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...).
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