Who is Ken Day?

Ken describes himself as "an evangelistic concrete technologist" and says this means that concrete technology is his religion and he wanders around the world preaching it to anyone who will listen. Actually Ken is more specialised than that. His expertise is mainly in mix design, quality control and specification - although he has been a consulting structural engineer, a university lecturer, a precast and prestressed concrete producer, and a general investigator and legal expert witness of defective concrete.

Ken hopes to be remembered for originating two basic concepts:

•  Multigrade, multivariable cusum quality control

•  Specific surface mix design

It has been said that there is nothing new under the sun and neither of these concepts arose out of thin air, but both are things which did not work well until Ken started working on them and which it took literally decades to convince others to use.

Cusum (cumulative sum analysis) was first applied to concrete by RMC (the company, as distinct from the industry) in England in the early 1970s but graphs were neither multigrade nor multivariable. Ken was drawing non-cusum multivariable quality control charts in 1953 and was already looking into cusum when the more advanced RMC development came to his attention and was incorporated. UK cusum is still not multivariable but does now use a type of multigrading which is different to Ken's (and in his opinion substantially less powerful).

Specific surface mix design had been conceived decades earlier and the original basis was heavily promoted in 1954 by Newman and Teychenne but did not work properly until Ken modified the calculation basis of specific surface in the late 1950s.

What Ken will probably be remembered for is being the leader in the whole field of statistical quality control for concrete and in computerising mix design and QC in his Conad program. Articles were published on the former in the 1950s and computerisation followed in the late 1970s.

Many specifiers of concrete will certainly remember him for his strongly worded and very public attacks on traditional specifications. One unfortunate individual was referred to as "a member of the flat earth society" in a letter to an editor in the 1960s. It is amazing that the USA is only now, 50 years later, coming to accept what was always obvious to Ken. One strongly held view still not generally accepted is that cash penalties for minor specification infringements are essential for justice.

In recent years Ken has come to be regarded as less of a rebel than in his early days.

He has been elected as a Fellow of the Institution of Engineers (Australia), the American Concrete Institute, the UK Institute of Concrete Technology, and, in 2002, an Honorary Member of the Concrete Institute of Australia.

In 2006 he was awarded a lifetime achievement award for his developments in concrete QC by Canmet/ACI.

And in 2011 the Richard Gaynor Award for services to NRMCA (National RMC Assn of USA).

In 2011 he was also persuaded to visit Penang to advise on problems with casting units for the 2nd Penang Bridge and to give a high profile presentation on QC to a Convention in Delhi, India.