Earth blocks stabilized by cow-dung

WOS:000379589500010International audienceIn developing countries, most of the population cannot afford conventional building blocks made with the sand-cement mixture. In addition, these blocks do not provide thermal comfort and have a high embodied energy compared to vernacular materials. The main objective of this work was to produce low cost, resistant and durable (good resistance to water) blocks with a thermal behaviour enabling quality comfort indoor. For that purpose, the effects of cow-dung on microstructural changes in earth blocks (adobes) are investigated by means of X-ray diffraction, thermal gravimetric analyses, scanning electronic microscopy coupled with energy dispersive spectrometry, and video microscopy. The effects of these changes on the physical properties (water absorption and linear shrinkage) and mechanical properties (flexural and compressive strengths) of adobe blocks are evaluated. It is shown that cow-dung reacts with kaolinite and fine quartz to produce insoluble silicate amine, which glues the isolated soil particles together. Moreover, the significant presence of fibres in cow-dung prevents the propagation of cracks in the adobes and thus reinforces the material. The above phenomena make the adobe microstructure homogeneous with an apparent reduction of the porosity. The major effect of cow-dung additions is a significant improvement in the water resistance of adobe, which leads to the conclusion that adobes stabilized by cow-dung are suitable as building materials in wet climates

Measurement of mechanical and physical properties of particleboard by hybridization of kenaf with rubberwood particles

Kenaf is one of the potential raw materials available in Malaysia to use for particleboard manufacturing as an alternative solution to balance shortage of rubberwood (RW) supply. In this study, particleboard manufactured from kenaf stem (KS) and RW particle blends at different RW loading (0%, 50%, 70%, 100%) and resin levels (6%, 8%, 10%). Urea formaldehyde resin is used as a binder. The effects of RW:KS ratio and resin content on mechanical and dimensional stability properties of hybrid particleboard were determined. The results indicated that particleboards bonded with 10% resin level and 50:50 (RW:KS) had the highest strength (19.08 MPa) while particleboards made of 70:30 (RW:KS) display better stiffness (2.23 GPa). Statistical analysis using ANOVA and LSD were conducted on the obtained results. The results show that RW:KS ratio has greater influence over thickness swelling (TS) and water absorption (WA) of particleboard than the level of resin content. The relationship between internal bonding (IB) and TS of particleboards were also examined and obtained strong inverse relationship between IB and TS. Hybrid particleboards made from 70% RW and 30% KS with 10% resin content display over all good properties and comparable with 100% RW (control) samples. It concluded that kenaf stem can replace rubberwood particles up to 50% but the resin level must be kept at 10% or more because lower resin level (⩽8%) significantly decrease strength of the particleboard

Influence of chemical treatment on the tensile properties of kenaf fiber reinforced thermoplastic polyurethane composite

In this study, the effect of polymeric Methylene Diphenyl Diisocyanate (pMDI) chemical treatment on kenaf (Hibiscus cannabinus) reinforced thermoplastic polyurethane (TPU/KF) was examined using two different procedures. The first consisted of treating the fibers with 4% pMDI, and the second involved 2% NaOH + 4% pMDI. The composites were characterized according to their tensile properties, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The treatment of the composite with 4% pMDI did not significantly affect its tensile properties, but the treatment with 2% NaOH + 4% pMDI significantly increased the tensile properties of the composite (i.e., 30 and 42% increases in the tensile strength and modulus, respectively). FTIR also showed that treatment with 2% NaOH + 4% pMDI led to the strongest H-bonding. Additionally, the surface morphology of specimens after tensile fracture confirmed that the composite treated with 2% NaOH + 4% pMDI had the best adhesion and wettability

Effect of Alkali and Silane Treatments on Mechanical and Interfacial Bonding Strength of Sugar Palm Fibers with Thermoplastic Polyurethane

Sugar palm fibers (SPF) are one of valuable natural fibers which are abundantly available in Malaysia as agricultural biomass. The aim of this study to investigate on the effects of alkali, silane, and combination between alkali (6%) and silane (2%) on physical and mechanical properties of SPF to improve interfacial bonding of SPF with thermoplastic polyurethane (TPU) matrices. Scanning electron microscopy and Fourier transform infrared spectroscopy was used to observe the effectiveness of the alkali and saline treatments in the removal of impurities. Silane treated SPF exhibits better tensile strength than those of alkali, alkali-silane treated and untreated SPF. Droplet test indicates that the interfacial stress strength (IFSS) of alkali and silane treated SPF are enhanced whereas silane treated fibers exhibit highest IFSS. It is assumed that fiber treatments will help to develop high performance SPF reinforced polymer composites for industrial applications

A study into the characteristics of gomuti (Arenga pinnata) fibre for usage as natural fibre composites

Gomuti is a natural fibre obtained from Arenga pinnata tree. In its native countries, the fibre has been used as roof, rope, insulation and water filter. This paper presents a study into the physical, mechanical and thermal characteristics of gomuti fibre to observe its viability as natural fibre composite material. The study includes observations of fibre morphology, diameter, density, single fibre tensile testing and observation of fibre thermal stability. It was found that diameter of the studied gomuti fibre was in a range of 81–313 mm, with an average of 168 mm. Density of gomuti was �1.40 g/cm3. The average strength of single gomuti fibre was 173.9 MPa and the average modulus of elasticity was 3847 MPa. Alkali treatment with sodium hydroxide was conducted to evaluate modifications in the fibre's characteristics. The treated gomuti fibres show altered diameter range, density, single fibre tensile properties and different thermogravimetric plots. Based on the results, gomuti fibre can be considered viable to be developed into natural fibre composites