 |

NA5 | 0.996 | 4.6 | −170 | 0.998 | 1.6 | −196 | 0.986 | 14.0 | −146 | 0.999 | 0.9 | −205 | 0.998 | 2.4 | −184 |

NA10 | 0.998 | 1.9 | −155 | 0.999 | 1.2 | −166 | 0.998 | 1.4 | −163 | 0.999 | 0.9 | −168 | 0.999 | 0.9 | −170 |

NA15 | 0.999 | 0.8 | −176 | 0.999 | 0.7 | −181 | 0.998 | 2.0 | −137 | 0.999 | 0.5 | −174 | 1.000 | 0.4 | −177 |

NA20 | 0.999 | 0.6 | −172 | 0.999 | 0.5 | −175 | 0.994 | 5.6 | −157 | 0.999 | 0.6 | −178 | 0.999 | 0.6 | −183 |

C0 | 0.993 | 8.1 | −128 | 0.994 | 6.6 | −134 | 0.990 | 10.6 | −125 | 0.998 | 2.0 | −152 | 0.996 | 4.1 | −141 |

CS5 | 0.999 | 1.8 | −148 | 0.999 | 1.6 | −151 | 0.974 | 29.1 | −100 | 0.999 | 1.3 | −150 | 0.996 | 5.2 | −128 |

CS10 | 0.999 | 1.2 | −154 | 0.999 | 1.3 | −155 | 0.984 | 16.9 | −109 | 0.999 | 1.1 | −154 | 0.998 | 2.1 | −145 |

CS15 | 0.996 | 3.1 | −121 | 0.997 | 2.5 | −127 | 0.989 | 8.5 | −107 | 1.000 | 0.4 | −151 | 0.999 | 1.2 | −137 |

CS20 | 0.998 | 2.3 | −117 | 0.998 | 2.1 | −121 | 0.984 | 14.5 | −92 | 1.000 | 0.3 | −146 | 0.999 | 0.8 | −132 |

CA5 | 0.999 | 1.5 | −186 | 0.999 | 1.1 | −195 | 0.989 | 11.2 | −144 | 1.000 | 5.7 | −206 | 0.999 | 0.7 | −202 |

CA10 | 1.000 | 0.5 | −211 | 0.999 | 0.6 | −208 | 0.988 | 10.7 | −145 | 1.000 | 0.2 | −232 | 0.999 | 0.7 | −204 |

CA15 | 0.997 | 2.1 | −153 | 0.997 | 2.3 | −153 | 0.977 | 16.9 | −116 | 1.000 | 0.4 | −185 | 0.996 | 2.8 | −148 |

CA20 | 0.999 | 1.1 | −175 | 0.999 | 1.0 | −180 | 0.981 | 14.4 | −125 | 0.999 | 1.0 | −175 | 0.999 | 1.2 | −173 |

M0 | 0.998 | 1.7 | −183 | 0.998 | 1.3 | −191 | 0.990 | 8.0 | −152 | 0.999 | 0.5 | −207 | 0.999 | 0.8 | −201 |

MS5 | 0.997 | 2.3 | −178 | 0.998 | 1.4 | −191 | 0.993 | 5.5 | −160 | 0.999 | 0.9 | −195 | 0.999 | 1.0 | −196 |

MS10 | 0.997 | 1.9 | −190 | 0.999 | 0.7 | −216 | 0.997 | 2.1 | −190 | 0.999 | 0.6 | −215 | 1.000 | 0.3 | −235 |

MS15 | 0.997 | 1.8 | −174 | 0.999 | 0.4 | −187 | 0.999 | 0.5 | −146 | 1.000 | 0.1 | −201 | 1.000 | 0.2 | −189 |

MS20 | 0.999 | 0.7 | −156 | 0.999 | 0.4 | −156 | 0.994 | 3.5 | −181 | 1.000 | 0.3 | −217 | 1.000 | 0.2 | −203 |

MA5 | 0.999 | 0.6 | −156 | 1.000 | 0.5 | −164 | 0.991 | 9.0 | −114 | 1.000 | 0.5 | −159 | 1.000 | 0.4 | −163 |

MA10 | 0.994 | 6.6 | −117 | 0.993 | 7.3 | −117 | 0.976 | 23.7 | −97 | 0.995 | 0.5 | −117 | 0.993 | 7.5 | −114 |

MA15 | 0.992 | 5.7 | −142 | 0.994 | 4.1 | −150 | 0.990 | 6.9 | −140 | 0.998 | 1.4 | −167 | 0.998 | 1.4 | −170 |

MA20 | 0.995 | 4.6 | −115 | 0.998 | 1.9 | −131 | 0.997 | 2.3 | −128 | 0.999 | 1.3 | −132 | 0.999 | 0.6 | −147 |

Rank | N | C | M | ||||||
---|---|---|---|---|---|---|---|---|---|

R^{2} | χ^{2} | AIC | R^{2} | χ^{2} | AIC | R^{2} | χ^{2} | AIC | |

1 | Kh | Kh | Kh | Kh | Kh | Kh | Di | Kh | Di |

2 | Av | Av | Av | Di | Di | Di | Kh | Av | Av |

3 | Yo | Yo | Yo | Av | Av | Av | Av | Di | Kh |

4 | Di | Di | Di | Yo | Yo | Yo | Yo | Yo | Yo |

5 | Pe | Pe | Pe | Pe | Pe | Pe | Pe | Pe | Pe |

CEB | Khazaei | Avrami-Page | Diffusion | Yong | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|

a | T | n | b (10^{−4}) | k | n | a | k | b | C | µ | dc | |

N0 | 1.16 | 8.44 | 1.16 | −54 | 0.08 | 1.25 | −36.14 | 0.08 | 1.01 | 1.10 | −0.01 | 6.25 |

NS5 | 1.04 | 6.77 | 1.16 | −14 | 0.11 | 1.20 | −29.74 | 0.10 | 1.01 | 1.08 | −0.01 | 5.74 |

NS10 | 1.07 | 6.12 | 1.10 | −26 | 0.14 | 1.15 | −32.62 | 0.12 | 1.01 | 1.05 | −0.01 | 5.21 |

NS15 | 0.95 | 4.33 | 1.21 | 21 | 0.17 | 1.15 | −16.13 | 0.15 | 1.02 | 1.10 | −0.01 | 4.08 |

NS20 | 0.96 | 3.68 | 1.41 | 17 | 0.17 | 1.31 | −41.65 | 0.18 | 1.01 | 1.33 | −0.04 | 2.82 |

NA5 | 1.16 | 7.94 | 1.10 | −51 | 0.10 | 1.19 | −14.44 | 0.09 | 1.03 | 1.08 | −0.01 | 5.93 |

NA10 | 1.05 | 5.69 | 0.97 | −15 | 0.19 | 1.01 | −0.01 | 0.03 | 7.21 | 0.99 | 0.00 | 5.29 |

NA15 | 1.01 | 4.27 | 0.91 | −0.3 | 0.27 | 0.92 | 0.92 | 0.21 | 6.49 | 0.94 | 0.01 | 4.65 |

NA20 | 1.03 | 3.92 | 0.87 | −9 | 0.31 | 0.89 | 0.89 | 0.23 | 7.83 | 0.91 | 0.01 | 4.29 |

C0 | 1.32 | 9.17 | 0.87 | −81 | 0.16 | 0.99 | −0.01 | 0.01 | 23.53 | 0.97 | 0.00 | 6.41 |

CS5 | 0.97 | 5.14 | 0.99 | 14 | 0.19 | 0.99 | 0.00 | 0.01 | 30.10 | 1.00 | 0.00 | 5.33 |

CS10 | 0.95 | 4.18 | 1.08 | 20 | 0.21 | 1.04 | −11.38 | 0.19 | 1.01 | 1.03 | 0.00 | 4.30 |

CS15 | 0.93 | 3.14 | 1.13 | 30 | 0.29 | 0.97 | 0.10 | 0.13 | 2.42 | 1.00 | 0.00 | 3.55 |

CS20 | 0.96 | 2.48 | 1.03 | 18 | 0.39 | 0.96 | 0.11 | 0.15 | 2.73 | 0.98 | 0.00 | 2.80 |

CA5 | 1.06 | 6.25 | 0.97 | −18 | 0.17 | 1.02 | −0.06 | 0.07 | 2.49 | 1.00 | 0.00 | 5.65 |

CA10 | 0.95 | 4.22 | 1.09 | 18 | 0.21 | 1.03 | 0.00 | 0.06 | 4.01 | 1.03 | 0.00 | 4.38 |

CA15 | 0.96 | 3.84 | 1.20 | 14 | 0.21 | 1.11 | −20.51 | 0.20 | 1.01 | 1.12 | −0.02 | 3.54 |

CA20 | 1.00 | 3.17 | 1.02 | 0.8 | 0.29 | 1.05 | −5.13 | 0.26 | 1.03 | 1.02 | 0.00 | 3.12 |

M0 | 0.99 | 4.18 | 0.92 | 6 | 0.26 | 0.92 | 0.82 | 0.20 | 3.10 | 0.18 | 0.61 | 0.32 |

MS5 | 0.95 | 3.10 | 0.92 | 19 | 0.35 | 0.86 | 0.46 | 0.18 | 2.70 | 0.89 | 0.02 | 4.09 |

MS10 | 0.97 | 2.63 | 0.84 | 12 | 0.44 | 0.80 | 0.49 | 0.20 | 3.54 | 0.85 | 0.02 | 3.66 |

MS15 | 0.98 | 1.78 | 0.70 | 7 | 0.66 | 0.68 | 0.39 | 0.21 | 5.24 | 0.68 | 0.06 | 3.48 |

MS20 | 0.98 | 1.81 | 0.89 | 9 | 0.61 | 0.82 | 0.25 | 0.24 | 2.78 | 0.77 | 0.04 | 2.56 |

MA5 | 0.97 | 3.42 | 0.93 | 10 | 0.31 | 0.91 | 0.63 | 0.21 | 2.38 | 0.93 | 0.01 | 3.98 |

MA10 | 0.88 | 2.52 | 1.28 | 48 | 0.32 | 0.97 | 0.16 | 0.14 | 2.63 | 1.04 | 0.00 | 3.08 |

MA15 | 0.96 | 2.13 | 0.91 | 17 | 0.50 | 0.82 | 0.36 | 0.20 | 3.26 | 0.87 | 0.02 | 2.86 |

MA20 | 0.96 | 1.75 | 0.87 | 20 | 0.60 | 0.79 | 0.33 | 0.23 | 3.44 | 0.79 | 0.03 | 2.65 |

to amylopectin. Besides, the effective coefficient of diffusion is highest for Macrotermes mound soil bricks, followed in order by Cubitermes mound soil ones, and natural clayey soil ones. The increase of the effective coefficient of diffusion with the addition of the cassava flour gel or amylopectin is the consequence of the fast-drying kinetics of these products in comparison to that of non-stabilized soils. Care must be taken for comparing values of the coefficient of diffusion because they depend on the material moisture content, the temperature and the method used to measure them. Data on drying of earth bricks are scarce. Our

CEB | D_{ef flour} (10^{−5} m^{2}/s) | D_{ef amylo} (10^{−5} m^{2}/s) |
---|---|---|

M0 | 3.88 | 3.88 |

M5 | 5.24 | 4.75 |

M10 | 6.18 | 6.44 |

M15 | 9.10 | 7.60 |

M20 | 8.96 | 9.26 |

C0 | 1.77 | 1.77 |

C5 | 3.16 | 2.60 |

C10 | 3.88 | 3.84 |

C15 | 5.16 | 4.23 |

C20 | 6.56 | 5.11 |

N0 | 1.92 | 1.92 |

N5 | 2.40 | 2.04 |

N10 | 2.65 | 2.85 |

N15 | 3.75 | 3.80 |

N20 | 4.41 | 4.14 |

values are higher than those of tropical woods, vegetables, and plant fibers [

_{r}, with a coefficient of determination R^{2} = 0.99 and a standard deviation SD = 0.02. These curves look like those predicted for thick samples and slow drying by Keey and Suzuki [_{r}, instead of the concave shape, could be explained by the absence of the constant drying rate phase in these drying kinetics curves. Thus, the ratio v(t)/v(0) decreases continuously. On other words, earth bricks are not saturated with water. This result is consistent with the fact that these drying kinetics are driven by water diffusion.

Besides, the unified expression of Yong et al. fits well all drying kinetics curves of these drying curves.

The Khazaei’s model, the Avrami-Page, and the diffusional models are all exponential. When the time exponent n = 1 as for these drying kinetics, the coefficients K of the diffusional model, and that of the Avrami-Page model, and the coefficient 1/T of the Kharzaei one have the same function. Thus, in the sequel, only the correlations between T and the stabilizer content, and the drying duration are reported because this model is the best for these drying kinetics.

CEB | T vs duration | R^{2} | T vs stabilizer content | R^{2} |
---|---|---|---|---|

NA | 0.46t^{2} ? 23t + 283 | 0.98 | 0.002x^{3} ? 0.05x^{2} + 0.09x + 8.5 | 0.99 |

CA | 0.36t^{2} − 18t + 227 | 0.98 | 0.02x^{2} − 0.64x + 9.1 | 0.98 |

MA | 0.34t − 6 | 0.98 | −0.12x + 4 | 0.97 |

NS | 1.4t − 32 | 0.97 | −0.24x + 8.26 | 0.97 |

CS | 0.17t^{2} − 7.8 + 92 | 0.98 | 0.02x^{2} − 0.69 + 8.8 | 0.97 |

MS | 0.13t^{2} − 6t + 77 | 0.98 | 0.01x^{2} − 0.23x + 4.2 | 0.98 |

Relationships between T and the stabilizer content and the drying duration are reported in

The aim of this work was to assess the effect of adding the cassava flour gel and the amylopectin in earth bricks on their drying kinetics and to model the drying kinetics. The results show that: 1) the drying duration decreases with the increasing of the stabilizer content. For the content of 20% and in comparison to non-stabilized bricks, this decrease varies from 2 to 7 days depending on the soil and the stabilizer. Termite mound soils have the greatest decrease, and the cassava flour gel is more effective than amylopectin; 2) all the five models used fit well the earth brick drying kinetics, with the coefficient of determination higher than 0.997 and the chi square inferior to 3 × 10^{−4}. The Khazaei’s model is the best, followed in order by the diffusion, the Avrami-Page, the Yong and the Peleg ones. The characteristic drying curve of these earth bricks is nearly linear (f = M_{r}). The average value of the coefficient of diffusion deduced is 4 × 10^{−5} m∙s^{−2}. The parameter T of the Khazaei’s model is strongly correlated to the drying duration and the stabilizer content.

The authors declare no conflicts of interest regarding the publication of this paper.

Ngoulou, M., Elenga, R.G., Ahouet, L., Bouyila, S. and Konda, S. (2019) Modeling the Drying Kinetics of Earth Bricks Stabilized with Cassava Flour Gel and Amylopectin. Geomaterials, 9, 40-53. https://doi.org/10.4236/gm.2019.91004