Freeze-Thaw Behavior of Stabilized Clayey Soil with Red Mud and Cement

The clayey soils in areas with seasonal frost are exposed to at least one freeze-thaw cycle every year and worsen their engineering properties. To prevent the engineering properties of clayey soils, it is necessary to improve the freeze-thaw resistance of them. In this study, the clayey soil was stabilized by using red mud and cement additive materials. Prepared samples of clayey soil and stabilized clayey soil were subjected to the unconfined compressive test. To investigate the effects of red mud and cement additive materials on the freeze-thaw resistance of clayey soil, the natural and stabilized expansive soil samples were exposed to the freeze-thaw cycles under laboratory conditions. The obtained results showed that the red mud and cement additive materials increased the freeze-thaw resistance of clayey soil. Consequently, it was concluded that red mud and cement additive materials can be successfully used to improve the freeze-thaw resistance of clayey soils.

Effects of Quartzite on the Desiccation Cracks of Clayey Soils Exposed to Wetting-Drying Cycles

The compacted clayey soils crack on drying because of their high swelling potential, and their hydraulic conductivities increase. To solve this problem, it is essential to stabilize the clayey soils using additive materials. The aim of this study is to examine the suitability of quartzite as a stabilization material to reduce the development of desiccation cracks in compacted clayey liner and cover systems. Experimental study was conducted to investigate the effect of wetting-drying cycles on the initiation and evolution of cracks in compacted clayey soils. For experimental studies, seven samples were prepared stabilized by using 0%, 2.5%, 5%, 7,5%, 10%, 12,5% and 15% quartzite and then they were subjected to four subsequent wetting-drying cycles. The results show that quartzite decreases the development of desiccation cracks on the surface of compacted samples. It is concluded that quartzite as a geological material can be successfully used to reduce the development of desiccation cracks in compacted clayey liner and cover systems exposed wetting-drying cycles.

Analisis Ionic Soil Stabilizer (Iss 2500) Terhadap Nilai Durabilitas Tanah Lempung Plastisitas Rendah Pada Perkerasan Jalan

Various methods of soil stabilizations in Indonesia are more increasingly used for soil quality improvement, one of the methods is using chemically additive materials with ISS 2500 (Ionic Soil Stabilizer). This chemical solution is able to cover soil particles through electro-chemical reactions, so that the water content is separated and cohesion among soil particles is strengthened. However, unstable weather and temperature changes (durability) in forms of rainfall and heat influence and cause soil defects especially in road construction. In this reseach, the tested soil was clay with low plasticity from Karang Anyar region in Lampung Selatan regency, and mixed with 0.9 ml of ISS 2500 solution content the ISS optimum content. To enable reactions between soil and ISS 2500, the mixed soil was treated in 18 days with durability treatment and cycles addition; 0,2,4, and 6 cycles. The laboratory results indicated that CBR test in cycle 0, 2, 4, and 6 obtained 8%, 7.6%, 5.7%, and 5.1% respectively. The CBR value of the mix decreased regularly along with given amounts of additional cycles. However, the overall CBR value of the stabilization of low plasticity clay with an ISS of 2500 (Ionic Soil Stabilizer) can meet the requirements of Bina Marga as subgrade, because the CBR value obtained is greater than 5% even though it is given cycle treatment. The ISS 2500 material can be used as an alternative stabilization material for the improvement of the subgrade.

Simultaneous synthesis of graphite-like and amorphous carbon materials via solution plasma and their evaluation as additive materials for cathode in Li–O2 battery

Cathode materials are essential for enhancing electrocatalytic activity in energy-conversion devices. Carbon is one of the most suitable cathodic materials for Li–O2 batteries owing to its chemical and thermal stability. Carbon materials synthesized from tributyl borate (TBB) using a nonthermal solution plasma method were characterized using x‐ray diffraction, Raman, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, and x-ray photoelectron spectroscopy and were evaluated as additive materials for cathodes in a Li–O2 battery. Two separate carbon materials were formed at the same time, a carbon dispersed in solution and a carbon precipitate at the bottom of the reactor, which had amorphous and graphite-like structures, respectively. The amorphous carbon contained boron and tungsten carbide, and the graphite-like carbon had more defects and electronic conductivity. The crystallinity and density of defects in the graphite-like carbon could be tuned by changing the SP operating frequency. The Li–O2 battery with the amorphous carbon containing boron and tungsten carbide was found to have a high capacity, while the one with the graphite-like carbon showed an affinity for the formation of Li2O2, which is the desired discharge product, and exhibited high cycling performance.

An analytical study on the relationship between the fungal degradation and multi-component nature of paper manuscripts

Purpose This paper aims to identify the most common fungal species that grow on paper manuscripts and cause bio-deterioration. It also detects the impact of additive materials on fungal degrading and builds a wide database. Thus, it helps conservators understand this phenomenon. Design/methodology/approach In total, 15 samples were collected from different paper manuscripts suffering from fungi. The achievement of the study objectives depends on using a variety of analyzes, such as a microbiological study, which indicated that three main fungi grew on the paper samples. Then, a digital microscope and an environmental scanning electron microscope were used to detect the effect of fungi on paper fibers. Fourier transform infrared microscopy was used to identify the binding medium and the X-ray diffraction method was used to measure the crystallinity index of cellulose of the paper samples. Findings Arabic gum was used as a binder medium with the samples. Aspergillus Niger, Aspergillus Fumigatus and Aspergillus Clavatus were the most common fungal species that grew on the Qur’an papers under investigation. They also caused much common damage to the paper samples. The results of the analyzes also showed that the highest crystallinity index of cellulose was in the samples that contained the lowest rate of fungal growth. Originality/value This paper highlights the relationship between fungal degradation and the multi-component nature of paper manuscripts. It builds a wide database that correlates the composition and the degradation of the Qur’an papers.