Search Results (5)

It is challenging for mortar to simultaneously enhance the transmission property of water vapor while maintaining excellent waterproofness and impermeability. However, in some applications, both are necessary. Therefore, three different kinds of modifiers, i.e., cementitious capillary crystalline waterproof materials (XYPEX), γ-methacryloxy-propyl-trimethoxy-silane (KH570), and styrene-butadiene rubber latex (SB), are employed to explore how modified mortar can possess excellent waterproofness, impermeability, and the water vapor transmission property simultaneously. Combining characterization techniques, the influencing factors of these three properties are studied. The results indicate that XYPEX promotes the formation of hydration products within pores, improves waterproofness and impermeability, but decreases the water vapor transmission property. KH570 introduces numerous pores ranging from 0.1 to 5 micrometers and enhances the hydrophobicity of mortar; at 1.25% and 2.5% contents, the modified mortar exhibits excellent waterproofness and water vapor transmission property but poor impermeability. SB introduces numerous air pores and forms polymer films; at 20% content, the modified mortar exhibits excellent waterproofness and water vapor transmission property, with impermeability remaining unchanged, making SB a favorable modifier that combines these three properties. Finally, the mechanisms of these three properties are discussed, which provides a theoretical reference for the control of mortar’s waterproofing, impermeability, and water vapor transmission. The selection of modifiers is based on the actual performance requirements. Full article

In recent years, wind energy has emerged as one of the fastest-growing green technologies globally, with projections indicating that decommissioned wind turbine blades (WTBs) will accumulate to millions of tons by the 2030s. Due to their thermosetting nature and high glass/carbon fiber content, the efficient recycling of WTBs remains a challenge. In this study, we utilized solid-state shear milling (S3M) to produce a fine WTB powder, which then underwent surface modification with a silane coupling agent (KH550), and we subsequently fabricated WTB-reinforced polypropylene (PP) composites with enhanced mechanical performance through solid-state stretching. The stretching-process-induced orientation of the PP molecular chains and glass fibers led to orientation-induced crystallization of PP and significant improvements in the mechanical properties of the PP/WTB@550 composites. With 30 wt. % WTB content, the PP/WTB@550 composite achieved a tensile strength of 142.61 MPa and a Young’s modulus of 3991.19 MPa at a solid-state stretching temperature of 110 °C and a stretching ratio of 3, representing increases of 268% and 471%, respectively, compared to the unstretched sample. This work offers both theoretical insights and experimental evidence supporting the high-value recycling and reuse of WTBs through a cost-effective, environmentally friendly, and scalable approach. Due to the enhanced mechanical properties of the PP/WTB composite and the intrinsic waterproofing and corrosion resistance of PP, it is hoped that such a composite would be used in road engineering and building materials, such as geogrids, wall panels, floor boards, and floor tiles. Full article

A new type of waterproofing composite emulsion with high silane content and good economic efficiency was synthesized by sol synthesis. The effects of the amount and proportion of the compound emulsifier, amount of tetraethyl orthosilicate, and mixing time on the properties of the emulsifier were investigated. The optimum conditions for the synthesis of a tetraethyl orthosilicate/isobutyl triethoxysilane emulsion were determined. The composite emulsion was characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive spectrometry, along with a series of microscopic testing techniques. It was verified that the composite emulsion was coated on the surface of the paste to form a hydrophobic protective layer. The results show that the composite emulsion can achieve a permeability and impervious effect after coating the concrete material, and microhardness tests prove that the composite emulsion will not reduce the surface hardness of cement-based materials. Full article

Through penetration depth tests, capillary water absorption tests under different abrasion depths, and capillary water absorption tests of a cement mortar test block with crack damage, a self-prepared, novel, graphene oxide/silane composite emulsion used for the effect of wear or cracking damage was studied. The waterproof performance of concrete and the protective mechanism of a composite emulsion was verified by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The test results showed that the penetration depth of the composite emulsion reached depths greater than 9 mm, which yielded a good waterproof effect; when the concrete was cracked or worn, the composite emulsion still had a stable waterproof performance. It was found that the composite emulsion could form a hydrophobic layer with a certain thickness inside the cement-based material, which explains why the composite emulsion had a good waterproof effect. Full article

There are many types of concrete protection materials, but silane-based protective materials have excellent performance and durability. Experimental usage of silane sol-based waterproof materials is relatively mature and research studies on microscale mechanisms are relatively sparse. In this paper, molecular dynamics simulations are used to explain the microscopic transmission mechanism by analyzing the transport of water molecules and siloxane molecules in the gel pores, the local structure at the interface, and the molecular dynamics in the pores. Firstly, four models with different concentrations were constructed (0, 0.3, 0.6, and 0.9 mol/L). By comparison, it can be found that as the concentration increases, so does the effect of inhibiting the transport of water molecules in the pores. Based on the determination of the concentration, this paper corrects the arrangement. Next, the three commonly used silanes in the experiment were selected for simulation. It was found that octyltriethoxysilane has good stability and a waterproof effect. Among them, octyltriethoxysilane has a longer alkyl chain and is more stable at the interface, which destroys the original spatial correlation and weakens the capillary adsorption. Full article