Compacted laterite and bentonite, as well as a mixture of the two, are strongly impermeable and can effectively prevent the migration and diffusion of contaminants. This study explored the feasibility of employing a laterite/bentonite mixture as a vertical barrier in landfills, tailings ponds, or sites contaminated by heavy metals. Permeability tests using chemical solutions of different concentrations and compression tests were performed on mixed bentonite/laterite samples with different dry densities and mixing ratios. The permeability and consolidation characteristics were verified using scanning electron microscopy. The hydraulic conductivity of the laterite samples decreased with increased dry density, and the hydraulic conductivity of the mixed-soil samples decreased with increased bentonite content. Adding bentonite significantly improved seepage control performance. The hydraulic conductivity of the pure laterite was 4.7 × 10−7 cm/s, whereas that of the laterite sample mixed with 20% bentonite was 1.6 × 10−8 cm/s. The compacted laterite with a dry density of 1.5 g/cm3 was demonstrated to satisfy the permeability specifications to serve as a landfill seepage control system. When the concentration of the heavy metal or salt solutions increased, the laterite flocculation increased, and the hydraulic conductivity decreased. The laterite in the mixed soil samples substantially affected these characteristics, particularly decreasing the hydraulic conductivity. As the concentration of the chemical solutions increased, the yield stress of the compacted samples and the compression index decreased, and the compression performance improved. These findings indicate that chemical solutions significantly affect the hydromechanical behavior of a laterite/bentonite mixture used as an engineered barrier.

Effects of chemical solutions on the hydromechanical behavior of a laterite/bentonite mixture used as an engineered barrier

Assessment of the influence of copper and zinc on the microstructural parameters and hydraulic conductivity of bentonites on the basis of SEM tests.

Study on the microscale structure and anti-seepage properties of plastic concrete for cut-off walls modified with silica fume: Experiment and modelling

The effects of potentially toxic metals (copper and zinc) on selected physical and physico-chemical properties of bentonites.

Insight into barrier mechanism of fly ash-bentonite blocking wall for lead pollution in groundwater

Studies on the chemical compatibility of soil-bentonite cut-off walls for landfills.

Epoxy resin insulation paint was prepared with epoxy resin (E44) as binder and with proper inorganic fillers and curing agent (T31) as additives. The isothermal curing reaction process of paint was studied by the differential scanning calorimetry method (DSC), and the curves of curing reaction rate versus time of paint were obtained. The curing reaction kinetics was investigated by using the phenomenological method, and the corresponding parameters of the n-order model, autocatalytic model and Kamal model were determined by fitting the experimental data, respectively. According to the values of R2 and the sum of square due to error (SSE), a suitable curing reaction kinetic model was determined. The curing reaction mechanism of paint was ascertained by the dynamic temperature DSC method and IR spectroscopy (FTIR) method. The results show that the Kamal model can be used to describe the curing kinetics of epoxy resin paint, and the total reaction orders increase from 1.30 to 2.14. The two rate constants increase with the increase of the curing temperature. The activation energy is 90.5832 kJ/mol and 68.3733 kJ/mol respectively, and the pre-exponential factors are 6.521 × 1015 s-1 and 6.3807 × 109 s-1. The curing reaction of paint consists of two steps: the first step is the addition reaction of epoxy group and primary amine or secondary amine; the second step is the etherification reaction of epoxy group and phenolic hydroxyl or alcoholic hydroxyl.
Epoxy resin insulation paint was prepared with epoxy resin (E44) as binders and with proper inorganic fillers and curing agent (T31) as additives. The isothermal curing reaction process of paint was studied by differential scanning calorimetry method (DSC), and the curves of curing reaction rate versus time of paint were obtained. The curing reaction kinetics was studied by using the phenomenological method, the corresponding parameters of the n-order model, autocatalytic model and Kamal model were determined by fitting the experimental data, respectively. According to the values of R2 and the sum of square due to error (SSE), a suitable curing reaction kinetic model was determind. The curing reaction mechanism of paint was ascertained by dynamic temperature DSC method and IR spectrogram (FTIR) method. The results show that the kamal model can be used to describe the curing kinetics of epoxy resin paint, the total reaction orders increase from 1.30 to 2.14. The results also show that the two rate constants increase with increasing curing temperature, The activation energies are 90.5832 kJ/mol and 68.3733 kJ/mol, and the pre-exponential factor are 6.521×1015 s-1 and 6.3807×109 s-1. The curing reaction of paint in two steps, the first step is the addition reaction of epoxy group and primary amine or secondary amine. The second step is the etherification reaction of epoxy group and phenolic hydroxyl or alcoholic hydroxyl.

https://matsc.ktu.lt/index.php/MatSc/article/download/22095/12749

Liang Chen

Papers

Studies on the chemical compatibility of soil-bentonite cut-off walls for landfills.

Curing Kinetics and Mechanism Research of E44/T31 Insulation Paint