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Crack propagation simulation is constantly of great significance. This study presents the particle equilibrium method (PEM) to achieve this goal. PEM is based on the idealization of the problem domain as an assemblage of distinct particles, which release interaction forces to their surrounding particles. Once the distance between two particles exceeds the extreme distance, a permanent crack will emerge between them. The function of interaction force describes the mechanical response of elastic and plastic materials. The calculated structure attains its final state to the external load when all the particles reach the equilibrium condition of force. A calculation program is developed based on the proposed method’s theory and is applied to three numerical examples with reliable calculation results. [ABSTRACT FROM AUTHOR]

This paper proposes a new reinforcement structure called soil nets firstly, which is capable of strengthening foundations, slopes, and other structures with better effect than that of soilbags. This proposed geotextile structure typically contains several layers of soil net, which are placed in a unique way. One layer of soil net can be described as a collection of spherical soilbags that are connected together in two directions, one in which they are connected by ropes and another in which they are connected by the PP woven bags that contain the soil. A mechanical property analysis of the soil nets shows that the yield stress of the soil within the soil nets is improved, the tensile capacity of the soil nets is greater than that of the soil with which it is filled, and the equivalent coefficient of interlayer friction between the connected soil nets is larger than that for soilbags. Applications of this new reinforcement structure in the reinforcement of a foundation and a slope are considered, and the corresponding reinforcement effects are calculated. The calculation results demonstrate that the soil nets concept yields efficient reinforcement structures with many advantages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Deep penetrating sealer (DPS) for concrete superficial protection. • The DPS improve the compactness and the water impermeability of the concrete. • Sodium silicate in DPS and C–H in concrete contributes to the increase of C-S-H. • DPS seal the pores with pore size ranging from 20 nm to 130 nm inside the concrete. • The quantity of newly generated C-S-H is higher in the concrete cracks and pores. Deep penetrating sealer (DPS) is water-based permeable crystalline waterproofing coating, and it is widely used to improve the impermeability and durability of cement-based materials. This study investigated the action mechanism of DPS on cement-based materials, especially the microstructure of the newly generated substances and pore evolution in concrete that DPS treated. To explore the action mechanism and permeability of DPS on cement-based materials, experimental specimens were fabricated in this experiment. The specimens included concrete, cement paste, dried DPS, and the product reacted by DPS mixed with saturated calcium hydroxide solution. To test the microstructure, chemical composition, pore structure, and macroscopic permeability of the specimens, scanning electron microscopy, x-ray diffraction, energy dispersive spectrometer, nitrogen absorption, and AutoClam equipment were employed. The experimental and analytical results showed that the calcium silicate hydrate content was increased by the chemical reaction between DPS and cement-based materials. The microstructure of concrete surface then became more densified. The volume of pore with a pore size ranging from 20 to 130 nm inside concrete was decreased, and the water penetration of the concrete was reduced by approximately 75%. This study revealed the action mechanism of DPS and cement-based materials, providing reference for the improvement of DPS and practical engineering application. [ABSTRACT FROM AUTHOR]

The existing studies of the corrosion of reinforced concrete have mainly focused on the interface area and chemical ion erosion, ignoring the specific service environment of the reinforced concrete. In this study, the effect of freeze-thaw damage was investigated via corrosion experiments under different freeze-thaw cycle conditions. Steel reinforcement corrosion mass, ultimate pull-out force, corrosion rate, and bond slippage were chosen as characteristic parameters in the experiments, and scanning electron microscopy (SEM) analysis was used to explain the mechanism of action of freeze-thaw damage on corrosion. The results showed that, under identical corrosion conditions, the mass of steel reinforcement corrosion and corrosion rate increased by 39.6% and 39.7% when comparing 200 freeze-thaw cycles to 0 cycles, respectively. The ultimate pull-out force and bond slippage after 200 freeze-thaw cycles decreased by 73% and 31%, respectively, compared with 0 freeze-thaw cycles. In addition, SEM analysis indicated that microstructure damage caused by freeze-thaw cycles accelerated the corrosion reaction and decreased cementitious properties, leading to decreasing ultimate pull-out force and bond slippage. The effect of freeze-thaw cycles and steel reinforcement corrosion on the macro mechanical properties of concrete is not a simple superposition. [ABSTRACT FROM AUTHOR]