Concrete and Earthquake Engineering Research Group

Department of Civil & Structural Engineering

Dr Abdulaziz Alsaif

PhD Student


Department of Civil and Structural Engineering
Sir Frederick Mappin Building
Mappin Street,
S1 3JD


Abdulaziz completed a five-year B.S. degree in Civil Engineering with major in Structural Engineering in Saudi Arabia at King Saud University, and finished a master degree in Structural Engineering in the United States at University of California Davis. After finishing the B.S. degree, he worked in King Saud University as a Teaching Assistant, and also, worked for The Centre of Excellence for Concrete Research and Testing, as a Quality Assurance and Construction Site Inspector. After obtaining the master degree, he worked as a project manager for a non-profit organization in Saudi Arabia for a year. He has started and succefully completed his PhD at The University of Sheffield. The topic of his PhD thesis was ‘Rubberised Concrete with Recycled Tyre Steel Fibres’ 

Recent activities and achievements

Project title: Rubberised Concrete with Recycled Tyre Steel Fibres

Objectives: This research program on rubberised concrete aimed at developing highly deformable elements to be used in seismic applications. 

Tasks and methodology:

An initial pilot study (aiming at developing highly deformable elements to be used in seismic applications) was performed to assess the compressive behaviour and investigate the effect of RTSF on unconfined and confined RuC cylinders.  Zero and 40% of waste tyre rubber were used as partial volume replacement of both fine and coarse aggregates.  Various dosages of RTSF were examined (0, 20 and 40 kg/m3) and different confinement levels using Aramid Fibre Reinforced Polymers (AFRP) jackets (0, 2 and 4 layers) were applied. Results show that adding RTSF to the confined RuC mixes helped very little.

A second pilot study was carried out to examine the potential of Steel Fibre Reinforced Rubberised Concrete (SFRRuC) for use in flexible pavements, floors and slabs on grade. A total of 10 batches were prepared using cylinders, cubes and prisms cast with different ratios of waste tyre rubber as partial volume replacement of both fine and coarse aggregates (0, 20, 40 and 60%). Various dosages of MSF and/or RTSF (0, 20 and 40 kg/m3) were used. The fresh properties namely, the slump, density and air content were assessed for each mix.  The uniaxial compressive strength and the stress vs. strain behaviour were examined. The free shrinkage, autogenous and dry, were recorded for each prism and then the flexural behaviour was investigated by performing three-point flexural tests. Result show that the MSF and/or RTSF reinforcement has considerably enhanced the flexural behaviour of RuC.

Future parametric study on the fresh properties, mechanical performance, transport mechanism and pore-structure related properties and long-term performance of selected SFRRuC mixes will be investigated to confirm its potential use in flexible pavements.  

Expected results: 

  • An optimum mix design for the rubberised concrete with recycled tyre steel fibres which satisfies the standards of the concrete fresh properties. 
  • Concrete cylinders that exhibit high energy dissipation, ductility, toughness and compressive strength. 
  • Flexible concrete prisms that show significant level of enhancement of the ductility, toughness and flexural behaviours.
  • The addition of rubber in concrete would have a detrimental effects on the concrete long term performance.  However, the presence of MSF and/or RTSF would most likely mitigate the negative effects caused by the rubber inclusion.

Supervisor: Prof. Kypros Pilakoutas

Research project(s)


Innovative Use of all Tyre Components in Concrete
Anagennisi: Innovative Use of all Tyre Components in Concrete An estimated one billion tyres are discarded each year. Post-Consumer tyre arisings for EU countries (2010) are 3.4M tonnes per year. At the moment nearly 50% of all recycled tyres/components still end up as fuel, in low grade applications or in...