Modelling the Effects of Nanomaterial Addition on the Permeability of the Compacted Clay Soil Using Machine Learning-Based Flow Resistance Analysis

Impermeable base layers that are made of materials with low permeability, such as clay soil, are necessary to prevent leachate in landfills from harming the environment. However, over time, the permeability of the clay soil changes. Therefore, to reduce and minimize the risk, the permeability-related characteristics of the base layers must be improved. Thus, this study aims to serve this purpose by experimentally investigating the effects of nanomaterial addition (aluminum oxide, iron oxide) into kaolin samples. The obtained samples are prepared by applying standard compaction, and the permeability of the soil sample is experimentally investigated by passing leachate from the reactors, in which these samples are placed. Therefore, Flow Resistance (FR) analysis is conducted and the obtained results show that the Al additives are more successful than the Fe additive in reducing leachate permeability. Besides, the concentration values of some polluting parameters (Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), and Total Phosphorus (TP)) at the inlet and outlet of the reactors are analyzed. Three different models (Artificial Neural Networks (ANN), Multiple Linear Regression (MLR), Support Vector Machine (SVM)) are applied to the data obtained from the experimental study. The results have shown that polluting parameters produce high FR regression similarity rates (>75%), TKN, TP, and COD features are highly correlated with the FR value (>60%) and the most successful method is found to be the SVM model.

The Implementation of Industrial Byproduct in Malaysian Peat Improvement: A Sustainable Soil Stabilization Approach

Peat is a well-known problematic soil associated with poor engineering properties. Its replacement with an expensive competent foundation material is practiced for road embankment construction which is costly and causes greenhouse gas emissions. Therefore, this paper investigated the effectiveness of a byproduct from a metal industry (silica fume) to stabilize peat along with ordinary Portland cement (OPC) through a series of experimental tests. After peat-indexed characterization, a number of standard compaction and mechanical tests were performed on the stabilized and parent peat. For this purpose, nine designated mixes were prepared possessing various combinations of silica fume (SF) and 10–20% OPC. Unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests were carried out after 7, 14, and 28 days of curing to assess strength enhancement and binder effectiveness, and the microstructural evolution induced by the binders was examined with scanning electron microscopy (SEM). The analysis revealed a substantial improvement in mechanical properties with the incorporation of SF and OPC, ultimately meeting the minimum strength requirement for highway construction (i.e., 345 kPa). A peak UCS of 1063.94 kPa was recorded at 20% SF, and an unsoaked CBR value of 42.95 was observed using 15% SF and 15% OPC after 28 days of curing. Furthermore, the increasing percentage of hydraulic binders exhibited brittle, collapsible failure, while the microstructural study revealed the formation of a dense matrix with a refined pore structure in the treated peat. Finally, a significant statistical analysis was carried out by correlating the test parameters. In this way, rather than stockpiling and dumping, an industrial byproduct was implemented in peat stabilization in an eco-friendly manner.

Comparison of fly ash with Lapindo mud as a land stabilizer for landfill in Pasuruan–Indonesia

The paper discusses the comparison of fly ash with Lapindo mud as a land stabilizer for a landfill in Pasuruan, Indonesia. Land for landfills has a low level of stability due to the condition of garbage that has accumulated and undergoes a process of decay. This land condition is less favorable to support the construction of the building above it if one day the location is used for construction. Therefore, it is necessary to stabilize the soil first. The purpose of this study was to determine the effect of adding a mixture of TPA soil with fly ash and Lapindo mud. The method used by sieve testing and compaction of the specimens for each treatment consisted of a mixture of TPA soil with fly ash and TPA soil with Lapindo mud, while the percentages of fly ash and Lapindo mud to the dry weight of the original soil were respectively 0 %, 10 %, 15 %, and 20 %. The results showed that stabilization of the landfill with fly ash reduced the silt content while stabilization with Lapindo mud increased the levels of silt in the landfill so that fly ash was better than Lapindo mud for stabilization of the landfill. The specific gravity values for both stabilization mixtures increased equally. Based on the results of the standard compaction test for the addition of a mixture of fly ash, the OMC value decreases and the greater the value of dmaxs indicates that fly ash is good for landfill stabilization, while the addition of a mixture of Lapindo mud increases the OMC the smaller the value of dmaxs. For the direct shear test of the two mixed soils, the value of the internal friction angle (Æ) increased. The percentage value of the optimum mixture of mixed soil+fly ash is 14 % with an internal shear angle (Æ) of 38°, while the stabilization of landfill with Lapindo mud obtained the optimum mixture percentage value of 11 % with an internal shear angle (Æ) of 31°

Pengaruh Penambahan Serat Rami pada Tanah Terjun-Medan dengan Pengujian Standard Compaction, Triaxial Unconsolidated Undrained, dan Prediksi Balik dengan Plaxis 2D

Tanah mempunyai peranan yang penting dalam konstruksi. Daya dukung tanah wajib mampu menahan beban struktur di atasnya. Problematika tanah lunak yang sering dijumpai seperti kerusakan jalan perkerasan lentur maupun kaku, kelongsoran timbunan, kelongsoran lereng, dan penurunan tanah yang menyebabkan kerusakan struktur. Diperlukan inovasi yang ramah lingkungan dalam penanganan tanah lunak tersebut secara in-situ disamping dengan pertimbangan dari segi ekonomis, waktu, dan ketersediaan material. Penelitian bertujuan untuk mengetahui pengaruh penambahan serat rami pada tanah terhadap kekuatan geser dan kepadatan kering maksimum tanah. Penelitian ini menggunakan serat rami yang dicampurkan secara acak dengan tanah dengan kadar rami sebesar 1%, 2%, 3%, 4% dan 5% dari berat tanah kemudian dilakukan compaction test dan Triaxial UU. Pengujian Triaxial UU dilakukan untuk tanah dengan kandungan serat maksimum. Hasil penelitian ini yaitu kepadatan kering maksimum (ℽdmax) tanah mengalami penurunan seiring dengan penambahan serat rami dimana ℽdmax tertinggi sebesar 1,595 g/cm3 sedangkan ℽdmax terendah sebesar 1,438 g/cm3. Penambahan serat rami sebesar 5% menghasilkan peningkatan pada nilai kekuatan geser (cu) hasil pengujian Triaxial UU sebesar 477,1% dari 1,05 kg/cm2 menjadi 5,01 kg/cm2. Hasil pemodelan Triaxial UU dengan pemodelan harderning soil model pada program Plaxis 2D cukup mendekati dengan hasil pengujian laboratorim dengan hasil tegangan deviatorik yang relatif sama.

Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

In this study, a self-sensing cementitious stabilized sand (CSS) was developed by the incorporation of hybrid carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) based on the piezoresistivity principle. For this purpose, different concentrations of CNTs and GNPs (1:1) were dispersed into the CSS, and specimens were fabricated using the standard compaction method with optimum moisture. The mechanical and microstructural, durability, and piezoresistivity performances, of CSS were investigated by various tests after 28 days of hydration. The results showed that the incorporation of 0.1%, 0.17%, and 0.24% CNT/GNP into the stabilized sand with 10% cement caused an increase in UCS of about 65%, 31%, and 14%, respectively, compared to plain CSS. An excessive increase in the CNM concentration beyond 0.24% to 0.34% reduced the UCS by around 13%. The addition of 0.1% CNMs as the optimum concentration increased the maximum dry density of the CSS as well as leading to optimum moisture reduction. Reinforcing CSS with the optimum concentration of CNT/GNP improved the hydration rate and durability of the specimens against severe climatic cycles, including freeze–thaw and wetting–drying. The addition of 0.1%, 0.17%, 0.24%, and 0.34% CNMs into the CSS resulted in gauge factors of about 123, 139, 151, and 173, respectively. However, the Raman and X-ray analysis showed the negative impacts of harsh climatic cycles on the electrical properties of the CNT/GNP and sensitivity of nano intruded CSS.

IT IS NECESSARY TO UNDERSTAND THE VALUE OF K DENSITY WHEN TESTING THE QUALITY OF NATURAL AGGREGATE LAYER IN ROAD COAT STRUCTURE IN THE SOUTH

Density is an important parameter reflects the quality of the foundation and base construction. Therefore, the exact determination of density parameters is extremely necessary in the work of checking and accepting the work items. The paper presents the results of the research to determine the density of the natural mix layer in the road coat structure with flexible and rational adjustment of the oversized grain content - during standard compaction as well as sampling for field test of density to overcome difficulties and obstacles when implementing the inspection of road structure.

Using Natural Pozzolan, Cement and Lime for Stabilizing Soil in Earth Dams

The paper has focused on studying the ability of using natural pozzolan to combine lime and cement in process of stabilized soil, implementing experimental contents for on-site soil including: grain composition, plastic limit, plasticity index, mineral parts and other common mechanical properties, standard compaction. Followed by experiments for soil, cement and pozzolan stabilized soil mixtures, including standard compaction, compressive strength. A suitable model of physical experiments to simulate and prove lime, cement and pozzolan stabilized soil meets the criteria for making waterproofing materials for earth dams in the Central Highlands

A novel device for inclined compaction test on soils

It can be said that the soil compaction test is currently the standard method for obtaining the right amount of water to be added in order to achieve a maximum dry density. Then, the water content obtained from laboratory work, known as optimum moisture content, is utilised in the field for compacting the soil. It should be noted that the compaction test is carried out on a soil sample prepared in a mould horizontally laid. In the field, however, quite often the compaction is done on side embankments or sloping grounds. Hence, using the laboratory result to control the field density for such cases is problematic. Therefore, this study developed a device that could be used to conduct the compaction test concerning the following conditions: (1) compaction is vertically applied to a soil sample inclined at various angles (VC), and (2) compaction is normal to an inclined soil sample (IC). Some initial tests on lateritic soil using both methods developed showed that at the same energy applied the densities are quite different. These results confirm that, in the case of sloping ground, the standard compaction test may not be appropriate.

Toward a better understanding of the effects of cement treatment on microstructural and hydraulic properties of compacted soils

This study deals with the problem of the experimental characterization of cement-treated compacted soils in terms of microstructural and hydraulic properties. Some tests are conducted on two different types of soil: silty sand and clay as fine soils and gravelous sand and alterite as granular soil. Some samples are mixed with 5% of cement and compacted at different levels (i.e., 85%, 95%, 100% and 105% of the maximum dry density, respectively, as achieved using the standard compaction method). The results of the mercury intrusion porosimetry (MIP) tests performed on these cement-treated soils reveal significant changes as regards macropores due to the combined effects of treatment and compaction. Consequently, a decrease in the permeability is clearly observed for all the tested soils when the degree of compaction increases. This decrease is significantly greater in fine soils, which are more sensitive to compaction effects than granular soils.

ANALISIS ENERGI PEMADATAN TANAH DI LABORATORIUM

The density test for soil in the laboratory can be a mild density test (standard proctor) and a modified density test (modification proctor). Both types of compaction provide different levels of density. This paper aims to analyze the energy produced by both types of compaction. The results show that the compaction modification energy is greater than the standard compaction energy. These results are influenced by the number of layers and the difference of the mass of the pounder on both types of compactionKey words: compaction energy, standard proctor, modified proctor