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Mr Samuel Boys

Mr Samuel Boys

Highly Commended Winner 2015
The Strength Development of GGBS Concrete With Metakaolin

Research Abstract

The use of supplementary cementitious materials (SCM) can reduce the incorporated CO2 content of concrete by replacing a proportion of the ordinary Portland cement (OPC) content, as well as producing concrete with enhanced properties. Ground, granulated blast-furnace slag (GGBS) is an SCM produced as a by-product in the manufacture of iron, and is known to produce high strength and durability concretes. However, GGBS gain strength more slowly than OPC, although given time can produce a higher long-term strength concrete. This currently precludes GGBS from use in fast-track applications such as pre-cast facilities and short construction programmes.


Metakaolin is another SCM, produced by heat-treatment of china clay, which has recently seen interest due to its rapid early strength gain. Used in lower replacement ratios than GGBS, some studies have shown that it can produce beneficial effects when used in combination with other SCM such as GGBS.


This dissertation seeks to clarify the relationship between the metakaolin replacement ratio and the compressive strength gain of GGBS concrete in order to determine whether metakaolin can be used to produce a GGBS concrete with early strength gain comparable to that of OPC concrete.

Winner's Bios

Mr Samuel Boys

Leeds Beckett University, UK

Samuel ran a successful small landscaping and building firm with a partner for 10 years, before enrolling to study BSc Construction Management at Leeds Beckett University in 2011. A successful 18-month placement with GMI Construction followed, along with a myriad of prizes: The Shepherd Construction Prize for best overall student, the CIOB prize for Advanced Construction Technology, the CIOB QEII scholarship, and the CIOB prize for Outstanding Graduate. After graduating with a first class honours degree in 2015, Samuel now works as a site manager for GMI Construction, where he is part of a small team overseeing the construction of a new-build luxury hotel in central Leeds. 


Judge's comments

“It is an excellent dissertation based on laboratory-based research justified by an extensive and appropriate literature review. Rather than rerunning old experiments, the research offers up-to-date testing which would not look out of place in a commercial laboratory. It was especially refreshing to see such a clear reflection on the research limitations which is unusual for an undergraduate dissertation. The dissertation is well written and structured with extraordinary clarity.”