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Superhydrophobic technology in construction can effectively improve the barrier ability of the substrate to harmful water-based erosion media, among which the coating scheme is the most practical choice at present, but it may easily fail due to mechanical damage. Therefore, the current research focus has shifted to the development of internal superhydrophobic materials (ISMs) that maintain stable hydrophobicity even under harsh conditions of use and do not rely on expensive fluor-based surface modifications. In this study, the topological structure of waste denitrification fly ash (FA) was constructed using an innovative method, by precisely controlling the etching medium concentration and the form of FA, a one-step process was developed to create ISM with excellent matrix strength and strong waterproof properties. In this study, the alkaline environment generated by FA hydration was used to induce the silica-hydrogen bond dehydrogenation of polymethylhydrosiloxane (PMHS) and the free ammonium ion deamination to toughen the film; PMHS and liquid phase are used to produce the oil-water phase, and the oil film adheres to the surface of the generated NASH and sodium silicate crystals; The porous inner surface of ISM is formed with hydrogen- and ammonia-induced rough structure; The synthesized ISM retains superhydrophobicity and less compressive strength reduction value, and its superhydrophobicity even at damaged or friction interfaces. The material preparation method provides a good foundation and innovative design concept for the seepage prevention and maintenance of concrete structures, the construction of aerated FA bricks, the preparation of foam insulation materials, and the batch utilization of waste FA. • Denitrification fly ash is prepared into a masonry structure with internal hydrophobicity. • The mechanism of hydrophobic synergism between PMHS dehydrogenation film formation and fly ash etching deamination was revealed. • The internal and external wear resistance of the inner superhydrophobic material has been applied to actual engineering. [ABSTRACT FROM AUTHOR]

The dynamic responses of continuous graded foams are investigated experimentally and numerically. The Voronoi model is employed to construct foam specimens. Graded foams with different gradients and uniform foams with different relative densities are fabricated by the additive manufacturing technique. Experimental results indicate that the gradient distribution notably influences the mechanical properties of foams under a low-velocity impact (about 20 m/s). If the lowest density region is close to one end of a specimen, this end will present a gradually increasing plateau stage in the stress-strain curve. While if the highest density region is placed to one end, this end will exhibit a sharp fluctuation before the gradually increasing plateau stage. Besides, the crushing behaviors of graded and uniform foams are compared to propose an elastic, collapse, plastic-hardening, densification (E-C-PH-D) constitutive model. The E-C-PH-D model can predict the dynamic mechanical properties of graded foams with successive layered deformation. A high-velocity impact (100 m/s) study is also carried out by the numerical simulation. The impact end of graded foams shows distinct higher stresses than the support end due to the shock wave effect. The combined effects of gradient and shock wave on the crushing responses of foams are discussed systematically. Image 1 • The dynamic responses of continuous graded foams are investigated experimentally and numerically. • Under the 20 m/s impact, the gradient distribution notably influences the mechanical properties of graded foams. • An elastic, collapse, plastic-hardening, densification model is proposed to predict the dynamic behaviors of graded foams. • The combined effects of gradient and shock wave on the crushing responses of foams under the 100 m/s impact are discussed. [ABSTRACT FROM AUTHOR]

Due to the hydrophilic nature of the aluminophosphate (AP) adhesives, their application in the wood-based board (WBB) industries is rarely considered. Herein, the AP adhesives with reduced graphene oxide (AP@ r GO) were developed for the construction of hydrophobic surface, mainly for the improvement of the water resistance of AP-based WBB interface as well as their mechanical properties and fire resistance. Results indicated that there is an excellent interfacial adhesion between the AP@ r GO and fibers, making the APW@ r GO achieved a high dry bonding strength of 2.77 MPa. Utilizing the advantages of r GO network with outstanding water resistance, the WBB engineered the comparable wet bonding strength as high as 1.65 MPa, meeting the minimum requirement of the plywood standard stated in GB/T9846.3–2004. Also, AP@ r GO exhibited an excellent fire resistance properties and smoke suppression ability. Benefiting from these remarkable results, the AP@ r GO could be broadly developed for practical applications in related wood-based products. • The synthesis of AP adhesive is featured with simplicity and environment friendliness. • A hydrophobic interface was constructed by using rGO nanosheets. • The AP@GO could provide good interfacial adhesion by the covalent and hydrogen bond connections. • The APW@GO possess favorable mechanical and fire-resistant performance. [ABSTRACT FROM AUTHOR]