This thesis identified key mix design variables that influence the mechanical
properties and behaviour of shockpads and developed a mechanical model to
describe this behaviour.
This investigation was undertaken to address the lack of scientific understanding of
shockpad layers used in synthetic sports pitches. Shockpads play a crucial role in the
player and ball interaction properties of synthetic pitches. However, the current poor
state of knowledge regarding shockpad mix design effects and the implications for
site practice during construction was developed through constructor experience and
basic testing. This lack of comprehensive knowledge was reflected in the barelyexistent
standards for design specification and testing requirements stipulated by
sporting governing bodies at the time of this project inception. Further scientific
investigation of the effects of shockpad mix design on mechanical properties and
behaviour was required to develop guidelines to optimise shockpad design,
construction and testing and also to build more knowledge on sport surface
behaviour due to growing interest among the industry and other stakeholders such as
governing bodies and sport shoe manufacturers for example.
A method to construct small-scale cast in-situ shockpads in the laboratory was
developed to produce reliable and repeatable samples for investigation, including a
benchmark shockpad and shockpads with carefully controlled mix design variations.
Shockpad thickness, binder content, binder type, rubber size, rubber size distribution
and bulk density were varied through a range of appropriate values in the laboratory
constructed shockpads. Shockpads and shockpad-carpet systems (using water based
and 3'1 generation carpets) were subjected to Berlin Artificial Athlete and 2.25 kg
Clegg Hammer impacts to measure player-surface interaction properties and vertical
hockey ball impacts to measure ball interaction properties. Tensile measurements and
cyclic fatigue testing were used to determine shockpad durability. Impact testing was
repeated on shockpads and shockpad-carpet systems with thickness variations to determine shockpad behaviour using a force plate. Behaviour measurements were
used to develop a mechanical model to describe shockpad behaviour. (Continues...).
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.