Thermo-Mechanical Properties Study of Stabilized Soil Bricks to Sugar Cane Molasses and Cassava Starch Binders

The current study deals Swith thermo-mechanical properties of stabilized soil small bricks with the help of organic binders of sugar cane molasses and cassava starch. Different formulations of soil concrete have been suggested after the geotechnical characterization of samples of soil was taken. From these, it arises that the studied soil is the most plastically clay (of type A3) according to GTR classification. Samples made of small bricks and measured out at 4%, 6% and 8% of binders (molasses, starch or molasses + starch) have been warmed up to different temperatures (100°C, 150°C, 200°C and 250°C) for the rising of the thermic behavior under different conditions and submitted to crushing testings for the estimation of characteristic resistances to the compression. According to the mechanical behavior, we note an improvement of resistances for small bricks measured 4%, 6% and 8%, of molasses respectively of 32.44%, 32.06% and 23.43% against the value of reference for small bricks without molasses. In the same way, the binder (molasses + starch) also reveals an improvement of resistance to the compression of 13.27%, 26.17% and 26.17%. On the contrary, the stabilization with the starch binder did not bring a significative improvement. According to the thermic influence, the heating at 100°C of stabilized small bricks at 4%, 6% and 8% of molasses, reveals a significative improvement of resistances. Moreover, the stabilization with the starch reveals on the contrary a good behavior for heatings at 150°C and 250°C. In short, for the binder (molasses + starch), it is the heating at 200°C that shows some improvements of remarkable resistances. Different analyses of realized statistics also show the effectivity of obtained results. For all realized formulations, the measuring out at 6% of binders (molasses, or molasses + starch) seems as optimal in front of the best thermo-mechanical revealed properties.

Effect of Incorporation of Chips and Wood Dust Mahogany on Mechanical and Acoustic Behavior of Brick Clay

An experimental study was carried out on bricks using local materials in order to take into account the waste wood management to protect the environment and to reduce the cost of the habitat. Chips and sawdust were built-in clay bricks in order to study their influence on the compressive strength, Young’s modulus and the speed for soundproofing. Testings in compressive strength were made on the parallelepiped clay bricks, stabilized with different percentages of cement, with incorporation to various percentages of sawdust or wood chips (Mahogany), using a universal press. Young’s modulus was measured from the speed of sound by the ultrasonic method. The results obtained show that the incorporation of mahogany tree chips in the stabilized brick at 8% of cement, does not have much effect on the compressive strength. It was found that the incorporation of chips or sawdust on the clay brick, does not improve the compressive strength. The Young’s modulus decreases with increasing content of sawdust and practically remains constant regardless of the content of chips at 4% and 6% of cement. The clay brick mixed with 8% of mahogany sawdust can be an acoustic barrier.

Impact of pH Water and Mineralogical Microstructure of Soil Mixed with Wood Waste on the Compressive Strength of Composite Bricks;and Bricks Resistance Modeling

This study includes the manufacture of cement stabilized clay bricks with embedded mahogany chips. The impact of this waste and its interaction with water in the bricks was evaluated on the mechanical properties. The compressive strength tests using a universal press were carried out on bricks with and without adding wood chips. The results obtained show that the incorporation of wood chips into the bricks decreases the compressive strength. This reduction in compressive strength led us to conduct an analysis of clay and water as intrinsic factors, before and after incorporation of untreated wood waste. Thus, a mineralogical analysis of the clay with and without mahogany chips was made using an X-ray diffractometer, using an anticathode of cobalt with the line Κα, of wavelength λ = 1789&#197. After quantification of the mineral constituents, it is noted that the concentration of SiO2 decreases considerably in the clay with addition of wood chips, resulting in the reduction of the compressive strength in these composite materials (from Rc = 9.26 MPa at 0% of chips to 3.55 MPa at 8%). A mathematical model following the interpolations of Lagrange was then proposed. The analysis of the water resulting from the impregnation of dry wood chips in the water, shows that the water becomes strongly acid (pH = 4.3 at the 7th day of immersion), thus contributing to the reduction of resistance. This analysis of intrinsic factors will allow future studies to take into account the treatment of wood waste by different processes in order to increase the mechanical, thermal and acoustic properties of composite bricks with the same contents, thus generating massive support for the use of its composite materials.

Effect of Wood Waste on Acoustic and Magnetic Properties of Composite Bricks and Correlation between Sound Velocity and Magnetic Induction in These Bricks

In the present study, kambala (botanical name: Chlorophora excelsa and Chlorophora regia) wood wastes were incorporated into stabilized earth bricks in order to test their acoustic insulation capacity of the walls;leading to better waste management from the timber industry. Two methods have been applied to determine the influence of the wood waste content in the stabilized earth bricks, on the weakening of the level of noise reception coming from the environmental medium, in an apartment built with composite bricks (earth + wood chips + cement). This influence has also been analyzed on the magnetic field induced by these bricks. The results showed that the level of sound reception through these bricks decreases with increasing wood waste content regardless of the method used (from 110 dB to 68 dB, respectively for Φb = 0% and Φb = 8%). The kambala wood waste in cement-stabilized clay bricks induces a magnetic field that increases with the wood waste content;the high contents of the wood chips causing an increase in the magnetic permeability of the composite medium. The correlation between the noise level and the magnetic field of the bricks shows that the noise level declines with increasing magnetic induction of the bricks.

Influence of Aggregate Grain Size on the Formulation of Sand Concrete in the Construction Industry in Congo

The main objective of this study is to contribute to the optimization of the formulation of sand concretes and its valorisation according to natural sands from different quarries or extraction sites. Physical characteristics of natural sands have been determined and improved by the addition of crushing sand, taking into account the too fine elements of the sand. Four types of sand were used (Congo River, Djiri, Mfilou, crushed sand). The concrete formulations proposed from improved sands (30% crushed sand and 70% natural sand) reveal an increase in mechanical strength. Thus, it appeared that this improvement of the natural fine sands by the crushing sand has brought a clear increase in the maneuverability of the concretes and the physico-mechanical characteristics of nearly 50%, although this crushing sand has a sand equivalent value of less than 70%. These results augur well for the durability of structures in the construction industry in Congo.