Shrinkage Deformation Research Articles

Research on thermal deformation and clearances of oil-free twin screw compressor under cryogenic conditions

The oil-free twin screw compressors have obtained increasing attention in the field of boil off gas (BOG) recovery since they effectively reduce the power consumption and have higher reliability when recovering and boosting BOG. However, the thermal deformation of compressor under cryogenic operating conditions will lead to the change of clearance. The unidirectional thermal-fluid-solid coupling method is proposed in this paper to solve the problem and analyze the thermal deformation of compressor and the changes of each clearance caused by the deformation at different meshing angles in a meshing cycle. It is shown in the results that the deformation of twin screw compressor at low temperatures is a kind of cold shrinkage deformation. The combined effect of the deformation of various components has a significant influence on each clearance. Furthermore, it is reasonable to set the tooth tip clearance of the male rotor, suction end clearance and meshing gap as 0.3 mm, 1 mm and 0.3 mm respectively, which do not cause dangerous working conditions. Inappropriate clearance values lead to friction between parts in the local area. The simulated result of the dangerous friction area in twin screw compressor shows good agreement with the friction area in the compressor test. According to the simulation and test results, the tooth tip clearance of the female rotor is modified to 0.35 mm, and the discharge end clearance is adjusted to 0.1 mm. The results show that the modified compressor can working reliably. This study provides guidance for the design and processing of oil-free twin screw compressors employed in the situation of BOG recovery.

Shrinkage Deformation of Three Different Light Cure Composite Resin Using Image Correlation Method

The study performed were to measured the amount of shrinkage deformation of resin composites with and without bonding agent. The shrinkage defor mation of three types of composite resin (Ecusphere, Densply, CHARISMA) in cavities was studied using image correlation method. The cylindrical cavity in extracted teeth ( premolors) are to examine the shrinkage behavior on the top free surface. The cavities filled with resin after spreading a bonding agent are irradiated using LED unit, also performed on the cavities without bonding agent. One way analysis of variance and MOIRE analysis were used for statistical analysis. The shrinkage behavior was different in the cavities prepared with and without bonding agent. Polymerization of dental composites is characterized by heterogeneous deformation patterns with variable shrinkage values at different locations within the material.

Cohesive element-based chemo-thermo-mechanical multi-field coupled cracking simulation of early-age concrete

Due to the intense exothermic hydration process, early-age concrete undergoes restrained shrinkage deformation, which can easily lead to cracks in concrete structures during construction. In order to accurately predict the adverse effects of early-age concrete cracking behavior, a cohesive element-based chemo-thermo-mechanical multi-field coupled cracking model of early-age concrete is proposed in this study. Parametric analysis shows that by selecting appropriate gap conductance, constitutive thickness, mesh size, and viscosity coefficient for the cohesive elements, the multi-field coupled cracking model can successfully simulate the entire cracking process of early-age concrete, and it has the ability to obtain crack development behavior based on the real displacement field jumps, coordinates, and damage of cohesive elements. The validation of the numerical examples reveals the competing mechanisms between thermal expansion and autogenous shrinkage in early-age concrete and accurately predicts the cracking strain, region, time, and width (within an order of magnitude) as reported in the literature.

On in-plane crushing behavior of an improved double-arrow auxetic metamaterial with two-step deformation mode

An improved double-arrow auxetic honeycomb metamaterial (MDAH) with two-step deformation mode was proposed and manufactured, and its in-plane crushing behavior was studied experimentally, numerically and theoretically. Quasi-static compression experiments were carried out to obtain the deformation modes and stress-strain response. The reliability of the numerical simulation was verified by experimental results. Experiments and numerical simulations have shown that MDAH exhibits a two-step deformation mode of first buckling deformation and then shrinkage deformation, with double-plateau stress characteristics. The provided theoretical results of plateau stresses are in good agreement with experimental and numerical simulation results. The effects of geometric parameters on the in-plane crushing behaviors of MDAH were further discussed through numerical simulation and theoretical analysis. The results indicate that the multi-step deformation mode of MDAH is related to the thickness and angle design of inclined rod. A suitable design can result in a stable two-step deformation mode and exhibit a negative Poisson's ratio effect. The MDAH structure has the characteristic of Poisson's ratio from positive to negative. The deformation mode and mechanical response can be regulated by changing the geometric parameters of MDAH. Compared to traditional double-arrow structures, MDAH has better energy absorption capacity. The present research can provide a new design strategy of auxetic metamaterial with deformation mode conversion and improved energy absorption efficiency.

Study on the mechanical properties and strength formation mechanism of high-volume graphite tailings concrete

Graphite tailings and coal gangue (CG) are solid wastes produced by mines. The large accumulation of surface materials poses great harm globally, and resource utilization is an urgent problem to be solved. In this paper, steel slag (SS), granulated blast furnace slag (GGBS), and fly ash (FA) are used as binder materials. Graphite tailings sand (GTS) is used as a fine aggregate. Using coal gangue and natural gravel as coarse aggregates, high-volume tailings aggregate concrete was prepared by the alkali excitation method. The strength formation mechanism of concrete was analyzed by combining scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The results showed that with increasing tailings replacement rate, the strength of concrete containing natural gravel and coal gangue as coarse aggregates gradually decreased. The strength of coal gangue aggregate concrete is 10-15 MPa lower than that of natural gravel aggregate concrete. The uniaxial compressive failure of GTS concrete is divided into three stages: quasielasticity, stable expansion, and critical stress. A small amount of steel scoria (less than 30 %) can provide a good calcium ion (Ca2+) environment for the hydration reaction. The concrete hydration products are mainly calcium silicate hydrate (C-S-H) gel, sodium aluminosilicate hydrate (N-(A)-S-H) gel, ettringite (AFt), etc., and the formation of calcium silicate hydrate C-S-H gel and N-(A)-S-H gel can inhibit the cracks that proceed by shrinkage deformation and improve the durability of concrete. GTS concrete can reduce carbon emissions and solidify some of the harmful substances of raw materials.

Slippery hydrogel with desiccation-tolerant ‘skin’ for high-precision additive manufacturing

Hydrogels inevitably undergo dehydration, structural collapse, and shrinkage deformation due to the uninterrupted evaporation in the atmosphere, thereby losing their flexibility, slipperiness, and manufacturing precision. Here, we propose a novel bioinspired strategy to construct a spontaneously formed ‘skin’ on the slippery hydrogels by incorporating biological stress metabolites trehalose into the hydrogel network, which can generate robust hydrogen bonding interactions to restrain water evaporation. The contents of trehalose in hydrogel matrix can also regulate the desiccation-tolerance, mechanical properties, and lubricating performance of slippery hydrogels in a wide range. Combining vat photopolymerization three-dimensional printing and trehalose-modified slippery hydrogels enables to achieve the structural hydrogels with high resolution, shape fidelity, and sophisticated architectures, instead of structural collapse and shrinkage deformation caused by dehydration. And thus, this proposed functional hydrogel adapts to manufacture large-scale hydrogels with sophisticated architectures in a long-term process. As a proof-of-concept demonstration, a high-precision and sophisticated slippery hydrogel vascular phantom was easily fabricated to imitate guidewire intervention. Additionally, the proposed protocol is universally applicable to diverse types of hydrogel systems. This strategy opens up a versatile methodology to fabricate dry-resistant slippery hydrogel for functional structures and devices, expanding their high-precision processing and broad applications in the atmosphere.

ИССЛЕДОВАНИЕ ПОЛЗУЧЕСТИ СТАЛЕЖЕЛЕЗОБЕТОННЫХ ОБРАЗЦОВ

The paper presents the results of investigation of creep and shrinkage of steel-reinforced concrete specimens. For this purpose, parallel tests of specimens made of the same class of concrete but with different reinforcement were carried out. Concrete specimens, specimens reinforced with bar reinforcement frames and steel reinforced concrete specimens with external sheet reinforcement were investigated. The tests were carried out in climatic rooms using spring setups to maintain a constant load acting on the specimens over time. The load on the specimens was selected based on the equality of stresses in the concrete in all series of specimens. The specimens were tested both waterproofed and non-waterproofed, and the effect of waterproofing coating on shrinkage and creep strains was evaluated for different series of specimens. A system was developed to capture information. which allows, in addition to longitudinal shrinkage and creep deformations, to determine transverse deformations, longitudinal deformations along the faces of the specimen to determine the influence of reinforcement and steel of the outer plate, to evaluate the change in longitudinal deformations from the center of the specimen to its edges, to evaluate separately the deformations of concrete and steel plate in steel-reinforced concrete specimens. The analysis of the results allowed a comparative assessment of the influence of conventional bar reinforcement as well as steel sheet of steel-reinforced concrete specimens on creep and shrinkage deformations; the influence of waterproofing coating on the test results in different series was also assessed. Based on the results of this work, extended requirements for experimental and theoretical studies of steel-reinforced concrete specimens with external sheet reinforcement to determine their design stiffnesses were formulated.

Energy efficiency of timber-frame buildings in cold climates

Ensuring human life in harsh cold climate conditions is one of the priority objectives for the development of the Arctic states. Among numerous building structures used in the construction of energy-efficient buildings, wood-frame panels occupy one of the leading places in the world. They have inherent positive characteristics such as versatility, manufacturability, lightness, high thermal protection qualities and relatively low cost. The main features include a high dependence of their fire resistance and energy efficiency on the choice of materials and structures. In the paper to improve energy efficiency and fire resistance of timber-frame buildings the method of two-layer thermal insulation in permanent formwork made of non-combustible glass magnesite boards with the use of heterogeneous thermal insulation materials is proposed. These include polystyrene foam with a low coefficient of thermal conductivity and non-combustible insulating foam concrete. To substantiate the increase of energy efficiency of the enclosing structures, the results of thermal calculation are given, thermograms of field inspection of the quality of thermal insulation are shown. At rational selection of materials and construction the energy efficiency of the offered multilayer wooden-frame wall (thermal resistance 5.66 (m2 × °C)/W) is increased almost two times (by 1.82) in comparison with a single-layer wall from monolithic foam concrete of similar buildings in conditions of St. Petersburg. The results of experimental research on improving the technology of obtaining heat-insulating foam concrete with improved indicators of shrinkage deformation, strength and curing processes are presented.

Adaptive positioning technology of film cooling holes in hollow turbine blades

Film cooling technology is widely used in hollow turbine blades of aero-engine with a high thrust-to-weight ratio. The positioning accuracy of film cooling holes directly affects the uniformity and adhesion of the cooling film on blade surfaces. Two main factors affect the positioning accuracy of film cooling holes, i.e., the profile deformation of the blades during manufacturing and the blade clamping error in computer numerical control equipment. The positioning technology of film cooling holes has rarely been investigated. In this study, an adaptive positioning method is proposed to provide a reference for innovative research in this field. First, this study proposes a method for measuring and compensating blade clamping error based on the point cloud data of the entire blade surface obtained with optical scanning equipment by combining the rigid-body transformation theory and three-dimensional point cloud matching method. Second, owing to the complex overall deformation of the blade surface, this study innovatively focuses on the deformation of each slice from a local perspective. Furthermore, the deformation of each slice is decomposed into bending, torsion, and uneven shrinkage. The bending and torsion deformations are compensated based on the two-dimensional rigid-body matching method, while the remaining uneven shrinkage deformation is compensated by the position mapping method. The effectiveness and accuracy of the proposed method are qualitatively and quantitatively verified by the adaptive positioning results of film cooling holes in actual and test blades. The maximum spatial position and angle deviations are 0.0561 mm and 0.6946°, respectively.

Enhancing adhesive strength and durability: Exploring the benefits of upconversion particle-assisted near-infrared photopolymerization

Adhesives with exceptional strength and long-lasting durability are of paramount importance in various industries and applications by providing efficient bonding solutions, enabling the assembly of diverse materials. However, enhancing the adhesion strength of photocurable adhesives poses a significant challenge due to the presence of shrinkage stresses. In this work, upconversion particle-assisted near-infrared photopolymerization (UCAP) was used to cure adhesives, and the effects of curing condition, such as irradiation time and particles content, on adhesive properties were investigated. The adhesives cured through UCAP demonstrated a notable enhancement in shear strength, with an observed increase of approximately 25 % compared to the specimens cured by UV irradiation. Through a comprehensive analysis of the shrinkage deformation and rheological behavior during curing, this study successfully demonstrated the effects of UCAP in reducing shrinkage stress and alleviating the peeling tendency. Moreover, the reduced deformation of UCAP specimens compared to UV-cured specimens can be attributed to the increased gel point conversion in the UCAP process. The improved adhesive properties observed through UCAP indicates the potential for widespread utilization of UCAP technology.

THE EFFECT OF SHRINKAGE CONTACT STRESSES ON THE ADHESION STRENGTH OF THE WATERPROOFING COMPOSITION AND THE «OLD» CONCRETE

The paper is devoted to the study of the effect of shrinkage contact stress on the bonding strength of the waterproofing composition of fine-grained cement concrete and «old" concrete. In order to obtain a strong contact when adhering old and new concrete, it is necessary to minimize the amount of internal stress in it. The cause of concrete shrinkage during the initial curing period is the reduction of the cement stone gel, the amount of free water that is consumed by evaporation and hydration of the cement. The semi-bound water (film water) surrounding the gel particles is then consumed. This causes the gel particles to come closer together and shrink further. In addition, the capillary pressure in the pores is very significant and increases with decreasing pore size. Since the micropores are scattered in the cement stone in different directions, the pressure, balancing each other, acts as a comprehensive compression, which also causes volumetric deformation. With further drying of the concrete, the moisture gradient decreases, the growing crystal growths provide more and more resistance to internal pressure and the shrinkage deformation gradually subsides. Thus, the more intensive the hydration processes in the waterproofing coating and the more crystalline hydrates are formed at earlier curing times, the earlier the resistance to comprehensive compression in the coating will be, and as a result, the crack resistance of the coating and the strength of its adhesion to the «old» concrete will increase. As a result of the research carried out in this work, it was found that the compaction of the waterproofing composition, which helps to reduce internal stresses during curing and thus increases the amount of its adhesion to old concrete, is achieved by introducing a finely ground calcium carbonate filler and a complex of chemical water-soluble additives of the second class. The mineral filler and chemical additives allow for the additional synthesis of etringite, calcium hydrocarbonate and calcium hydrochloraluminate, low-base calcium hydrosilicates, and calcite during cement hydration in its pores and capillaries. The developed permeable waterproofing composition in the form of a mortar has high adhesion strength to old concrete and can be used in repair, restoration and protection of building structures, buildings and structures from external influences related to the water environment.

Performance of brick masonry prisms retrofitted with fiber reinforced lime-based grouts

Lime-based grouts have been widely used for the consolidation of historic masonries, whereas additives of various origin and proportion are used to enhance their properties at fresh and hardened state. Testing their efficiency includes analysis of their fresh and physico-mechanical properties, as well as experimental assessment of their applicability in masonry prisms and wallettes. In the present study, four grout compositions based on hydrated lime and natural pozzolan, including 0.1% v/v glass and polypropylene fibers, were manufactured and tested. They were injected in brick masonry prisms which were previously partially loaded to compression. Macroscopic observations and measurements of pulse velocity and compressive strength were performed prior and after grouting, in order to investigate the prisms behavior and the efficacy of the fiber reinforced lime-pozzolan grouts. According to the results, fibers maintained the grouts fresh properties, improving volume stability (shrinkage deformations were decreased) and long-term mechanical characteristics. The masonry prisms showed a pulse velocity increase after grouting, while compressive strength was also enhanced, especially in the case of 3 mm glass fibers addition. Generally, it was asserted that the application of fiber reinforced lime-based grouts could be feasible in the case of historic masonries restoration, rendering their study a well promising field.

Study on the mitigation of drying shrinkage and crack of limestone powder cement paste and its mechanism

To investigate the reasons for the mitigation of drying shrinkage but earlier cracking in limestone powder cement paste, various admixtures such as fly ash, metakaolin, super-absorbent polymer, and expansion agent were selected for the above-mentioned experiments. The effects of mixing two admixtures on the drying shrinkage deformation and crack resistance performance of the limestone powder-cement paste was studied. Additionally, hydration exotherm, hydration products, microscopic morphology of samples were analyzed to understand the underlying mechanisms. Based on the hydration process, the addition of fly ash and metakaolin can promote the formation of carbon aluminate in the reaction system, thereby reducing the porosity. Fly ash is more beneficial for the hydration heat peak value of cement paste, effectively eliminating temperature strain. The results indicate that effects of mixing two admixtures on the improvement of drying shrinkage and crack resistance of limestone powder cement paste are much better than using a single admixture. Among them, the combination of metakaolin and expansion agent shows the best overall mitigating effect on the drying shrinkage and crack resistance of limestone powder cement paste. This compound admixtures reduces the drying shrinkage of the paste by approximately 30% and delays the cracking time of the specimens by 34.4 h.

Investigations on the Suitability of Alternative and Supplementary Cementitious Materials to produce High Performance Aerogel Concrete

AbstractHigh Performance Aerogel Concretes (HPAC) are produced by embedding silica aerogels in high‐performance matrices, which were previously based on finely ground Portland cement CEM I 52.5 R and microsilica. On the one hand, this ensured a comparatively high compressive strength, but on the other hand it was associated with large shrinkage strains and a high global warming potential (GWP). In the following, approaches are presented on how these disadvantages can be counteracted by replacing Portland cement with alternative (ACM) or supplementary cementitious materials (SCM). In the experimental investigations, calcium aluminate cement, calcium sulfoaluminate cement, calcium sulfoaluminate belite cement and a CSH phase binder were used as ACMs; limestone powder, calcined clay, fly ash, glass powder, rice husk ash, brick dust and ground granulated blast‐furnace slag were used as SCMs. Based on extensive fresh and hardened concrete tests, it could be shown that with the (partial) replacement of Portland cement by ACMs or SCMs, High Performance Aerogel Concretes can be produced that have significantly reduced shrinkage deformations and a lower GWP with an unchanged good relationship between compressive strength and thermal conductivity.

A Numerical Simulation and Multi-objective Optimization for the Plastic Injection Molding of a Centrifugal Pump Casing

Plastic pumps are used to efficiently move liquids within aquaculture systems and seafood processing facilities. Commonly, the centrifugal pump casing is fabricated by plastic injection molding technology. In the plastic injection molding process, the control parameters are essential to the success of plastic molding product fabrication. This study aims to optimize process parameters for the quality of centrifugal pump casing during plastic injection molding using a combination of response surface methodology (RSM) and the NSGA-II method. Firstly, the L27 orthogonal array design of the experiment method is used, which has four input variables, including plastic temperature, mold temperature, cooling time, and injection time (filling time and packing time). The output responses of the injection molding process to be evaluated are the warpage and shrinkage deformation of the molded product. After obtaining data, the RSM model is applied to describe the relationship between the input and output variables. Finally, multi-objective optimization uses the NSGA-II method for the best product quality. The results show that the optimized parameters for injection molding of the centrifugal pump casing are a plastic temperature of 200°C, mold temperature of 65°C, cooling time of 25s, and injection time of 10s with warpage of 0.868 mm, and shrinkage of 10.104mm.

Optimization Method of Multi-parameter Coupling for a Hydraulic Rolling Reshaper Based on Factorial Design

A hydraulic rolling reshaper is an advanced shaping technology with superior protection for casings, and the structural parameters of the reshaper affect its shaping effect on deformed casing directly. To improve the shaping capacity of the reshaper, a multi-parameter coupling optimization method of hydraulic rolling reshaper is proposed to optimize the design of the factors with significant influence under the premise of screening multi-structural parameters. In this paper, according to the working principle of the reshaper, considering the contact nonlinearity between the hydraulic rolling reshaper and deformed casing, as well as the material nonlinearity of the casing, a parametric finite element model of the hydraulic rolling reshaper repairing the shrinkage deformation of casings was developed. The remarkable factors were screened by factorial design, the sample points were generated by optimal Latin hyper-cube design (OLHD), and the response surface models were established by stepwise regression. Therefore, with the maximum plastic deformation of casings as the objective function, the maximum equivalent stress, residual stress, and the plastic deformation of casings as the constrained conditions, an optimized mathematical model for a reshaper was constructed, and the genetic algorithm (GA) is performed to obtain the optimal combination of parameters. The results showed that the optimal reshaper made the shaping process safe and effective, the plastic deformation of casings after single shaping was increased by 11.38 %, and the shaping effect was better (96.48 %), which can effectively improve the safety performance and shaping ability of the reshaper.

Study on the Influence of Shrinkage-Reducing Materials on the Volume Stability of Shotcrete with a Fluorine-Containing Alkali-Free Accelerator.

In contrast to ordinary concrete, shotcrete exhibits greater shrinkage deformation. The utilization of an aluminum fluoride alkali-free accelerator (AF) is prevalent in tunnel engineering, attributed to its economical nature and fast setting and hardening. Currently, there is a dearth of research on the volume stability of aluminum fluoride accelerators, and no relevant studies have been conducted on the application of shrinkage-reducing materials in shotcrete using an aluminum fluoride accelerator. With the use of an aluminum fluoride accelerator, the early strength of shotcrete is reduced, and the addition of a shrinkage-reducing agent (SRA) and super-absorbent polymer (SAP) can also lead to a further reduction in the early strength of concrete. Therefore, this study aims to investigate the influence of these two shrinkage-reducing materials (SRA and SAP) on the workability and mechanical properties of shotcrete. The primary focus of this research is to determine the better compensation effect of the two shrinkage-reducing materials. To accomplish this, the study focuses on assessing the setting time, compressive strength, and volume stability of shotcrete that has been mixed with an aluminum fluoride accelerator using SRA and SAP. Additionally, we also aim to explore the hydration and shrinkage compensation mechanism of these shrinkage-reducing materials on shotcrete by conducting a microscopic test analysis.

Mechanical property, volume stability and microstructure of lightweight engineered cementitious composites (LECC) containing high-volume diatomite

Due to the requirement of sustainable development, the number of coal-fired power plants has gradually decreased, resulting in insufficient supply of traditional supplementary cementitious materials (SCMs). In this study, diatomite is proposed to replace fly ash in the lightweight engineered cementitious composites (LECC), and mechanical properties, shrinkage deformation and microstructure of diatomite-modified LECC (D-LECC) are investigated. The results show that the incorporation of diatomite reduces compressive strength, tensile strength and tensile strain capacity of LECC because of reduction of hydration degree and increase of porosity. Meanwhile, incorporating extra water (EW) into diatomite further increases the amount of hydration products and compactness of D-LECC, so the D-LECC with EW has higher compressive strength, tensile strength and less tensile strain capacity in comparison without EW. Besides, compared to reference specimen, autogenous shrinkage of D-LECC increases due to the reduction of mixing water. As the EW is absorbed in diatomite, the autogenous shrinkage of D-LECC reduces because of the internal curing effect of EW. The 14-d autogenous shrinkage of F50E is 1151 μm/m, which reduces by 68.3 % of the autogenous shrinkage of F50. In the microstructure, incorporating diatomite decreases hydration degree and increases the porosity of sample. Meanwhile, incorporating EW into diatomite improves hydration degree and refines pore structure of D-LECC sample. Therefore, it is found that diatomite absorbing EW has a great potential to be incorporated into the LECC for solving the shortage reserves of traditional SCM.

Study on valley deformation of high arch dams based on nonlinear rheological damage model

The scale of the high arch dam project is large, and the water level is high. The construction and water storage effect will significantly impact the rock mass of the high slopes on both sides, especially on the structural planes such as internal faults. Based on the Jinping Ⅰ high arch dam, an improved Nishihara rheological damage model was established to address the phenomenon of valley shrinkage deformation. The stress and deformation states of the rock mass and dam in the reservoir area were calculated, and the results were compared with the conventional elastic–plastic finite element method. The results indicate that the improved parallel Nishihara rheological damage model can better conform to the deformation properties of the internal structural planes of the rock mass, and the calculation results using this model are closer to the actual deformation situation. When considering the structural plane's rheological characteristics, the valley shrinkage deformation law is consistent with the conventional elastic–plastic finite element calculation results, but the magnitude is too large. In addition, when considering the rheological characteristics of the structural plane, the increase in valley shrinkage deformation value further increases the stress and deformation of the high arch dam, which can better reflect the dam's working behavior and ensure the dam's safe operation.

Performance of recycled aggregate concrete (RAC)-filled steel tubular (FST) members and K-joints under lateral impact

A series of tests are conducted on 26 recycle aggregate concrete (RAC)-filled steel tubular (FST) members and 25 RAC-FST K-joints on a drop hammer rig. Salient parameters considered in the experimental program include the axial load ratio, the replacement ratio of recycled coarse aggregate (RCA), the height of the hammer and the application of combined corrosion and sustained loading, et al. The shrinkage and creep deformation of core RAC is measured for 185 days, and the influence of key parameters on the structural performance of both RAC-FST members and K-joints are analyzed. A finite element (FE) model is established and verified against the test results. Considering the effects of combined chloride corrosion and sustained loading, the FE model is successively employed to investigate the behaviour of RAC-FST members and K-joints under lateral impact, including the failure mode, the time history relationships of impact load and deflection, the distribution of internal force and stress, et al. The axial compression performance of the member and the chords of K-joints after being subjected to combined loading is evaluated. On the basis of the parametric analysis, simplified models considering the effects of chloride corrosion and sustained loading are obtained to calculate the dynamic flexural capacity of the RAC-FST members and the chords of RAC-FST K-joints under impact loads.