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The Acoustic Emission (AE) and Dynamic Identification (DI) techniques were applied simultaneously, in an original way, to examine the stress dependent damage progress in pre-notched concrete beams tested in four-point bending. The damage mechanisms were characterized by analyzing the AE signals registered during the tests, conducted by increasing the specimen’s vertical deflection. In particular, the dominant fracture mode was identified, and correlations between dissipated and emitted energies were investigated. Moreover, variations in the natural bending frequencies, produced by the crack advancement under loading, were detected and put in relation with the cumulated AE energy. Two different types of piezoelectric (PZT) sensors, operating in well distinct frequency ranges, were used to measure AE and modal signals. This study may be of interest with an outlook on possible correlations between a multi-parameter structural monitoring and the solution of inverse problems by numerical models.

• A new modified adhesion test by considering cyclic temperature effect is proposed. • The cyclic temperature effect is simulated through 3 hot-cold cycles. • The total dissipated energy is proposed to evaluate the effect of aging on sealant adhesion. Due to the influences of installation and field environment, the adhesion failure usually occurs during the actual application of sealants. But current specification methods do not adequately consider the installation aging and field cyclic temperature effect on the adhesion of sealants. Hence, a new modified adhesion test method was proposed to quantitatively evaluate the effect of aging on the adhesion of three types of sealants. The cyclic temperature effect was simulated through 3 hot-cold cycles and the aging during installation was modelled through the short-term thermal aging. Based on the modified adhesion test, an evaluation method and 3 evaluation indexes were proposed to quantitatively evaluate the adhesion of sealants. Further, based on energy method, total dissipated energy (E t) was proposed and used to quantitatively evaluate the effect of aging on sealant adhesion. Then the aging indexes of several evaluation indexes were proposed to analyze the effect of aging on the adhesion of sealants. Finally, a comparison was made between current specification bond test and the modified adhesion test and the advantages of modified adhesion test were demonstrated. The results show that short-term aging had a significant weakening effect on the maximum tensile stress (σ n) and made the tensile separation stiffness (K n) of different sealants change irregularly. The conventional adhesion evaluation index, growth rate of tensile separation stiffness (G s), is not suitable for evaluating the effect of aging on sealant adhesion. Compared to G s , the E t index reflects the accumulation of dissipated energy during the whole test process, and improves the stability of the overall evaluation. The evaluation index E t and the corresponding aging index AI E were recommend to quantitatively evaluate the effect of aging on sealant adhesion. Due to the effect of short-term aging, the adhesion of three types of sealants under the cyclic temperature effect decreases by 15%∼35%. One recommend that the effect of short-term aging should be considered in the adhesion evaluation of sealants. [ABSTRACT FROM AUTHOR]

The equation of motion for the response of SDOF systems is presented in terms of energy for a general class of hysteretic relationships that include stiffness degrading inelastic and bilinear elastic behavior, for systems subjected to earthquake ground motions in the presence or absence of P-delta effects. The evaluation of expended energy is presented in a continuous form, along with the evaluation of input energy associated with second-order geometric effects. Examples illustrate the dissipation of energy through damping and hysteretic response and the increase in input energy associated with P-delta effects. [ABSTRACT FROM AUTHOR]

Part I of this paper showed that under biaxial tension–compression load the energy dissipation capacity of fibre reinforced concretes (FRC) is up to 30% lower than under uniaxial tension load. In this part, the extent of the fracture process zone (FPZ) was studied with the acoustic emission technique and the decrease of the energy dissipation will be explained. It was found that plain concrete specimens have generally narrower/smaller FPZ compared to FRC specimens under both uniaxial tension and biaxial tension–compression load case. Under biaxial tension–compression load for both unreinforced and fibre reinforced specimens the FPZ tends to become slightly wider compared to the uniaxial tension load case. However with increasing biaxial compression stress ratios the specimens energy absorption capacity decreases. In case of biaxial load, the bond between the fibre and the matrix zone is affected by the lateral compression stresses, resulting in a smaller FPZ compared to the uniaxial load. This is believed to be the main reason for the lower dissipated energy. [ABSTRACT FROM AUTHOR]

The objective of this research was to analyse the differences in the dissipated energy under uniaxial tension and biaxial tension–compression load of fibre reinforced concretes using the Wedge Splitting Test. Under biaxial load the specimens were subjected to compressive stress ratios from 10% to 50% of the concrete compressive strength perpendicular to the direction of the tensile load. Under biaxial tension–compression load the energy dissipation capacity of the specimens decreases compared to the uniaxial tension load case on average 20–30%. It is believed that the decrease is a result of the damage mechanism of the concrete matrix and deterioration of the fibre–matrix and/or aggregate–cement paste interfaces in case the section is additionally loaded with compression stresses. This indicates that dimensioning of concrete elements under biaxial stress states using material parameters obtained from tests conducted on specimens under uniaxial tensile load is unsafe and could potentially lead to a non-conservative design. In the second part of this paper the extent of the fracture process zone under uniaxial tension and biaxial tension–compression load will be examined with the Acoustic Emission technique and the reasons for decrease of the energy dissipation capacity under biaxial load will be further discussed. [ABSTRACT FROM AUTHOR]

In this work, the response and dissipated energy of the well-known Bouc-Wen model are examined in detail. New analytical and numerical solutions are derived using a generic model formulation without any parameter constraints. Theoretical issues, such as the inexistence of an elastic domain and the evaluation of the residual deformation after a loading-unloading cycle are addressed by means of analytical equations. This work capitalizes on previous findings by the author and recent advancements in the field to target both theoretical and numerical implementation issues. [ABSTRACT FROM AUTHOR]

The objective of this research study was to conduct a laboratory investigation of reclaimed asphalt pavement (RAP), containing a high percentage of natural sand mixtures, in terms of moisture susceptibility, permanent deformation, and fracture energy with respect to the use of both hydrated lime and liquid antistripping additives (ASAs). The experimental design included one base binder, one natural sand, three ASAs, two aggregate sources, two RAP contents, and two surface mix types (Types B and C). A total of 12 mixtures were investigated and a total of 160 specimens were made and tested in this study. The test results indicated that the indirect tensile strength (ITS) and tensile strength ratio values of RAP with 20% natural sand showed that hydrated lime and liquid ASAs could be used to resist moisture damage, regardless of the aggregate source. In addition, the rut depths of Surface C mixtures were generally less than 5 mm, irrespective of aggregate source and ASA type. Moreover, various ASAs, aggregate sources, and surface types slightly affect the dissipated energy of wet samples. Furthermore, there are some general correlations between dissipated energy and its corresponded ITS values, in terms of aggregate source and surface type used in this study. [ABSTRACT FROM AUTHOR]

Numerous wear equations based on distinct models to predict the wear, are available in the literature. However, most of these models require properties that usually are not easy to obtain, and simple models derived from the Archard equation remain the main base to use in practical situations, by engineers and designers, to predict product life. This equation predicts that wear is a linear function of sliding distance and load, which agrees with several real cases. One important aspect that is neglected in laboratory, in the evaluation of wear rates, is that the tests performed under conditions of uniform contact do not reflect what very often happens with equipments that have operating regimes that can vary from periodic or random and change those contact conditions. Because the additivity is a property of linear functions, this work aims to discuss the application of the additivity property to the Archard equation. A pin-on-disc technique was used to test a hard steel 100Cr6 sphere against a gray cast iron disc. These materials were selected to minimize the adhesion wear component. Different contact conditions, namely normal loads and sliding distances, were investigated to establish a linear basic equation to test as a model to take into account the accumulation of damage resulting from the step loading conditions studied, applying successive different blocks of load. Friction was measured along the experiments and an energetic model was discussed as an alternative way to model the wear. At the end of the tests SEM observations were used to evaluate the wear mechanisms based on the wear scar morphologies. [ABSTRACT FROM AUTHOR]

Piles in structural foundations that are used to load transmissions from the main structure to the bed are generally subjected to lateral loads. In order to study the effect of concrete pile geometry on its structural behavior, several models with different shapes and dimensions were selected and analyzed, assuming nonlinear behavior for soil. The behavior of the pile models was studied, evaluated and tabulated using numerical analysis under different conditions, such as changes in the pile geometry and shape, and soil properties. Therefore, the displacements of pile heads situated in granular soil, with different compaction levels, under a lateral load, were studied in loading and unloading cycles. The dissipated energy was calculated based on pile head displacements in different load steps in the first and second cycles of loading. The "performance index" is defined as the ratio of dissipated energy to the maximum pile head displacement, and these two factors effects on different pile model behavior were compared, concurrently. It was observed that piles with rectangular cross sections and smaller width have the maximum dissipation of energy, and the minimum displacement occurs in dense soil. [ABSTRACT FROM AUTHOR]

In this study, the effects of mechanical and geometrical properties of the adhesive layers and mechanical properties of the metal layers on low-velocity impact behavior of adhesively bonded metal laminates (ABML) were investigated. The contact force, the transverse displacement, the contact duration, and the dissipated energy were considered as the main structure responses under impact loading. To study the effects of mechanical and geometrical properties of adhesive layers on low-velocity impact behavior of ABML, two different adhesive materials and two different adhesive thicknesses were considered. The results showed that the contact force was more depended on the adhesive thickness and nearly unaffected by the adhesive material, whereas the dissipated energy was more depended on the adhesive material rather than the adhesive thickness in case the overall structure thickness was remained fixed. To determine the effects of material parameters of the metal layers including the yield stress, the elastic modulus, the density, and the tangent modulus on the impact behavior of ABML, finite element analyses were carried out. The results showed that increasing the number of metal layers in a constant total thickness caused decrease of the total contact force and increase of the contact duration and transverse displacement of the structure due to more widespread plastic deformation occurred in the layers. The material yield stress and Young’s modulus were the most influencing material parameters on the mechanical behavior of ABML under low-velocity impact loading. The finite element models were well validated against the experimental and numerical results. [ABSTRACT FROM PUBLISHER]

Copyright of Jianzhu Cailiao Xuebao: Journal of Building Materials is the property of Journal of Building Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The identification of the modal parameters from frequency response functions is a subject that is not new. However, the starting point often comes from the equations that govern the dynamic motion. In this paper, a novel approach is shown, resulting from an analysis that starts on the dissipated energy per cycle of vibration. Numerical and experimental examples were used in order to assess the effectiveness of the proposed method. It was shown that, for lightly damped systems with conveniently spaced modes, it produced quite accurate results when compared to those obtained from the method of the inverse. The technique also proved to be simple enough to be used for quick estimates of the modal damping factors. Finally, this paper is a contribution to modal analysis and identification methods, as the developed technique has never been proposed before. [ABSTRACT FROM AUTHOR]

Many researchers have studied building pounding to calculate the dissipated energy and impact force between two buildings during an earthquake. In this paper, a new equation is proposed to measure the impact force and energy dissipation. The results based on the proposed equation are compared with the results of available equations. Using a suggested link element, a new formula is presented to calculate the impact force and energy dissipation. In order to evaluate the results of dissipated energy, a new relation between CR and impact velocity is also suggested. Since there is a need to have a reference curve to select impact velocity, based on the coefficient of restitution, several impact velocities and CRs were evaluated. By using the latter curve, results could be evaluated. A new equation of motion is assumed to select the best impact velocity and coefficient of restitution. Finally, based on the coefficient of restitution and using the steady-state response of a single degree of freedom system, due to external force, a new equation of motion is suggested to calculate the impact damping ratio. [ABSTRACT FROM AUTHOR]

Highly concentrated colloidal suspensions exhibit a discontinuous shear-thickening behaviour. The transition from a low to a high viscosity state is associated to a large energy dissipation. This effect could find applications in structural damping while the viscosity increase brings added stiffness. In the present work, highly concentrated suspensions of monodisperse spherical silica particles in polyethylene glycol were selected for their strong thickening at low critical shear rates. Their damping properties were characterized by measuring the energy dissipated per cycle at low frequency (below 2 Hz) during oscillatory tests using a rheometer. The influence of parameters such as particle concentration, size and frequency was investigated. Damping was found to overcome that of benchmark elastomeric materials only in high frequencies and high strain domains. [ABSTRACT FROM AUTHOR]

In this work, Valanis model parameters, and their variation with bolt preload, were determined for a bolted lap joint, which consisted in two steel plates held together by a metric 12 screw. For this purpose, a series of transitory non-linear analyses were performed on the basis of a three dimensional finite element model of the bolted lap joint subjected to varying bolt preloads and tangential displacements. Curve fitting of hysteresis cycles obtained from numerical simulations allowed determination of Valanis model parameters as well as assessment of bolt preload influence on these parameters. In addition, the present numerical simulations provided information about the evolution of the contact state from stick to slip regimes between the bolted plates, reflecting the non-linear behaviour of the joint. Quasi-static tests at several preloads and tangential displacements conditions were conducted to validate Valanis model parameters previously obtained from numerical simulations. The present findings provided detailed information about the evolution of the aforementioned Valanis parameters with bolt preload. Thus, we confirmed that equivalent stiffness values corresponding to the macro-slip regime as well as the upper limit of the sticking regime ( E t and σ 0 , respectively) are highly influenced by bolt preload levels. These results may prove useful to appropriately design bolted joints to be used under specific stiffness and damping criteria, and therefore reducing the vibration response of the joint. [ABSTRACT FROM AUTHOR]

• Different proportions of polyurea were designed and their properties were compared. • The impact-resistant polyurea coating material was obtained through analysis. • Influence of polyurea coating on strength and peak strain of concrete was analyzed. • Failure modes of concrete and polyurea-coated concrete under impact were discussed. • Energy dissipation law of polyurea-coated concrete under impact load was studied. In order to effectively improve the impact resistance of concrete, polyurea elastomer coating with excellent impact resistance is obtained through formula design and performance testing, and it is coated on the end face of concrete specimen to prepare the polyurea-coated concrete composite specimen. The dynamic mechanical properties of the composite specimens are tested by using a large-diameter split Hopkinson pressure bar device. The variation laws of mechanical properties of polyurea-coated concrete under different strain rates and the influence of polyurea coating position on its dynamic properties and failure modes are analyzed, and the energy dissipation performance of polyurea-coated concrete is further discussed. The results shows that both concrete and polyurea-coated concrete exhibit obvious strain rate effects, that is, as the strain rate increases, the failure strength increases, and the fragments increase. When the strain rate is similar, the damage degree of concrete specimen coated with polyurea on front face (load-receiving face) is the lowest and the protection effect is the best. When polyurea is coated on the end face of concrete specimens, the peak strain is significantly increased and the brittleness is improved. With the increase of impact velocity, the peak value of dissipated energy of the composite specimens increases correspondingly, and its energy dissipation coefficient reaches the peak at about 0.45, which shows that as the incident energy peak increases, the dissipated energy peak does not increase indefinitely. [ABSTRACT FROM AUTHOR]

Osteochondral autologous transplantation is frequently used to repair small cartilage defects. Incongruence between the osteochondral graft surface and the adjacent cartilage leads to changed friction and contact pressure. The present study wanted to analyze the differences between intact and surgically treated cartilage surface in respect to contact pressure and frictional characteristic (dissipated energy). Six ovine carpometacarpal joints were used in the present study. Dissipated energy during instrumentally controlled joint movement as well as static contact pressure were measured in different cartilage states (intact, defect, deep-, flush-, high-implanted osteochondral graft and cartilage failure simulation on a high-implanted graft). The best contact area restoration was observed after the flush implantation. However, the dissipated energy measurements did not reveal an advantage of the flush implantation compared to the defect and deep-implanted graft states. The high-implanted graft was associated with a significant increase of the mean contact pressure and decrease of the contact area but the dissipated energy was on the level of intact cartilage in contrast to other treatments where the dissipated energy was significantly higher as in the intact state. However the cartilage failure simulation on the high-implanted graft showed the highest increase of the dissipated energy. [ABSTRACT FROM AUTHOR]

Abstract: We studied the segregation behavior of multi-size granular particles enclosed in a vertically vibrated container. In the experiment, we applied three kinds of 13X molecular sieve particles. The diameters of these particles are approximately 1:3:6 in the multi-size granular system. Under vibration, the system finally forms a stable hybrid convection mode, and the apparent tendency of the Brazilian nut (BN) effect occurs. The dissipated energy distribution model was introduced, in which the multi-size system was compared with the species competition system. We demonstrated that each kind of particle's top free surface area occupation percentage approximately equals its dissipated energy power percentage in the entire system. The results calculated according to the model well matched the experimental results. [Copyright &y& Elsevier]

This paper presents the development of a practical mortar fatigue model on the basis of the dissipated energy concept. A specially designed test setup was developed for characterization of mortar fatigue at meso-scale by means of dynamic shear rheometer. Test results showed that mortar fatigue models based on the dissipated energy concept can be developed for the purpose of life predictions under complicated loading conditions. The dissipated energy per cycle in the initial phase of fatigue tests is a practical indicator for fatigue life determination purposes than the total energy dissipated during a fatigue test. Since a mortar fatigue model based on the initial dissipated energy per cycle was adopted, effects of random stress and strain signals on mortar fatigue can be taken into account. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dissipated energy remains almost constant in significant portion of loading cycles at low strain tests. [•] The fatigue endurance limit value depends on the properties of hot mix asphalt mixture, test type and analysis method. [•] There is a transition point in semi log strain–Nf50 curve when the curve is regressed using the power law relation. [Copyright &y& Elsevier]

Highlights: [•] Extensive nanoindentation tests were conducted on both interfacial transition zone and bulk paste. [•] Grid indentation methodology was utilized to characterize nanomechanical properties of hydration phases. [•] Effect of high temperature on hydration products of lightweight concrete with fly ash and slag was determined. [•] High temperature damage on both interfacial transition zone and cement bulk were quantified. [•] Lightweight aggregate alleviates the high temperature damage on bulk cement paste. [Copyright &y& Elsevier]

Numerical and experimental studies of fatigue crack growth under both pure mode I and combined mode I and II were performed. A CT-like specimen with an additional hole for mixed-mode loading made from an Al-alloy D16CT1 was used. A 2D elastic-plastic FEM simulation of a growing fatigue crack allowed us to determine the value of the total plastic energy dissipation per cycle throughout the cyclic (reversed) plastic zone directly from the elastic-plastic stress and strain fields in the vicinity of a crack tip. According to the Klingbeil's theory, the total plastic energy dissipated ahead of a crack tip is related to the fatigue crack growth rate. To review this theory, experimentally observed fatigue crack growth rates were correlated to the computed energies for both straight and slant crack growth. Moreover, a comparison according to the conventional concept of an equivalent stress intensity factor is presented. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dissipated energy and maximum force were best correlated with apple bruise volume. [•] The soft variety ‘Freedom’ was characterized by the largest bruise surface area. [•] The hard variety ‘Rajka’ was characterized by the largest bruise depth. [•] 0.25ms−1 was the maximum safe velocity at which bruises did not develop. [Copyright &y& Elsevier]

The paper proposes an energy-based damage feature to detect the presence of earthquake-induced structural damage in instrumented buildings. The proposed feature is a function of the ratio between the hysteretic dissipated energy and the total dissipated energy. The main contribution of the paper consists in deriving an expression to estimate the dissipated energy ratio from a measured vibration response at a limited number of degrees of freedom. The proposed methodology is successfully implemented in the context of simulated multistory shear buildings and in a real instrumented building during two independent seismic events; one where the building did not sustain damage and the other were significant damage occurred. In both cases the proposed methodology performed the correct diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: The fatigue design of short fiber reinforced thermoplastics components for structural applications in the automotive industry requires an accurate knowledge of the numerous factors affecting the fatigue lifetime (process, loading type, environment, etc). This paper aims at describing a method based on thermal measurements (using an infrared camera) that will reduce substantially the characterization duration of the fatigue properties compare to classical methods. Recent publications illustrated the relevancy of using an energy based criterion to predict the fatigue properties. In this study, a simple way to get the cyclic dissipated energy from thermal measurements is suggested, usable for homogeneous and heterogeneous dissipation fields. A so-called heat build- up protocol is used to relate the cyclic stress amplitude to the cyclic dissipated energy. The parameters of an energy based criterion can be obtained within one day and using only one specimen, which is of course of huge interest to investigate quickly the influence of numerous factors on the fatigue behavior. In this study, this protocol is applied on one sample geometry, for one given orientation, and one humidity conditioning, and should be challenged by tests lead for several variations of first order parameters (fibers orientation, water uptake). [Copyright &y& Elsevier]

Background: Cartilage is a mechanically highly stressed tissue in the human body and an important part of synovial joints. The joint cartilage is lubricated by synovial fluid with hyaluronic acid (HA) as main component. However, in joints with osteoarthritis HA has a lower concentration and molecular weight compared to healthy joints. In recent years, the intra-articular injection of therapeutic HA lubricant, has become a popular therapy. The effect of HA application on the friction of a complete joint with physiological movement needs to be further determined., Methods: The aim of the present study was to evaluate the lubrication effect of the joint by three lubricants (NaCl, fetal calf serum (FCS) and HA) and their effect on the friction in nine complete ovine carpo-metacarpal joints. The joints were mounted on a material testing machine and a physiological movement with 10° rotation was simulated with ascending axial load (100 - 400 N). Specimens were tested native, with cartilage damage caused by drying out and relubricated. Dissipated energy (DE) as a measure of friction was recorded and compared., Results: Investigating the effect of axial load, we found significant differences in DE between all axial load steps (p < .001), however, only for the defect cartilage. Furthermore, we could document an increase in DE from native (Mean: 15.0 mJ/cycle, SD: 8.98) to cartilage damage (M: 74.4 mJ/cycle, SD: 79.02) and a decrease after relubrication to 23.6 mJ/cycle (SD: 18.47). Finally, we compared the DE values for NaCl, FCS and HA. The highest values were detected for NaCl (M Norm  = 16.4 mJ/cycle, SD: 19.14). HA achieved the lowest value (M Norm  = 4.3 mJ/cycle, SD: 4.31), although the gap to FCS (M Norm  = 5.1 mJ/cycle, SD: 7.07) was small., Conclusions: We were able to elucidate three effects in joints with cartilage damage. First, the friction in damaged joints increases significantly compared to native joints. Second, especially in damaged joints, the friction increases significantly more with increased axial load compared to native or relubricated joints. Third, lubricants can achieve an enormous decrease in friction. Comparing different lubricants, our results indicate the highest decrease in friction for HA., (© 2022. The Author(s).)

• Designed cold recycled mixes with 100% RAP using IDT and Air Voids at 50 gyrations. • 1% Cement stabilization improved fatigue life of cold mixes, followed by elastomers. • Superpave Gyratory Compaction at 50 gyrations used to determine OWC and OEC. • Tension-Compression test successfully evaluated fatigue performance of Cold mixes. • DER, 50% modulus drop, and peak of phase angle resulted in the same fatigue ranking. Cold recycling of pavements utilizes nearly 100% of the reclaimed asphalt pavement (RAP) for pavement rehabilitation. Due to the large amount of RAP, the cold recycled mixes would become prone to fatigue cracking, and hence evaluation of their fatigue performance becomes highly important. In this study, three cold recycled asphalt mixes were prepared using a regular cationic slow setting asphalt emulsions with hard base asphalt binder (CSS-1h) with and without Portland cement stabilization, and a polymer modified emulsion (CSS-1hp). The optimum emulsion and pre-mix water contents were determined using Superpave Gyratory compacted specimens through the mix design process by studying the air void levels and meeting minimum strength requirements. Fatigue properties of these three groups of mixes were then evaluated through a series of uniaxial cyclic tension–compression tests. The results were compared in terms of the modulus degradation, dissipated energy capacity, changes in phase angle, and number of cycles to failure, to determine the fatigue lives of the different mixes. The results indicated that adding 1% Portland cement to the cold recycled specimens significantly improved their fatigue performance as compared to the control scenario specimens prepared with regular CSS-1h emulsion. Using the polymer modified emulsion also led to a slightly improved fatigue resistance of the cold mix specimens as compared to the mixes prepared with regular emulsion. Furthermore, Multiple Stress Creep Recovery (MSCR) testing of the two residual emulsion binders indicated potential of improving the rutting resistance for the mixes prepared with the polymer modified emulsion. [ABSTRACT FROM AUTHOR]

• Triaxial cyclic tests under four confining pressures with different high temperature treatments were conducted. • Mechanical parameters of FC were more sensitive to temperature than to confining pressure. • Dissipated energy accounted for a large proportion under low confining pressure or high temperature. • The Crushable-foam yield criterion had good applicability to FC. Foamed concrete (FC) has been extensively used for its lightweight, good thermal insulation, and sound insulation properties. It has gained broad investigations in the past decades, but the data of triaxial cyclic compression tests are lacking. In this study, triaxial cyclic tests were conducted under different confining pressures (0 MPa, 0.3 MPa, 0.5 MPa, 0.8 MPa) with four temperature treatments (25 °C, 100 °C, 200 °C, 300 °C) to obtain the failure modes and stress-strain curves, analyze the compressive strength, residual strength, elastic modulus and brittleness index, explain the fracture mechanism and damage evolution of FC from the perspective of energy dissipation. Furthermore, the strength prediction model of FC was proposed and its yield criterion was verified. The results show that the damage pattern of FC was significantly influenced by confining pressure and the mechanical parameters were more sensitive to temperature. The energy density and damage increased linearly with the number of cycles, and the dissipated energy accounted for a large proportion under low confining pressure or high temperature. The Crushable-foam yield criterion had good applicability to FC, and thermal damage decreased the hydrostatic yield strength of FC. [ABSTRACT FROM AUTHOR]

• Effect of free water on fatigue life of concrete was clarified. • Effect of water and cyclic load on failure mode of concrete were discussed. • S–N curves of dry, saturated, and water-submerged concretes were determined. • Impact mechanism of free water on fatigue behavior of concrete was revealed. To clarify the effect of free water on the fatigue behaviour of concrete, dry, saturated, and water-submerged concretes were subjected to different stress levels of cyclic loads. The failure modes and S–N curves were determined. The evolution of fatigue deformation, the energy dissipation characteristics, and the impact mechanism were discussed. Water content was observed to affect the fatigue life of concrete. Owing to the interaction of free water, the fatigue life of concrete in saturated and water-submerged conditions reduced significantly compared to that of dry concrete. The compressive fatigue failure mode shifted from splitting failure in dry concrete to combined splitting and shearing failure in saturated concrete and shear failure in water-submerged concrete. The strain rate and dissipated energy of concrete in fatigue stage II increased with the water content and maximum stress level. The strain rate in stage II and the dissipated energy were logarithmically and linearly correlated with the fatigue life of concrete. [ABSTRACT FROM AUTHOR]