Strength Evaluations for Treated peat with Cement and Polypropylene Fibres using CBR Tests
Peat or organic soils are those types of soils that contain a significant amount of organic material derived from plants or animals. Although peat deposits create obvious topographic features such as swamp and bogs, others are buried underground, having been covered with inorganic alluvial soils. These often are difficult to detect and are the source of differential settlements when subjected to loads from civil engineering projects. This article describes a laboratory study on treating peat using ordinary Portland cement (OPC) as binding agent and polypropylene fibers as additive. Due to high initial water content of peat, the usual moist curing technique used to cure the treated peat samples is not used and air curing method is used instead. Beside routine laboratory tests on plain peat, strength evaluation test on the treated peat samples with cement and fibres used in the research was California bearing ratio (CBR). Air curing period used was 90 days for the CBR (soaked and un-soaked) test samples. Various amounts of cements ( 15, 30 and 50%) as well as 0.15% of fibres were used to treat plain peat samples. The result of CBR tests show significant strength improvement of stabilized peat through curing period. Also as the cement amounts increase, treated samples gain more strength, while polypropylene fibers when added to the treated peat with cement not only give more strength values, rather contribute a considerable amount of uniformity and intactness to the cement treated peat
Precast stabilized peat columns to reinforce peat soil deposits.
This article describes laboratory research on precast columns made of peat soil and ordinary Portland cement, with and without polypropylene fibers. The columns used in this study unlike the usual in situ or in place columns used previously, that are formed inside prepared holes in the ground, are formed outside the hole, and then inserted into the ground holes. The process of making precast stabilized peat columns includes mixing peat soil with a specified amount of cement, (with or without polypropylene fibers) at their optimum moisture (found from compaction tests) contents. The mixture is then compacted into molds and left to dry. As the stabilized columns dry out, they gain strength. When drying is complete, they are taken out of their molds and inserted in the pre-drilled holes. In this laboratory study, long precast columns (L/D > 4) were used to reinforce undisturbed peat soil samples. The strength evaluation for the precast stabilized columns was done through consolidated undrained triaxial tests. The undisturbed peat soil in the study has been used as control sample. The results of the study obtained from shear strength parameters, stress-strain curves and undrained modulus prove that precast stabilized peat columns can be used to reinforce and strengthen weak deposits of peat soil. Their production requires relatively small amounts of cement compared with the usual in situ columns but provides higher strength values, and therefore provides more load-bearing capacity. Since the production process does not waste much of the materials involved and does not use any fill materials the columns can also be considered environmentally friendly.
Single step formation of biocompatible bimetallic alloy nanoparticles of gold and silver using isonicotinylhydrazide.
Manufacturing nanoparticles with controlled physicochemical properties using environment-friendly routes have potential to open new prospects for a variety of applications. Accordingly, several approaches have been established for manufacturing metal nanoparticles. Many of these approaches entail the use of hazardous chemicals and could be toxic to the environment, and cannot be used readily for biomedical applications. In the present work, we report a single step bio-friendly approach to formulate gold (Au), silver (Ag), and Au-Ag alloy nanoparticles with desired surface corona and composition using isonicotinylhydrazide (INH) as a reducing agent. INH also functioned as a stabilizing agent by enabling a surface corona around the nanoparticles. Remarkably, within a single step INH could also provide a handle in regulating the composition of Au and Ag in bimetallic systems without any additional chemical modification. The physicochemical and surface properties of the different nanoparticles thus obtained have been examined by analytical, spectroscopic and microscopic techniques. Cell cytotoxicity (release of lactate dehydrogenase), cell viability and intracellular reactive oxygen species (ROS) assays confirmed that the Au, Ag, and Au-Ag bimetallic nanoparticles prepared with INH are biocompatible. Finally, the presence of organic surface corona of INH on the nanoparticles was found to impart nanozyme activity and antimycobacterial sensitivity to the nanoparticles.