Evaluating the effects of agricultural wastes on concrete and composite mechanical properties: a review

Wastes generation and emission of greenhouse gases are the major concerns of the contemporary world. Concrete’s cements companies in the globe are producing up to 2.8 billion tons of cements annually. This contributed to the emission of anthropogenic substances into the atmosphere which destroys the ozone layers. The incessant disposal of these agricultural wastes has detrimental effect on the environmental and human health. Thus, utilizing these wastes as secondary resources in concrete is a reasonable consideration in sustainable waste management in the circular economy. The use of agricultural wastes in concrete production has been gaining attraction in recent years, however, their effectiveness and performance in concrete need evaluation. This study presents an overview of the effects of some agricultural wastes: Bagasse, Coconut shell, Cotton, Oil palm and Hemp fibers on concrete and composite’s mechanical properties. As reviewed, Sugar-Cane Bagasse Ash (SCBA) and Coconut Shell Ash (CSA) are rich in cementitious (pozzolanic) properties (SiO2, Fe2O3 and Al2O3) for cement production up to 70%. Sugar-cane bagasse and oil palm-fiber ashes improved concrete workability. SCBA and CSA highly increased the concrete compressive strengths. The concrete tensile strengths were increased up to 97% with the inclusion of cotton and bagasse ashes. The SCBA, hemp-fiber and treated oil palm - fiber ash increased the concrete and composite’s flexural strengths up to 11.3%, 26.2% and 50.7% respectively. In conclusion, the output of this review will supply full data of the research gaps yet to cover on the use of agro-wastes in concrete for future investigations

Microstructure Transformation In Palm-Fiber Cell Wall And Its Influence On the Fiber's Mechanical Properties During Alkali Treatment

In this study, we examined the microstructure transformation of palm fiber and the influence of this transformation on the fiber mechanical properties during alkali treatment. The fibers were treated with different concentrations of NaOH to study the change rules of the microstructure and the tensile properties. FT-IR microspectroscopic imaging and confocal laser scanning microscopy were adopted to observe microstructure transformation during alkali treatment. Research results showed that the hemicellulose and lignin in the fiber cell wall were removed by alkali treatment, leading to a rearrangement of cellulose chains. The tensile properties palm fibers were significantly improved because of crystallinity alterations in the cell walls after alkali treatment. This study might provide a basis for palm fiber’s high-value utilization in the field of materials.

PENGARUH PENAMBAHAN SERAT IJUK PADA PAVING BLOCK BERBAHAN PLASTIK HDPE

The waste problem continues to be a complex issue. On the one hand, the use of plastic still cannot be abandoned by humans, but on the other hand the waste produced is very difficult to decompose. In Indonesia, in 2015 the amount of waste reached 64 million tons / year. Palm fiber is one of the materials that can be used as composite fiber. In this study, a research will be conducted on the manufacture of paving blocks made from HDPE plastic combined with variations of 0%, 1%, 2% and 3% palm fiber. Plastic waste is melted and put into a mold and then combined with palm fiber. From the test results, the highest compressive strength (2% fiber variation) was 45.91 kg/cm2 and the average compressive strength was 45.28 kg/cm2. This compressive strength is under the minimum compressive strength standard of SNI Permasalahan sampah masih terus menjadi isu kompleks. Di satu sisi, penggunaan plastik masih belum bisa ditinggalkan manusia, namun di sisi lain sampah yang dihasilkan sangat sulit terurai. Di indonesia, pada tahun 2015 tercatat banyaknya sampah mencapai 64 juta ton/tahun. Ijuk merupakan salah satu material yang dapat digunakan sebagai serat komposit. Pda penelitian ini akan dilakukan penelitian mengenai pembuatan paving block berbahan dasar plastik HDPE yang dikombinasikan dengan variasi serat ijuk 0%, 1%, 2 % dan 3%. Limbah plastik dilelehkan dan dimasukkan ke dalam cetakan lalu dipadukan dengan serat ijuk. Dari hasil pengujian, didapatkan kuat tekan tertinggi (variasi serat 2%) sebesar 45,91 kg/cm2 dan kuat tekan rata-ratanya sebesar 45,28 kg/cm2. Kuat tekan ini berada di bawah standar kuat tekan minimal dari SNI.

Enhanced Optimization of Bioethanol Production from Palm Waste Using the Taguchi Method

In the present study, palm fiber (PF) and palm fronds (PFN) were selected as local agricultural wastes for the extraction of different biopolymers (cellulose, hemicelluloses, and lignin) by alkaline sodium hydroxide (PF, 2.37% NaOH at 86.5 °C for 1.6 h; PFN, 6% NaOH at 90 °C for 1 h) and bioethanol production. The processes of extraction were optimized by the experimental design method of Taguchi. The total carbohydrates of PF and PFN obtained were 24.4% and 31.0%, respectively. In addition, the untreated palm fiber (UPF), untreated palm frond (UPFN), cellulose palm fibers (CPF), and cellulose palm fronds (CPFN) were subjected to enzymatic hydrolysis processes using crude enzymes and commercial enzymes at 48 °C and pH 5.5. The results indicate that the maximum reducing sugars used were CPF 229.90, CPFN 243.69, UPF 120.19, and UPFN 100.00 (mg/g), which were obtained at a crude enzyme loading. CPF and CPFN hydrolysates were then successfully converted into bioethanol by a separate enzymatic hydrolysis and fermentation by Saccharomyces cerevisiae. Anaerobic cultivation of the hydrolysates with S.cerevisiae resulted in 0.222 g/g and 0.213 g/g bioethanol in the case of CPF and CPFN, respectively. Optimization processes could be an innovative approach to the sustainable development of bioethanol production.