Synergistic Improvement of Strength Characteristics in Recycled Aggregates Using Nano-Clay and Polypropylene Fiber.

In order to study the improvement effect of nano-clay and polypropylene fiber on the mechanical properties of recycled aggregates, unconfined compression tests and triaxial shear tests were conducted. The experimental results show that adding polypropylene fibers to recycled aggregates increases the unconfined compressive strength by 27% and significantly improves ductility. We added 6% nano-clay to fiber-reinforced recycled aggregates, which increased the unconfined compressive strength of the recycled aggregates by 49% and the residual stress by 146%. However, the ductility decreased. Under low confining pressures, with the addition of nano-clay, the peak deviatoric stress strength of the fiber-reinforced recycled aggregates first decreased and then increased. When the nano-clay content was 8%, this reached a maximum value. However, under high confining pressures, the recycled aggregate particles were tightly interlocked, so that the improvement effect of the fiber and nano-clay was not obvious. As more nano-clay was added, the friction angle of the fiber-reinforced recycled aggregates decreased, while the cohesion increased. When the content of nano-clay was 8%, the cohesive force increased by 110%. The results of this research indicate that adding both polypropylene fibers and nano-clay to recycled aggregates has a better improvement effect on their strength characteristics than adding only polypropylene fibers. This study can provide a reference for improving the mechanical properties of recycled aggregates and the use of roadbeds.

Designing a microbial fermentation-functionalized alginate microsphere for targeted release of 5-ASA using nano dietary fiber carrier for inflammatory bowel disease treatment.

Patients with inflammatory bowel disease (IBD) always suffer from severe abdominal pain and appear to be at high risk for colorectal cancer. Recently, the co-delivery of targeted drugs and gut microbiota has developed into an attractive strategy. A new strategy using gut microbiota fermentation to overcome the interspace diffuse resistance from the mucus layer to control drug release in inflammatory bowel sites (IBS sites) has not yet been available. Here, we designed an alginate hydrogel microsphere encapsulating bifidobacterium (Bac) and drug-modified nanoscale dietary fibers (NDFs). The hydrogel microsphere is responsible for protecting drugs from acidic and multi-enzymatic environments and delivering drugs to the colorectum. Subsequently, the fermentation of Bac by digesting NDFs and proteins as carbon and nitrogen sources can promote drug release and play a probiotic role in the gut microbiota. In vitro evidence indicated that small-sized NDF (NDF-1) could significantly promote short-chain fatty acid (SCFA) expression. Notably, NDF-1 hydrogel microspheres showed a boost release of 5-ASA in the IBS sites, resulting in the amelioration of gut inflammation and remodeling of gut microbiota in chronic colitis mice. This study developed a controlled release system based on microbial fermentation for the treatment of IBD.

Modification Effect of Nano-Clay on Mechanical Behavior of Composite Geomaterials: Cement, Nano-Silica and Coastal Soft Soil.

To study the modification effect of nano-clay and nano-SiO2 on cement-reinforced coastal soft soil, the effects of the nano-SiO2 and nano-clay on the mechanical properties of cement soil were studied through unconfined compressive and unconsolidated undrained shear tests, and the Duncan-Chang model was used to fit the test results. Results show that adding nano-clay and nano-SiO2 to cement soil improved its compressive and shear strength. The compressive strength and shear strength increased by 18-57% and 3-32%, respectively, with the increase in nano-clay content in a content range of 0-10%. Additionally, nano-clay can enhance the ductility of cement soil. Moreover, nano-clay and nano-SiO2 improve the shear strength by increasing the internal friction angle by 1°-2° and cohesion of 9-25%, and the cement-stabilized coastal soft soil enhanced by nano-SiO2 and nano-clay conforms to the Duncan-Chang model well.