© 2018 Elsevier Ltd. All rights reserved. Development of Ultra-High Performance Concrete against Blasts: From Materials to Structures presents a detailed overview of UHPC development and its related applications in an era of rising terrorism around the world. Chapters present case studies on the novel development of the new generation of UHPC with nano additives. Field blast test results on reinforced concrete columns made with UHPC and UHPC filled double-skin tubes columns are also presented and compiled, as is the residual load-carrying capacities of blast-damaged structural members and the exceptional performance of novel UHPC materials that illustrate its potential in protective structural design. As a notable representative, ultra-high performance concrete (UHPC) has now been widely investigated by government agencies and universities. UHPC inherits many positive aspects of ultra-high strength concrete (UHSC) and is equipped with improved ductility as a result of fiber addition. These features make it an ideal construction material for bridge decks, storage halls, thin-wall shell structures, and other infrastructure because of its protective properties against seismic, impact and blast loads.
Meng, Q, Wu, C, Su, Y, Li, J, Liu, J & Pang, J 2019, 'A study of steel wire mesh reinforced high performance geopolymer concrete slabs under blast loading', Journal of Cleaner Production, vol. 210, pp. 1150-1163.View/Download from: Publisher's site
In this study, a novel green construction material, high performance alkali-activated geopolymer concrete is introduced. Both numerically and experimentally investigations were conducted on a new type of structural slabs made of steel wire mesh reinforced geopolymer concrete against close-in ground surface explosion. Steel rebar reinforced conventional concrete slabs are also studied to compare the results. The experimental investigation was conducted to study the slab damage mechanism. It is found that the steel wire mesh reinforced geopolymer concrete slab showed less damage and fragmentation under 50 kg Trinitrotoluene (TNT) blast load within 3 m, 5 m and 7 m distances as compared to the C30 concrete slab. Numerical analysis was then conducted to further investigate the slab dynamic responses. Combining the steel wire mesh reinforcement with geopolymer concrete can help increase the blast resistance capacity leading to promising and environmental friendly structural protective design.
Liu, J, Wu, C, Li, J, Fang, J, Su, Y & Shao, R 2019, 'Ceramic balls protected ultra-high performance concrete structure against projectile impact-A numerical study', INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, vol. 125, pp. 143-162.View/Download from: Publisher's site
Shao, R, Wu, C, Su, Y, Liu, Z, Liu, J, Chen, G & Xu, S 2019, 'Experimental and numerical investigations of penetration resistance of ultra-high strength concrete protected with ceramic balls subjected to projectile impact', Ceramics International, vol. 45, no. 6, pp. 7961-7975.View/Download from: Publisher's site
© 2019 Elsevier Ltd and Techna Group S.r.l. Ceramic materials characterized by high hardness, high inherent strength, low density and excellent dimensional stability have been extensively applied in the design of high-performance and lightweight protective structures to resist the high-speed projectile impact. In order to study the anti-penetration capability of ceramic balls protected ultra-high strength concrete (CB-UHSC), high-speed projectile impact tests were conducted at striking velocities of 545 m/s, 679 m/s, and 809 m/s to investigate the impact performance of ceramic balls, projectiles, and the protected UHSC. The experimental results indicated the effectiveness and economy of ceramic balls in resisting the high-speed projectile impact. Numerical studies were then conducted to reproduce the projectile penetration process within CB-UHSC targets with the assistance of LS-DYNA. Based on the validated numerical models, impact resistance and ballistic deviation of projectiles, as well as the energy evolution between projectiles and targets, were further investigated to comprehensively understand the impact performance of this newly designed protective structure under projectile penetration.
Liu, J, Wu, C, Li, C, Dong, W, Su, Y, Li, J, Cui, N, Zeng, F, Dai, L, Meng, Q & Pang, J 2019, 'Blast testing of high performance geopolymer composite walls reinforced with steel wire mesh and aluminium foam', Construction and Building Materials, vol. 197, pp. 533-547.View/Download from: Publisher's site
© 2018 Elsevier Ltd Two blast tests were conducted to study the blast resistance of high performance geopolymer composite walls reinforced with steel wire mesh (SWM) and aluminium foam (AF). Conventional reinforced concrete (CRC) walls were also tested as control specimens. In total seven walls were tested under different blast loading conditions. The first blast test was conducted on one 2260 mm × 2260 mm × 150 mm SWM reinforced, one 2260 mm × 1000 mm × 150 mm SWM reinforced and one 2260 mm × 1000 mm × 150 mm combined SWM and AF reinforced high performance geopolymer composite walls under 50 kg TNT explosives at a standoff distance of 2.3 m. The second blast test was conducted on one 2260 mm × 2260 mm × 150 mm SWM reinforced and one 2260 mm × 2260 mm × 150 mm combined SWM and AF reinforced high performance geopolymer composite walls under 100 kg TNT explosives on the ground at the same standoff distance. Blast tests were also performed on two 2260 mm × 2260 mm × 150 mm CRC walls under such two designed explosions to compare their behaviours with reinforced high performance geopolymer composite walls. LVDT (linear variable differential transformer) devices were used to record the deflection histories and pressure sensors were used to measure the airblast pressure histories. The testing results indicated that the combined SWM and AF reinforced high performance geopolymer composite walls had a better blast resistance than the CRC walls, and the SWM reinforced high performance geopolymer composite wall was superior to both.
Shao, R, Wu, C, Liu, Z, Su, Y, Liu, J, Chen, G & Xu, S 2018, 'Penetration resistance of ultra-high-strength concrete protected with layers of high-toughness and lightweight energy absorption materials', Composite Structures, vol. 185, pp. 807-820.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd Aluminium foam has advantages of excellent shock absorption, cyclic utilization, and lightweight. Ultra-high-molecular-weight polyethylene (UHMWPE) fibre has a low density, a high specific strength, a high modulus and a great capability in energy absorption. Steel wire mesh has high toughness and elongation properties and a good effect on energy absorption. In the present study, UHMWPE fibre, steel wire mesh and aluminium foam were used to protect ultra-high-strength concrete (UHSC) targets to resist DT300 high-strength alloy-steel projectile penetration with striking velocities from 550 m/s to 800 m/s. High-speed impact tests on normal-strength concrete (NSC) targets were also conducted for comparison. Testing results including the failure mode, depth of penetration (DOP), crater dimensions and damage area of protected concrete targets, indicate that the new composite material protective cover has an outstanding performance in the shock wave absorption, especially in reducing the crack propagation and debris spatter of protected UHSC targets, as well as increasing the deviation angles of projectile terminal ballistic trajectories. It is a successful demonstration of anti-penetration properties research for new concrete composite structures.
Liu, J, Wu, C, Li, J, Su, Y & Chen, X 2018, 'Numerical investigation of reactive powder concrete reinforced with steel wire mesh against high-velocity projectile penetration', CONSTRUCTION AND BUILDING MATERIALS, vol. 166, pp. 855-872.View/Download from: UTS OPUS or Publisher's site
Liang, X, Wu, C, Su, Y, Chen, Z & Li, Z 2018, 'Development of ultra-high performance concrete with high fire resistance', CONSTRUCTION AND BUILDING MATERIALS, vol. 179, pp. 400-412.View/Download from: UTS OPUS or Publisher's site
Liu, J, Wu, C, Su, Y, Li, J, Shao, R, Chen, G & Liu, Z 2018, 'Experimental and numerical studies of ultra-high performance concrete targets against high-velocity projectile impacts', Engineering Structures, vol. 173, pp. 166-179.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd Ultra-high performance concrete (UHPC) which is known for high strength, high toughness, excellent ductility and good energy absorption capacity can be adopted as an ideal material in the impact resistant design of structures. In the present study, impact responses of UHPC targets with 3 vol-% ultra-high molecular weight polyethylene (UHMWPE) fibres and UHPC targets with 3 vol-% steel fibres are experimentally investigated subjected to high-velocity projectile penetration, and plain concrete targets under the same loading scenarios are also tested as control specimens for comparative purpose. In addition, numerical studies are conducted to simulate the projectile penetration process into UHPC targets with the assistance of a computer program LS-DYNA. The numerical results in terms of the depth of penetration (DOP) and crater diameter as well as projectile abrasions and damages are compared with the experimental results. Moreover, DOPs of these two types of UHPC targets obtained from tests are compared with the previously proposed empirical model.
Wu, P, Liu, Z, Wu, C, Zhang, H, Xu, S & Su, Y 2017, 'Influence of Steel Fibre on Dynamic Compressive Properties of Ultra-High Performance Concrete', Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/Journal of Tianjin University Science and Technology, vol. 50, no. 9, pp. 939-945.View/Download from: UTS OPUS or Publisher's site
© 2017, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved. The dynamic and static compressive experiments on ultra-high performance concrete(UHPC)were carried out, including five sets of specimens with different mixtures, by utilizing the 75 mm split Hopkinson pressure bar (SHPB) system and the YAW-3000 electro-hydraulic servo testing machine, respectively. The effects of types and volume ratios of steel fibers on dynamic compressive strength were analyzed in detail. The dynamic increase factors of UHPC for different mixtures were calculated and the diagram of dynamic increase factors was further obtained. The results indicate that the dynamic compressive strength and peak strain of the UHPC increase significantly with the increase of strain rates; the types and volume ratios of steel fibers have great effect on the dynamic properties of the UHPC but little effect on the dynamic increase factor; a better improvement effect of fibers with greater length-diameter ratios on the dynamic compressive strength of the UHPC was also clearly observed.
Li, J, Wu, C, Hao, H & Su, Y 2017, 'Experimental and numerical study on steel wire mesh reinforced concrete slab under contact explosion', MATERIALS & DESIGN, vol. 116, pp. 77-91.View/Download from: UTS OPUS or Publisher's site
Su, Y, Li, J, Wu, C, Wu, P, Tao, M & Li, X 2017, 'Mesoscale study of steel fibre-reinforced ultra-high performance concrete under static and dynamic loads', Materials and Design, vol. 116, pp. 340-351.View/Download from: UTS OPUS or Publisher's site
© 2016 Elsevier Ltd In this paper, a three-dimensional numerical model to study the static and dynamic behaviour of ultra-high performance steel fibre reinforced concrete is developed. Ultra-high performance steel fibre reinforced concrete is assumed to be a two-phase model consisting of concrete matrix and steel fibres. The concrete matrix is modelled with homogeneous material and the straight round steel fibres are assumed to be dispersed with random locations and orientations in the matrix. The interfacial transition zone (ITZ) effect is studied based on the single fibre pull-out tests, and parameters describing the fibre-matrix one dimensional bond-slip behaviour are obtained and discussed based on both experimental and theoretical results. After the three-dimensional model is validated with static split tensile tests, split Hopkinson pressure bar (SHPB) split tensile tests are numerically modelled and the stress-time history is interpreted in the mesoscale level. The proposed model qualitatively and quantitatively predicts the material static and dynamic behaviours, and also gives insights on the fibre reinforcement effect in the concrete matrix.
Su, Y, Wu, C, Li, J, Li, Z-X & Li, W 2017, 'Development of novel ultra-high performance concrete: From material to structure', CONSTRUCTION AND BUILDING MATERIALS, vol. 135, pp. 517-528.View/Download from: UTS OPUS or Publisher's site
Li, J, Wu, C, Hao, H, Su, Y & Li, ZX 2017, 'A study of concrete slabs with steel wire mesh reinforcement under close-in explosive loads', International Journal of Impact Engineering, vol. 110, pp. 242-254.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd.Structural responses and damages under blast loading environments are critical to structural and personnel safety. The blast scenarios involving close-in detonations are attracting increasingly more attentions over the last few decades due to the rising of terrorism. Under close-in detonations, structural elements tend to fail in a brittle mode including shear, concrete crater and spall. In such loading scenarios, the structural designated loading capacity which is usually based on flexural deformation assumption is not fully developed. To provide high-level structural protection, high performance concretes with varying fibre additions are now widely investigated and used in blast resistance designs. In the present study, field blast tests results on reinforced concrete slabs under close-in detonations are presented. Performances of slabs made of normal strength concrete and steel fibre reinforced concrete are compared and discussed. Besides conventional steel rebar reinforcement, new reinforcement scheme i.e. hybrid steel wire mesh-micro steel fibre reinforcement is investigated through the laboratory static tests and field blast tests. Furthermore, a numerical study based on Multi-Material ALE and Lagrangian algorithm is carried out to further investigate the field tests' phenomenon.
Liu, J, Wu, C, Li, J, Su, Y, Shao, R, Liu, Z & Chen, G 2017, 'Experimental and numerical study of reactive powder concrete reinforced with steel wire mesh against projectile penetration', International Journal of Impact Engineering, vol. 109, pp. 131-149.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd This paper presents experimental and numerical studies on impact resistance of reactive powder concrete (RPC) targets reinforced with 44-layer steel wire meshes. Steel ogive-nosed projectiles with an average mass of 330 g and striking velocities ranging from 550 m/s to 800 m/s were launched against the cylindrical RPC targets with 750 mm diameter and 700 mm thickness. The impact responses observed in the tests, including depth of penetration (DOP), crater diameter and volume loss, were investigated and discussed, which indicates an effective impact resistance of steel wire mesh reinforced RPC in comparison with the previous studies on ultra-high performance based cement composites (UHPCC) with additions of fibres and basalt aggregates. Numerical studies based on validated material and element models are also conducted to simulate the impact responses of reinforced RPC targets against high-velocity proj ectile penetration in explicit hydro-code LS-DYNA. The impact responses, especially for the DOP, are well predicted by using the numerical models. Moreover, further investigation based on the verified numerical models is discussed in the present paper to explore the influence of mechanical and physical properties of steel wire mesh reinforcement on the resistance of projectile penetration.
Xu, S, Wu, C, Liu, Z, Han, K, Su, Y, Zhao, J & Li, J 2017, 'Experimental investigation of seismic behavior of ultra-high performance steel fiber reinforced concrete columns', Engineering Structures, vol. 152, pp. 129-148.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd This paper presents an experimental study on seismic behavior of ultra-high performance steel fiber reinforced concrete (UHPSFRC) columns. Based on a series of cyclic loading tests on 14 UHPSFRC specimens subjected to combined static axial loading and cyclic lateral loading, the investig ation and analysis have been carried out on crack status, failure modes, hysteretic loops, skeleton curves, strength and stiffness degradation, energy dissipation capacity and ductility of UHPSFRC columns. The influence of stirrup spacing, type of stirrup, axial compression ratio and shear span ratio on the seismic performance of UHPSFRC columns was also investigated in details. The experiment results show that three typical failure modes are observed, i.e., flexural, flexural-shear and shear failure mode. The existence of steel fiber could prevent the cracked concrete from spalling efficiently and delay the bulking of longitudinal reinforcement further. It noteworthy that the limit plastic drift ratio of all columns changes from 0.036 to 0.061, indicating that the UHPSFRC columns represent a good ductility which is obviously different from the conventional high strength concrete columns that exhibit much more brittleness with the increase of strength.
Su, Y, Li, J, Wu, C, Wu, P & Li, Z-X 2016, 'Influences of nano-particles on dynamic strength of ultra-high performance concrete', COMPOSITES PART B-ENGINEERING, vol. 91, pp. 595-609.View/Download from: Publisher's site
Li, J, Wu, C, Hao, H, Wang, Z & Su, Y 2016, 'Experimental investigation of ultra-high performance concrete slabs under contact explosions', INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, vol. 93, pp. 62-75.View/Download from: UTS OPUS or Publisher's site
Xu, J, Wu, C, Xiang, H, Su, Y, Li, Z-X, Fang, Q, Hao, H, Liu, Z, Zhang, Y & Li, J 2016, 'Behaviour of ultra high performance fibre reinforced concrete columns subjected to blast loading', ENGINEERING STRUCTURES, vol. 118, pp. 97-107.View/Download from: Publisher's site
Li, J, Wu, C, Hao, H & Su, Y 2015, 'Investigation of ultra-high performance concrete under static and blast loads', International Journal of Protective Structures, vol. 6, no. 2, pp. 217-234.View/Download from: UTS OPUS or Publisher's site
Conventional concrete works as an important construction material. However, conventional concrete is known to be brittle and prone to tensile failure and cracks. To overcome such defects and improve the dynamic performance of concrete against extreme loading conditions, concrete with different additions and formulae have been developed. In a recent study, to develop ultra-high performance concrete (UHPC) material with better strength and crack control ability, super fine aggregates with high pozzolanic effect were mixed into the steel fibre reinforced concrete instead of the traditional graded coarse aggregates. Furthermore, to achieve high early age strength, nanoscale additives which can accelerate the hydration process of the ordinary Portland cement were also introduced into the concrete composite. A series of uniaxial compression and four-point bending tests had been performed in the laboratory to get the material properties of this innovative concrete material. Great improvement of the concrete uniaxial compressive strength and flexural tensile strength was observed. Field blast tests were carried out on columns made of this UHPC material. Superior blast resistance performance was observed. In the current study, based on the available test data, numerical models are developed and numerical simulations are carried out. The simulation results are found to comply well with the experimental results.
Su, Y, Wu, C & Oehlers, DJ 2013, 'Modelling of the concrete compressive failure mechanism', Australian Journal of Structural Engineering // the Institution of Engineers, Australia, vol. 14, no. 3, pp. 243-257.View/Download from: UTS OPUS or Publisher's site
There has been an extensive amount of research into determining the compressive stress-strain properties of concrete for design. Difficulty has arisen in quantifying the softening or descending stress-strain relationship as it has been found to depend on the size and shape of the specimen being tested as well as on the confinement and eccentricity of compressive load applied to the specimen. This difficulty has restricted the development of design rules for reinforced concrete members not only for strength but also for ductility particularly for confined members. In this paper, a meso-scale model, which divides concrete into a three phase composite material consisting of the mortar matrix, aggregate and interfacial transition zone, is used to explain and quantify the softening mechanism of concrete specimens. It is shown that this meso-scale model can both simulate the cracking patterns and deformations which are seen to occur in concrete while softening and also quantify and explain the effects of size, shape, confinement and eccentricity of load. This realistic simulation of the softening mechanism should allow a better understanding and quantification of the compressive failure mechanism of concrete which should lead to the development of better design rules particularly for confined concrete. © Institution of Engineers Australia, 2013.
Su, Y, Wu, C & Griffth, MC 2011, 'Modelling of the bond-slip behavior in FRP reinforced masonry', CONSTRUCTION AND BUILDING MATERIALS, vol. 25, no. 1, pp. 328-334.View/Download from: UTS OPUS or Publisher's site
Su, Y, Wu, C & Griffith, M 2008, 'Mitigation of blast effects on aluminum foam protected masonry walls', Transactions of Tianjin University, vol. 14, no. SUPPL., pp. 558-562.View/Download from: Publisher's site
Terrorist attacks using improvised explosive devices (IED) can result in unreinforced masonry (URM) wall collapse. Protecting URM wall from IED attack is very complicated. An effective solution to mitigate blast effects on URM wall is to retrofit URM walls with metallic foam sheets to absorb blast energy. However, mitigation of blast effects on metallic foam protected URM walls is currently in their infancy in the world. In this paper, numerical models are used to simulate the performance of aluminum foam protected URM walls subjected to blast loads. A distinctive model, in which mortar and brick units of masonry are discritized individually, is used to model the performance of masonry and the contact between the masonry and steel face-sheet of aluminum foam is modelled using the interface element model. The aluminum foam is modelled by a nonlinear elastoplastic material model. The material models for masonry, aluminum foam and interface are then coded into a finite element program LS-DYNA3D to perform the numerical calculations of response and damage of aluminum foam protected URM walls under airblast loads. Discussion is made on the effectiveness of the aluminum foam protected system for URM wall against blast loads.
Su, Y, Wu, C-Q & Grifflh, M 2008, 'NUMERICAL SIMULATION OF BOND-SLIP MODELS BETWEEN FRP AND MASONRY IN PULL TESTS', PROCEEDINGS OF THE TENTH INTERNATIONAL SYMPOSIUM ON STRUCTURAL ENGINEERING FOR YOUNG EXPERTS, VOLS I AND II, 10th International Symposium on Structural Engineering for Young Experts, SCIENCE PRESS BEIJING, Hunan Univ, Changsha, PEOPLES R CHINA, pp. 530-536.