Dr Dan Bompa


Lecturer in Civil and Structural Engineering
PhD CEng MIStructE EurIng
+44 (0)1483 683390
25 AA 02
Book a meeting here: https://bit.ly/dvbompa

Academic and research departments

Department of Civil and Environmental Engineering.

Biography

Research projects

My teaching

Courses I teach on

Undergraduate

Postgraduate taught

My publications

Publications

D.V Bompa, B Xu, A.Y Elghazouli (2021)Constitutive modelling and mechanical properties of cementitious composites incorporating recycled vinyl banner plastics, In: Construction & Building Materials275122159 Elsevier Ltd
This paper describes an experimental study, which has been lacking to date, into the mechanical properties of cementitious composites incorporating granules and fibres from recycled Reinforced PVC (RPVC) banners. A detailed account of over 140 tests on cylindrical, cubic and prismatic samples tested in compression and flexure, with up to 20% replacement of mineral aggregates, is given. Based on the test results, the uniaxial properties of selected recycled materials are examined in conjunction with a detailed characterisation of the RPVC granule size and geometry. Experimental measurements using digital image correlation techniques enable a detailed interpretation of the full constitutive response in terms of compression stress-strain behaviour and flexural stress-crack opening curves, as well as key mechanical parameters such as strength, elastic modulus and fracture energy. It is shown that the mechanical properties decrease proportionally with the amount of RPVC. For each 10% increment of volumetric replacement of mineral aggregates, the compressive strength is halved whilst the flexural strength is reduced by about 30% compared to their conventional counterparts. The reduction in strength is counterbalanced by an improved ductility represented by a favourable post-peak response in compression and an enhanced flexural softening and post-cracking performance. Smaller particles, with a relatively long acicular or triangular geometry, exhibited better behaviour as these acted as fibres with improved bond properties in comparison with intermediate and large size granules. The test results and observations enable the definition of a series of expressions to determine the mechanical properties of cementitious materials incorporating RPVC and other waste plastics. These expressions are then used as a basis for an analytical model for assessing the compressive and tensile stress-strain response of such materials. Validations carried out against the tests undertaken in this study, as well as from previous investigations, indicate that the proposed expressions and the developed constitutive model offer reliable representations for practical application.
D.V Bompa, A. Y. Elghazouli (2020)Compressive behaviour of fired-clay brick and lime mortar masonry components in dry and wet conditions, In: Materials and Structures53(3) Springer
This paper examines the fundamentalmechanical properties of masonry elements incorpo-rating fired-clay bricks and hydraulic lime mortarsunder ambient-dry and wet conditions, correspondingto 48 h submersion in water. In addition to comple-mentary material characterisation assessments, twotypes of specimens are tested: cylindrical cores incompression, and wall elements in compression.Overall, a detailed account of more than 50 tests isgiven. Apart from conventional measurements, the useof digital image correlation techniques enables adetailed assessment of the influence of moisture on theconstitutive response, confinement effects andmechanical properties of masonry components. Theuniaxial compressive strengths of wet brick elementsand brick–mortar components, resulting from tests oncylindrical cores with height-to-depth ratios of aroundtwo, are shown to be 13–18% lower than those inambient-dry conditions. The tests also show thatenhanced confinement levels in brick units mobilise67–92% higher strengths than in the correspondingunconfined cylinders. Moreover, experimental obser-vations indicate that the presence of significantconfinement reduces the influence of moisture on themechanical properties as a function of the brick andmortar joint thickness and their relative stiffness. As aresult, the failure of wet masonry walls in compressionis found to be only marginally lower than those inambient-dry conditions. Based on the test results, theinfluence of moisture on the constitutive response andmechanical properties of masonry components isdiscussed, and considerations for practical applicationare highlighted
Dan Bompa, A.Y. Elghazouli (2019)Behaviour of confined rubberised concrete members under combined loading conditions, In: Magazine of Concrete Researchpp. 1-55 ICE Publishing
This paper presents an experimental study into the fundamental response of reinforced concrete members, which incorporate rubber particles obtained from recycled tyres, subjected to combined axial–bending loading conditions. Tests on confined circular members with and without internal hoops or external fibre-reinforced polymer (FRP) sheets are described. The results show that the rubber particles enhance the confinement level activated, with confined/unconfined strength and deformation capacity ratios at least twice those of conventional concrete members. The hoop-confined members provided with 30% rubber developed a typical reinforced concrete behaviour, with relatively limited deformation capacity in comparison with FRP-confined members. The external confinement substantially enhanced the ultimate rotation of members incorporating 30% rubber, with ductility factors reaching up to ten for relatively small eccentricity levels. An increase in rubber content to 60% had a detrimental effect on the axial capacity, but increased the ultimate rotation up to twice in comparison with members with 30% rubber. Based on the test results, a design-oriented constitutive model for FRP-confined concrete and a variable confinement procedure for assessing the strength interaction of circular sections are proposed. The suggested procedures capture, in a realistic manner, the influence of rubber content on the strength and deformation characteristics of confined members.
B. Xu, D.V Bompa, A.Y. Elghazouli (2020)Cyclic stress–strain rate-dependent response of rubberised concrete, In: Construction and Building Materials254119253 Elsevier
This paper presents an experimental investigation into the constitutive response of rubberised concrete materials under monotonic and cyclic compression. After describing the test specimens and experimental arrangement, a detailed account of the stress–strain response of rubberised concrete materials, as well as their reference high strength conventional concrete, is given. The volumetric rubber content is varied between 0 and 40% of both fine and coarse aggregates. Both monotonic and cyclic loading conditions are considered for comparison, and three strain rate levels, simulating static, moderate and severe seismic action, are examined. The increase in rubber content is shown to have a detrimental effect on the stiffness and strength, as expected. However, with the increase in rubber content, rubberised concrete materials are shown to exhibit improved compressive recovery under cyclic loading, coupled with a higher energy accumulation rate, enhanced inter-cycle stability and lower inter-cycle degradation. It is also shown that the increase in strain rate, from static to severe seismic, leads to a notable increase in the stiffness and strength, with these enhancements becoming less significant with the increase in rubber content. Based on the results and observations, expressions for determining the unloading stiffness and residual strain, as a function of rubber content and strain rate, are proposed within the ranges considered. The suggested relationships enable the characterisation of rubberised concrete materials within widely used cyclic constitutive models.
C. Ţibea, Dan V. Bompa (2020)Ultimate shear response of ultra-high-performance steel fibre-reinforced concrete elements, In: Archives of Civil and Mechanical Engineering20(2) Elsevier
This paper examines the experimental performance of ultra-high-performance steel fibre-reinforced concrete (UHPSFRC) beams subjected to loads at relatively low shear span-to-depth ratios. The results and observations from six tests provide a detailed insight into the ultimate response including shear strength and failure mode of structural elements incorporating various fibre contents. The test results showed that a higher fibre content results in an increase in ultimate capacity and some enhancement in terms of ductility. Detailed nonlinear numerical validations and sensitivity studies were also undertaken in order to obtain further insights into the response of UHPSFRC beams, with particular focus on the influence of the shear span-to-depth ratio, fibre content and flexural reinforcement ratio. The parametric investigations showed that a reduction in shear span-to-depth ratio results in an increase in the member capacity, whilst a reduction in the flexural reinforcement ratio produces a lower ultimate capacity and a relatively more flexible response. The test results combined with those from numerical simulations enabled the development of a series of design expressions to estimate the shear strength of such members. Validations were performed against the results in this paper, as well as against a collated database from previous experimental studies.
B. Xu, D.V Bompa, A.Y. Elghazouli, A.M. Ruiz-Teran, P.J. Stafford (2019)Numerical assessment of reinforced concrete members incorporating recycled rubber materials, In: Engineering Structures204110017 Elsevier
This paper is concerned with the inelastic behaviour of reinforced concrete beam-column members incorporating rubber from recycled tyres. Detailed three-dimensional nonlinear numerical simulations and parametric assessments are carried out using finite element analysis in conjunction with concrete damage plasticity models. Validations of the adopted nonlinear finite element procedures are carried out against experimental results from a series of tests involving conventional and rubberised concrete flexural members and varying levels of axial load. The influence of key parameters, such as the concrete strength, rubber content, reinforcement ratio and level of axial load, on the performance of such members, is then examined in detail. Based on the results, analytical models are proposed for predicting the strength interaction as well as the ductility characteristics of rubberised reinforced concrete members. The findings permit the development of design expressions for determining the ultimate rotation capacity of members, using a rotation ductility parameter, or through a suggested plastic hinge assessment procedure. The proposed expressions are shown to offer reliable estimates of strength and ductility of reinforced rubberised concrete members, which are suitable for practical application and implementation in codified guidance.
D.V Bompa, A.Y. Elghazouli (2019)Stress–strain response and practical design expressions for FRP-confined recycled tyre rubber concrete, In: Construction and Building Materials237117633 Elsevier
This paper presents an experimental programme on the response of fibre reinforced polymer (FRP) confined circular rubberised concrete (RuC) members in compression. After describing the constituent materials and testing arrangement, a detailed account of the complete stress–strain response of FRP-confined high strength conventional concrete materials (CCM) and RuC in uniaxial compression is provided. The parameters directly investigated through experimental assessment are the rubber content, namely 30% and 60% by volume of both fine and coarse aggregates, and the number of confinement layers which varies from 0 to 4. Experimental observations indicate that the confined compressive strength typically increases in a largely proportional manner with the unconfined compressive strength, whilst the confined axial strain at ultimate tends to increase with the rubber content. Confined-to-unconfined strength ratios above 9 and confined ultimate strain-to-unconfined crushing strain ratios above 40, are obtained for concrete with 60% rubber and four layers of confinement. These values are higher by factors of about 3.2 and 4.5 in comparison to the conventional reference concrete, respectively. The test results and observations enable the development of a series of design expressions to estimate the stress–strain response of circular RuC specimens passively confined with FRP sheets, with due account for the influence of rubber content. Validations performed against the material tests carried out in this paper, as well as those from previous studies on RuC and CCM with FRP confinement, indicate that the proposed expressions offer reliable predictions of the mechanical properties of FRP-confined members.

Additional publications