Penetration Resistance Research Articles

Effect of chloride ion corrosion on the microstructure of multiple interfaces of alkali-activated GGBS/FA based recycled concrete

In this paper, the resistance to chloride ion permeability of multiple interfaces in alkali-activated slag/fly ash (GGBS/FA) based full recycled concrete was investigated using the immersion method. In order to objectively and accurately reflect the microhardness and width of the interface transition zone (ITZ), box plots were used to process the measured point data. The results indicated that the microhardness of the interface was significantly lower than that of the matrix. The microhardness of the old aggregate interface (ITZOA-OM), the new aggregate interface (ITZOA-NM) and the new mortar interface (ITZOM-NM) all decreased to varying degrees with the extension of the immersion ages, but remained higher than that of the uneroded specimens. Chloride ions penetrated into ITZOA-OM and reacted with a large amount of enriched Ca (OH)2 to form an expansive composite salt (CaCl2.Ca(OH)2.H2O), which improved the microstructure of the ITZ, increased the microhardness and decreased the width of the ITZ. The dense structure of ITZOA-NM and ITZOM-NM inhibited the migration of chloride ions to a certain extent. leading to minimal changes in the width and microhardness of the ITZ. The micro mechanisms of chloride ion penetration resistance at the interfaces of alkali-activated GGBS/FA-based recycled concrete were investigated using BSE and EDS. More reaction products were generated at the interfaces after chloride ion erosion, and the newly generated substances continuously filled the microcracks, resulting in a more uniform bond at the interfaces. This contributed to the improvement of the microstructure and the resistance to chloride ion penetration of alkali-activated GGBS/FA based recycled concrete.

The Influence of Logging-Related Soil Disturbance on Pioneer Tree Regeneration in Mixed Temperate Forests.

The recovery of soil properties and the proper growth of natural tree regeneration are key elements for maintaining forest productivity after selective logging operations. This study was conducted on the soil properties and natural growth of two pioneer seedling species of alder and maple which were on skid trails in the mixed beech forests of northern Iran. To examine the long-term effects, we randomly selected six skid trails, with two replicates established for each of three time periods since last use (10, 20, and 30 years ago). Random plots 4 m × 10 m in size, three plots on each skid trail and six plots on areas without soil compaction (control), were selected. Measurements included the physical and chemical properties of the soil and the growth, and the architectural and qualitative characteristics of the seedlings. The results showed that all the soil properties of the 10- and 20-year-old skid trails were significantly different from the control area (except for the soil moisture in the 20-year-old skid trail). The 30-year-old skid trail showed values of other soil properties which were not significantly different from the control area, except for the amounts of organic matter and soil nitrogen, which was less than the control. The skid trails had a negative effect on all of the growth, qualitative, and architectural indices of seedlings. The characteristics of seedlings were related to soil characteristics and had the highest correlation with the soil penetration resistance (R-value from -0.41 to -0.63 for stem growth, p < 0.05; -0.57 to -0.90 for root growth, p < 0.01; and -0.76 to -0.86 for biomass, p < 0.01). The correlation coefficient between soil penetration resistance and the Dickson quality index of alder and maple seedlings was, respectively, -0.74 and -0.72, p < 0.01. The negative effect of soil compaction on root growth (-27.69% for alder seedlings and -28.08% for maple seedlings) was greater than on stem growth (-24.11% for alder seedlings and -16.27% for maple seedlings). The amount of growth, qualitative, and architectural indices of alder seedlings were higher than that of maple seedlings. Although alder is a better choice as compared to maple seedling in the initial year, the results of our study show that it is recommended to plant both alder and maple on skid trails after logging operations.

Penetration resistance of honeycomb ceramic matrix composites with filler material

The major purpose of this study is to analyze the resistance of honeycomb ceramic matrix composites to penetration and to explore the effect of the performance characteristics of the filler materials on this capability. We used alumina ceramics, polyurea, quartz sand powder, and boron carbide powder to manufacture composite materials, and conducted impact tests and numerical simulations on them. The simulation results of Abaqus were found to be very consistent with the test results. The results demonstrate that the polyurea coating and filler materials may effectively improve the anti-penetration penetration performance of the composites, and different filler materials have varying energy absorption effects. Extended research on composites was carried out utilizing experimentally validated numerical models with filler materials comprising silicon carbide, aluminum nitride, and silicon nitride. After a comparative analysis of the simulation results of different composites, compared to quartz sand composites, the energy absorption efficiency of boron carbide composites increased by 12.03 %, silicon carbide composites increased by 14.63 %, aluminum nitride composites increased by 15.16 %, and silicon nitride composites increased by 18.29 %. Among the relevant materials in this study, there exists an optimal value of the stress wave impedance difference between the matrix material and the filler material. Honeycomb ceramic matrix composites with an ideal combination of stress wave impedance differences can considerably increase the anti-penetration efficiency of the composites.

Penetration resistance Mechanism and damage characteristics of polyurea-coated B4C ceramic plates

Penetration resistance Mechanism and damage characteristics of polyurea-coated B₄C ceramic plates

Controlled Chemical‐Patterning of Textile to Accelerate Anti‐Gravity Water Flow

AbstractBio‐inspired unidirectional flow of tiny aqueous droplets across the fibrous substrate paved the way for the emergence of various advanced materials. In the past, textiles decorated with noncontact‐based wettability‐patterns enabled unidirectional water flow—without flooding the top surface by the transferred water. However, such approaches mostly suffer from a low (≈0.176 µL mm−2 s−1) flow rate and are likely to delay the overall liquid ejection process. Here, a chemically reactive coating capable of tailoring water wettability (121.3° ± 2.4° to 153.3° ± 1.8°) is introduced on commercially available textiles to develop chemically modulated wettability‐pattern for achieving a rapid (2.57 ± 0.28 µL mm−2 s−1) flow rate of water against the gravity with an ability to roll the accumulated liquids on the top surface. The spatially selected and controlled chemical modification with hydrophilic and hydrophobic small molecules through a 1, 4‐conjugate addition reaction yielded a 3D channel with a customized wettability gradient. The pinning and depinning of invaded water through such chemically decorated channels enabled unidirectional and fast penetration of liquid, where the water penetration resistance largely depends on the water penetration direction and dimension of the chemically modulated channels.

Evaluating installation of suction caisson in sand via accounting for soil seepage-deformation coupled process

Suction-assisted installation is one of the special features that distinguishes the suction caisson from other offshore foundations. Suction control during installation can be challenging, as it involves highly coupled processes between seepage flow and seabed soil deformations, including excessive soil deformation and plug formation under strong seepage actions that lead to early termination of the installation, as well as a seepage flow-induced reduction in caisson penetration resistance. However, existing methods for evaluating suction caisson installation are primarily based on pure seepage analysis while disregarding the above-coupled processes. This paper proposes an approach to evaluate suction caisson installation in sand by explicitly accounting for seepage-deformation coupling. For this purpose, pore pressure-deformation coupled finite element analyses are performed to investigate soil failure mechanism and evolving caisson penetration resistance subjected to suction. These analyses result in novel rules for assessing critical suction upon the rapid growth of soil deformation and describing the degradation of caisson penetration resistance. The latter two propositions lead to a new calculation method for determining the required suction for caisson installation. The performance of the calculation method is evaluated against field tests and centrifuge tests to illustrate the usefulness of considering coupled soil deformation-seepage process in designing caisson installation.

Sand mining deteriorates soil fertility and farming livelihoods around Accra, Ghana

Urbanization in Sub-Saharan Africa requires vast quantities of sand to meet infrastructural demands. In Accra, Ghana, sand mining occurs predominantly on farmlands at the city’s periphery. We selected three study communities to assess the effects of sand mining on agriculture using interviews with local farmers and soil analyses of mined and unmined fields. The results underscore the profound repercussions of sand mining on farmers, characterized by substantial agricultural land loss, the destruction of food crops, and the absence of compensation payments or land reclamation. The study further reveals a significant decline in soil fertility of mined fields compared to unmined fields as evidenced by reduced levels of carbon (C, by 6.3 g kg-1) and macronutrients (nitrogen (N, by 0.6 g kg-1), phosphorus (P, 12.7 mg kg-1), potassium (K, 77 mg kg-1) and magnesium (Mg, 88 mg kg-1)), and an increase in soil compaction (bulk density by 0.13 g cm-3 and penetration resistance by 0.11 MPa). Soil texture and pH were altered and sodium (Na, by 16 mg kg-1) and soil moisture (by 4%) increased. On a communal level, sand mining adversely affected water availability, road infrastructure, and the health of residents. The study fills research gaps on the effects of sand mining on agricultural productivity, soil fertility and livelihoods, emphasizing the urgent need for effective regulation, law enforcement and collaboration as well as compensation and land reclamation mechanisms to limit the adverse impacts of sand mining on ecosystem services. Further, the use of more sustainable building materials should be fostered to reduce the demand for sand in Ghana.

Chloride transport in alkali-activated materials influenced by different reaction products: a review

Alkali-activated materials (AAMs) are regarded as a substitute for Portland cement. They have high chloride resistance and a low carbon dioxide footprint. The aim of this review is to provide a multi-scale perspective to understand material–product–microstructure–property relationships in terms of the chloride binding behaviour of AAMs. The physical and chemical chloride stability of different reaction products is summarised from nanostructure, to microstructure to macro properties. An analysis of studies in the literature gives an overview of recent progress in chloride transport in AAMs influenced by different reaction products. Results show that a higher calcium/silicon, aluminium/silicon molar ratios and alkali content increase the formation of amorphous phases, leading to a denser microstructure and lower chloride penetration in AAMs. Higher magnesium oxide and aluminium oxide contents result in increased formation of hydrotalcite. The enhanced physical and chemical absorption of chloride by hydrotalcite leads to higher resistance of chloride penetration in AAMs. Investigation of increasing chloride resistance could potentially focus on increasing gel and hydrotalcite formation.

A Review of Gene-Property Mapping of Cementitious Materials from the Perspective of Material Genome Approach.

As an important gelling material, cementitious materials are widely used in civil engineering construction. Currently, research on these materials is conducted using experimental and numerical image processing methods, which enable the observation and analysis of structural changes and mechanical properties. These methods are instrumental in designing cementitious materials with specific performance criteria, despite their resource-intensive nature. The material genome approach represents a novel trend in material research and development. The establishment of a material gene database facilitates the rapid and precise determination of relationships between characteristic genes and performance, enabling the bidirectional design of cementitious materials' composition and properties. This paper reviews the characteristic genes of cementitious materials from nano-, micro-, and macro-scale perspectives. It summarizes the characteristic genes, analyzes expression parameters at various scales, and concludes regarding their relationship to mechanical properties. On the nanoscale, calcium hydrated silicate (C-S-H) is identified as the most important characteristic gene, with the calcium-silicon ratio being the key parameter describing its structure. On the microscale, the pore structure and bubble system are key characteristics, with parameters such as porosity, pore size distribution, pore shape, air content, and the bubble spacing coefficient directly affecting properties like frost resistance, permeability, and compressive strength. On the macroscale, the aggregate emerges as the most important component of cementitious materials. Its shape, angularity, surface texture (grain), crushing index, and water absorption are the main characteristics influencing properties such as chloride ion penetration resistance, viscosity, fluidity, and strength. By analyzing and mapping the relationship between these genes and properties across different scales, this paper offers new insights and establishes a reference framework for the targeted design of cementitious material properties.

Mediterranean beech forests: Thinning and ground-based skidding are found to alter microarthropod biodiversity with no effect on litter decomposition rate

Despite the high ecological value of Mediterranean beech forests, very little is known about the implications of forest operations on soil microarthropod biodiversity and litter decomposition rate. There is also no information concerning the amount of time needed for disturbed forest soil to recover and return to the pre-harvesting conditions. Silvicultural treatments are scheduled about every ten to fifteen years, without taking into account the amount of time necessary for recovery. The purpose of this study was to determine this information. The study started by selecting three study sites located along the Italian Apennine, each including a chronosequence of three forest parcels: one harvested in 2021, one harvested in 2012, and a control parcel which had not been harvested within the last forty years. In the harvested parcels we investigated skid trails which are classified as disturbed, and soil not affected by the passage of a machine which is classified as undisturbed. Thus in each study area there were five experimental treatments including the control area. The soil physico-chemical properties were assessed for each treatment. These included bulk density, penetration resistance, shear resistance, organic matter content, and soil microarthropod biodiversity which was assessed by the QBS-ar index (Soil Biological Quality based on microarthropods, a qualitative index measuring the quality of soil according to the biodiversity of the microarthropod community). We further established a litter decomposition experiment, using teabags as reference material, to check the differences among treatments in litter decomposition rates. We used linear mixed-effects models to investigate the effects of the experimental treatment on the physico-chemical and biological features, and relationships among QBS-ar index and soil physico-chemical features. We analysed the effects of the experimental treatment on the litter decomposition rate using generalised linear-mixed effects models. A significant effect caused by machine passage was found in the recently harvested parcels on soil penetration resistance (∼+70 % comparing to the control), shear resistance (∼+35 %), and QBS-ar index (-25 %). Effects of machine passage on soil bulk density and organic matter content were not significant. All the investigated variables in the skid trails returned to values similar to those recorded in the control after ten years. We did not find effects of any soil physico-chemical features on QBS-ar index. Finally, no effect of the experimental treatment was found on the litter decomposition rate, suggesting that a stronger magnitude of soil disturbance is needed to affect this complex biogeochemical process. Although the initial impact was highly significant, it was found that a 10-year period is sufficient for recovering the investigated soil features in the upper soil layer. This was observed in Mediterranean beech forests when forest operations were done with low-weight machines and a limited number of machine passes on the skid trails. Thus, it can be concluded that planning another operation 10–15 years after the previous thinning, as is currently done, remains in line with the time needed for the forest soil to recover.

The influence of projectile impact velocity and target characteristics on the terminal ballistics parameters of small-caliber projectile

The study examines the results of numerical simulations of the penetration of a 7,62mm x 63, AP, M2 projectile through a target. Model validation involved a numerical simulation of 7,62mm x 63, AP, M2 projectile penetration through an AA5083H116 target, for which experimental results were available in the literature. The results of the numerical simulation were used for regression analysis - to calibrate the Recht-Ipson model for the given projectile. Furthermore, penetration analyses of 7,62mm x 63, AP, M2 projectiles through various target materials were performed at consistent projectile velocities and mesh sizes. As expected, bainitic steels exhibited the highest resilience, demonstrating that increased material hardness and tensile strength correlate with enhanced projectile penetration resistance.

Evaluating Use of Hydraulic Modified Sulfur Powder in Concrete Pavements: Laboratory Testing and Field Application

This study comprehensively evaluates the field applicability of hydraulic modified sulfur (HMS) as a concrete additive. We assessed the microstructural characteristics, mechanical properties, and durability performance of HMS at various replacement ratios in a laboratory setting. In addition, a field study was conducted by removing an existing conventional concrete pavement measuring (6000 × 12,000 × 70 mm, W × L × T) and overlaying it with HMS concrete. The experimental results revealed that HMS enhanced the mechanical and durability performance when used as a cement replacement at rates below 9%. These results satisfied the quality control standards and performance criteria specified in the Korean standard specification for cement-concrete pavements. The comparative analysis revealed that HMS concrete outperformed conventional concrete mixtures by 62.6% in sulfuric acid penetration depth, 14.8% in compressive strength retention after sulfuric acid immersion, and 53.1% in chloride-ion penetration resistance. Furthermore, no anomalies were detected during the 3-month follow-up period.

Anti-penetration properties of negative Poisson’s ratio honeycomb sandwich structure filled with foam

The ballistic responses of negative Poisson’s ratio honeycomb sandwich structures filled with aluminum foam are investigated using numerical simulation method. The residual velocity of the projectile, the energy absorption, and the failure forms of the sandwich structures are systematically analyzed. The influence of the impact position and incidence angle of the projectile, wall thickness, and concave angle of honeycomb, as well as the thickness of the front and back sheets of the structure on the penetration resistance is discussed. The results show that the foam-filled honeycomb sandwich structure has a better penetration resistance than the foam core sandwich structure with the same areal density, and the penetration resistance of the foam-filled honeycomb sandwich structure can be improved by designing its geometric parameters.

Wheat cover crop has minimal effect on physical soil properties in the North Carolina Piedmont

AbstractEnvironmental awareness about soil and water conservation in agroecosystems has shifted behaviors toward favoring conservation practices in agricultural management. Interest in conservation tillage and cover cropping has increased, but some regions encounter major challenges with adjusting management to accommodate these practices while optimizing crop production. In an Ultisol in the North Carolina Piedmont, a long‐term corn (Zea mays) and soybean (Glycine max) rotation with tillage intensities ranging from no‐till to moldboard plowing in a randomized complete block design was used to assess changes in physical soil properties after introducing wheat (Triticum aestivum) as a winter cover crop. Cover crop biomass was measured along with volumetric water content (VWC) and bulk density (BD) at 0–15 cm, water retention (WR), water‐stable aggregation (WSA), and soil organic carbon (SOC) at 0–7.5 cm, and penetration resistance (PR) at 0–45 cm. No differences in VWC or WR could be solely attributed to cover cropping, but no‐till with cover cropping had the highest macroporosity where there was no vehicle traffic. Vehicle traffic had a stronger effect on soil compaction (BD and PR) than cover cropping regardless of tillage. Conservation tillage increased WSA and SOC when compared to plow tillage, but three seasons of a wheat cover crop did not significantly change these properties, possibly because wheat produced low biomass each year (750–1900 kg ha−1). Wheat had minimal effect on physical soil properties in the short term, and potential for improvement with long‐term optimal cover crop management in this region requires further assessment.

A random elastoplastic framework of relationships between CBR and Young’s modulus for coarse-grained soils

The material quality indicator most commonly used for the quality of road materials is the California Bearing Ratio test (CBR). In addition, the CBR test provides a value commonly used to correlate with the resilient modulus (used in the design and analysis of pavement) due to its cost-effectiveness. This test measures soil resistance to penetration by a punch and compares it with the pressure measured in a standard material at the same penetration (2.5 mm or 5 mm). However, this test lacks physical explanations regarding mechanical behavior because the CBR value only compares soil penetration resistance with the pressure measured in a standard material. Another issue arises from the scattered results obtained from both equations and tests, highlighting the need for variability analysis of the CBR test to assess the effect of the different geotechnical variables on the CBR value. For this purpose, simulations using FEM (Finite Element Method) considering random soil parameters were performed for the CBR test. These FEMs included a linear elastic model and two failure criteria (Mohr–Coulomb and Drucker-Prager with a cap) and were prepared for granular soils. The evaluation shows that the increase or decrease in the CBR value is a function of the elastic modulus, yield stress, and friction angle. Moreover, the simulations expand the knowledge of the shearing mechanisms, generated stresses, displacement fields, and load sharing when the CBR test is made. From these results, a physical explanation of test results can be done. FEM simulations showed stress zones in conditions of elastic, compression, and shear behavior. These zones can explain the importance of elastic modulus, yielding stress, and friction angle in the CBR value. From numerical results, a new equation was proposed and compared with practical equations proposed by international standards and other sources to estimate the probability of underestimated values CBR according to the correlations used.

Combined use of chemical dust suppressant and herbaceous plants for tailings dust control.

Tailings dust can negatively affect the surrounding environment and communities because the tailings are vulnerable to wind erosion. In this study, the effects of halides (sodium chloride [NaCl], calcium chloride [CaCl2], and magnesium chloride hexahydrate [MgCl2·6H2O]), and polymer materials (polyacrylamide [PAM], polyvinyl alcohol [PVA], and calcium lignosulfonate [LS]) were investigated for the stabilization of tailings for dust control. Erect milkvetch (Astragalus adsurgens), ryegrass (Lolium perenne L.), and Bermuda grass (Cynodon dactylon) were planted in the tailings and sprayed with chemical dust suppressants. The growth status of the plants and their effects on the mechanical properties of tailings were also studied. The results show that the weight loss of tailings was stabilized by halides and polymers, and decreased with increasing concentration and spraying amount of the solutions. The penetration resistance of tailings stabilized by halides and polymers increased with increasing concentration and spraying amount of the solutions. Among the halides and polymers tested, the use of CaCl2 and PAM resulted in the best control of tailings dust, respectively. CaCl2 solution reduces the adaptability of plants and therefore makes it difficult for grass seeds to germinate normally. PAM solutions are beneficial for the development of herbaceous plants. Among the three herbaceous species, ryegrass exhibited the best degree of development and was more suitable for growth in the tailings. The ryegrass plants planted in the tailings sprayed with PAM grew the best, and the root-soil complex that formed increased the shear strength of the tailings.

FOREST HARVESTING: HOW MACHINE TRAFFIC CAN AFFECT SOIL COMPACTION VARIABILITY

The forestry sector has seen an increase in wood demand in recent years, requiring greater mechanization and sustainability in forestry operations, operational excellence, and productivity of stands. The effect of harvesting machine traffic on the soil alters its physical properties, causing degradation, soil compaction, and reducing the volumes of wood produced by commercial forests. Thus, the objective of the present study was to evaluate the spatial variability of soil physical attributes after harvesting and skidding operations, carried out by a harvester and forwarder respectively, in a commercial eucalyptus plantation. The study was conducted in two areas in the municipalities of Itanagra-BA and Entre Rios-BA. Samples were collected in three layers (0-0.20 m; 0.20–0.40 m; 0.40–0.60 m) and the following items were evaluated: total porosity, bulk density, and soil penetration resistance. Operations performed by the harvester and forwarder altered soil resistance, with a greater effect on sandy loam soils, decreasing their density and porosity. Regarding the number of forwarder passes, the seventh pass generated the peak resistance, altering soil recovery capacity, causing additional compaction. Operational planning, to reduce the effects of compaction in areas most susceptible to physical soil degradation, is essential in the forestry area, especially when moisture values are high, a factor that favors soil compaction and reduces stand productivity.

Tillage, crop residue management and nitrogen application impacts on soil properties under maize–wheat (Zea mays–Triticum aestivum) cropping system

Tillage intensity, crop residue retention and nitrogen application can significantly impact the soil properties and crop productivity. We studied the effect of tillage (deep tillage [DT] vs. shallow tillage [ST]) in main plots and residue management viz. conventional tillage without residue (CT-R), conventional tillage with residue (CT+R), minimum tillage without residue (MT-R) and minimum tillage with residue (MT+R) in sub plots and fertilizer-N at 75, 100 and 125% N (viz. N75, N100 and N125) in sub-sub plots. Field treatments were established in maize-wheat (Zea mays-Triticum aestivum) cropping system during 2016-2019 at two different locations in north-western India and were arranged in split-split plot design. The soil penetration resistance was significantly lower under deep tillage (3.4 to 3.7%) as compared to shallow tillage. CT+R recorded lowest penetration resistance as compared to other tillage and residue combinations but other soil properties like OC, available NPK, soil aggregation, infiltration rate did not differ significantly. The addition of crop residue both under minimum and conventional tillage significantly increased the soil microorganism count and dehydrogenase enzyme activity at both locations. CT-R recorded lowest microorganism count and dehydrogenase enzyme activity. The available soil nitrogen, microorganism count and dehydrogenase enzyme activity significantly increased with increasing nitrogen doses at both locations and were highest under 125% N level as compared to 75% and 100% levels. In both crops, the grain yield was not significantly affected by tillage and crop residue combinations while the different levels of nitrogen fertilizer significantly affected the grain yield. From soil health and sustainability point of view, CT+R treatment with 100% recommended dose of nitrogen in maize-wheat crop rotation seemed beneficial.

An alternative approach to protect micro-cracked reinforced concrete under a marine environment

This research aimed to establish prevention guidelines and mitigate the effects of chloride penetration in micro-cracked concrete by enhancing the quality of additive materials or fly ash and employing galvanic cathodic protection to guard against steel corrosion. The effects of micro-crack deterioration in reinforced concrete beams on the corrosion of reinforcing steel bars were investigated. Fly ash (FA) was replaced ordinary Portland cement (OPC) at rates of 0 %, 15 %, 30 %, and 45 % by weight of binder, with a water-to-binder (W/B) ratio of 0.45. Prevention measures included removing large particle sizes of the fly ash, and grinding to achieve high fineness, ensuring that particles retained on a sieve No.325 were less than 5 %. The test results showed that increasing the replacement of OPC with FA improved the chloride penetration resistance of the concrete, with lower detected chloride content compared to OPC concrete, and reduced the weight loss of the reinforcing steel bars. Additionally, the improvement of fly ash (IPF concrete) reduced the electric current to less than 20 mA, whereas the control concrete (PC) exhibited electric currents of about 80–100 mA. Another effective method for protecting against steel corrosion is the use of galvanic cathodic protection (GCP) in concrete, which can help reduce the electric current to 10 mA. Guidelines and preventive measures are suggested to ensure that structures can withstand environmental over time, maintaining their reliability and safety throughout their service life.

Hydromechanical modelling of the influence of water saturation on the penetration performance of concrete target

The objective of the present paper is to study numerically the hydro-mechanical behaviour of concrete targets subjected to a rigid projectile, with special attention to the influence of water saturation. An elastoplastic model, encompassing two primary plastic mechanisms (shear and pore collapse), is improved to capture the influence of water saturation. The adopted model is implemented in the finite element code Abaqus/Explicit and validated by simulating two dynamic compression tests at the material point level and two penetration tests at the structure level. Not only a strong influence of water saturation on both volumetric and deviatoric behaviours of concrete is observed at material point level, but also the time-evolutions of projectile velocity, projectile deceleration and penetration depth in concrete targets are also satisfactorily reproduced by the numerical simulations. After that, a series of parametric studies are performed to understand the influence of water saturation on the penetration performance of concrete. It is found that with the presence of pore water, penetration resistance of concrete increases with decreasing water saturation, indicating a higher projectile deceleration and lower penetration depth obtained in saturated targets. Numerical modelling and analysis will enhance our understanding of the vulnerability of concrete infrastructures subjected to near-field detonations or impacts.