Ken's Papers and Powerpoints:

Click on these section headings to jump to the section in question:

Mix Design

Quality Control

Specification

Other Papers (presentations)

Recent Papers

Recent Publications

FIB 2008 (Holland)

Singapore OWICS 2009 address

Delhi March 2011 address

Tasmanian Sept 2011 address

 

Papers: Mix Design[Back on top]

Ken's work on mix design started immediately he left university in 1952. His first employer, Unit Construction Co., had a subsidiary Pierhead Ltd that was producing precast, prestressed flooring joists using aluminous cement concrete of zero slump (actually earth-dry, we called it "minus 4"slump", required to attain a minimum 7,500psi at 18hrs to permit a 24hr production cycle without heating, even in the London winter.

Ken looked at the then-available techniques of Road Note 4, ACI and D.A.Stewart's excellent little book "High Quality Concrete"(Spon 1951) without finding a numerical explanation for his experimental results showing the crucial importance of sand fineness. It was not until Newman and Teychenne's work on specific surface in 1954 that the solution was found.

Still the theory did not quite match the test data and it was not until Ken moved to Humes Ltd. in Melbourne, Australia in 1955 that he evolved his "modified specific surface"figures to correct this. The figures were published in 1959 and later confirmed during a laboratory investigation at the University of NSW (Sydney, Australia) in 1960/61.(see screencam on explanation/justification for modified figures)

A further development was necessary to produce a really workable mix design system. This was to take account of cement and entrained air contents. It was seen that more cement or more entrained air had the same effect on concrete as more or finer sand. So a new parameter he christened the "MSF"(Mix Suitability Factor) came into being combining the effects of aggregate surface area, cement content, and entrained air on the cohesion of a mix.

But, while additional cement increased water demand, as did more or finer sand, entrained air reduced water demand. So a second parameter was necessary he called "EWF"(Equivalent Water Factor) combining the effects of aggregate surface area and cement but subtracting the effect of entrained air.

So now a complete mix design system for one coarse and one fine aggregate, cement and water existed. A strength parameter was also needed but that differed from cement to cement and could best be obtained by using an initially conservative assumption and feeding back early test results. This system was used for many years to design mixes for use in many parts of S.E.Asia "over the telephone"on receipt of a faxed sand grading.

  • Mathematical Methods of Proportioning Aggregates, Concrete and Constructional Engineering, February 1959
    ( View Paper )

    • Giving factors for modified specific surface. (still using almost identical figures today)

  • Discussion by K. Day of paper Specific Surface of Aggregates Applied to Mix Proportioning by B.J. Singh, ACI Journal Sept 1959.
    ( View Paper )

    • Expands on basis of modified specific surface and gives examples of use on several projects in Australia.

  • An Analysis of Concrete Pumpability
    ( View Paper )

    • Pumpability Symposium circa 1980

    Still quite relevant

  • Marginal Sands
    ( View Paper )

    • Paper presented at ACI San Antonio Convention, March 1987

    A still relevant analysis of the limits of usability of less than ideal sands and a method of designing concrete with them using my SS/MSF concepts "at that time using a Hewlett Packard HP41cv calculator fitted with a custom-made Mixtune Module designed by myself.

  • Computer Control of Concrete Proportions
    ( View Paper )

    • Concrete International, December 1996

  • JUST-IN-TIME MIX DESIGN
    ( View Paper ) ( View Powerpoint )

    • ACI Convention, Cancun, Mexico, Dec 2002.

    A paper suggesting that each truck of concrete should have its contents individually proportioned.

  • MIX DESIGN COMPETITION

    • In 2003 Hanley Wood, publisher of US magazine Pit and Quarry, in conjunction with ARI (Aggregate Research Institute) organised a mix design competition. Ken Day took part in this and the story is worth reading. It took more than a year to obtain any detail from them. Here is my 5 page report and a spreadsheet analysing the 48 other entries.

    (view Report and Data Sheets) ( View Spreadsheet )

PAPERS: Quality Control[Back on top]

The earlier papers are of historical rather than technical interest and are provided to show the time scale of developments.

  • Discussion at Mix Design and QC Symposium (I)
    London, 1954, ( View Paper )

    • Shows appreciation of effect of sand grading on water/strength, also of coarse aggregate shape on sand requirement.

  • Discussion at Mix Design and QC Symposium (II)
    London, 1954, ( View Paper )

    • Shows origination of multi-variable control chart, also advocates Std Deviation rather than Coefficient of Variation (STILL not accepted by several ACI committees!)

  • Quality control in prestressed concrete production
    ( View Paper )

    • By OJ Masterman, Magazine of Concrete Research, August 1958

    Paper by my first employer, describes control system I set up 1952-54. Interesting innovations were multi-variable control charts, bridge gauge for elastic modulus measurement (I conceived and actually made it!) and siphon can for W/C ratio (again my idea but taken up by Dr Orchard at CACA). Note low SD of 307psi (2MPa) on 9000psi concrete.

  • Statistical Quality Control of Concrete and Concrete Products
    ( View Paper )

    • A series of 3 articles in Commonwealth Engineer Dec 1958, Jan & Feb 1959

    Shewhart multivariable control charts, statistical analysis before computers, even before calculators! Strength specification, advocation of cash penalty basis. (STILL not acceptable but I still believe it to be desirable).

  • Economical Control of Concrete Quality
    ( View Paper )

    • Australian Civil Engineering, May 1969

    A comprehensive proposal and specifications for both the concrete and the control organisation for the use of an external laboratory and field staff to control concrete quality.(This was prior to the introduction of the cusum technique).

  • Quality Control of 55MPa Concrete for Collins Place Project, Melbourne. Australia
    ( View Paper )

    • A paper given at the 1979 ACI Milwaukee Convention but not published in Concrete International until March 1981. Covers introduction of cusum technique and detailed comparison of two testing laboratories testing same concrete with different results.

  • Quality Control of Concrete: Philosophy and Implementation
    ( View Paper )

    • Hong Kong University Symposium, October 1980

    A wide-ranging paper including details of the Australian scene at that time. Emphasises the difference between QC and acceptance testing.

  • Concrete Quality Control by Cusum Analysis
    ( View Paper ) ( View Cusum Screencam )

    • ERMCO 83 British RMC Assn., London May 1983

    Compares Quality Control, Quality Assurance and Acceptance testing. Covers prediction by adding average gain rather than percentage and presents my (manually plotted) control system.

  • Selecting a Concrete Testing Laboratory
    ( View Paper )

    • Memo to Melbourne clients circa 1980-83 (as a consultant, after ceasing to operate a laboratory myself). Includes comparative data on several laboratories over a period of three years.

  • Bad Concrete or Bad Testing?
    ( View Paper )

    • ACI San Diego Convention, November 1989

    Puts forward the view that individual test results are unreliable but the properly analysed pattern of test data is very reliable (unfortunately the slides of graphs are not available)

  • Computerized Concrete QC using spreadsheets and cusum graphs
    ( View Paper )

    • The cover, contents and introduction pages only are provided to ACI Compilation 13, published in 1991 but reprinting a series of 10 articles appearing in Concrete International in the late 1980s. These publications cover the use of Lotus 123 spreadsheets for concrete QC

  • Equivalent Slump
    ( View Paper ) ( View Powerpoint )

    • RILEM/University of Paisley Conference, Glasgow, June 1996

    Important to realise that "slumps ain't slumps" unless they are corrected for time and temperature.

  • Concrete Quality Control: Past, Present and Future
    ( View Paper ) ( View Powerpoint )

    • Concrete Institute of Australia Biennial, July 2002.

    Covers the evolution of QC techniques over the past 50 years, showing that some countries (especially USA) are many years behind others

PAPERS: Specification[Back on top]

NB. Several of the papers under QC also deal with specification.

For the last 50 years I have been kicking against the way specification writers have inhibited the development of improved control techniques by denying producers any advantage through reduced variability, better mix design,or as I put it, knowing or caring anything about concrete technology!

Here is a small selection:

  • The Specification of Concrete
    ( View Paper )

    • Constructional Review, July 1961

    General philosophy, comparison of percent defective spec with cash penalty with then current Australian spec (CA2-1958) also examines possible use of 1% and 0.1% limits. All with detailed mathematical examination and graphical presentation

  • Recommended Specification (circa 1969)
    ( View Paper )

    • An intermediate stage of weaning specifiers from minimum cement contents, interference with mix designs, excessive sampling rates and an unfair and unreliable rejection basis. This was produced after the period in which I owned a testing laboratory. It was just coming into significant use in Melbourne when a recession brought an end to all major projects in Melbourne and Sydney and I terminated my consulting practice.

  • Letter to Australian Standards Assn June 1970
    ( View Paper )

    • Requesting reduced sampling rates when concrete produced under statistical quality control, to provide incentive for adoption of such control.

  • Cash Penalties Can Be Fair and Effective
    ( View Paper )

    • Concrete International, September 1982

    A detailed mathematical justification

  • Early Age/Equivalent Age
    ( View Paper )

    • I first used the maturity concept for steam curing in the mid 1950s using mercury in glass thermometers. Comameters became available in the early 1980s but electronic temperature logging awaited the James meter in the late 1980s and the maturity concept was replaced by Arrhenius Equivalent Age. At this point I developed my own concept of predicting future strength. This was further refined by my discovery of the "kink" in the strength v log Equiv Age relationship in the mid 1990s. The story given here is extracted from the second edition of my book as I cannot trace a suitable paper written at the time.

  • Regulating Concrete Quality
    ( View Paper ) ( View Powerpoint )

    • OWICS (Our World in Concrete & Structures) symposium, Singapore, August 2004.

    Updated but not very new except for inclusion of cusum (when will they ever learn!)

  • EN206: Can we do better? circa 2001
    ( View Paper )

    • Explaining why my multigrade technique is better than theirs

  • P2P and the Australian Experience
    ( View Paper )

    • An article prepared by K. Day to assist the American NRMCA in their struggle to bring American specification and control techniques out of the dark ages!

Other Papers[Back on top]

  • Original Company Brochure of Concrete Advice Pty Ltd: 1973
    ( View Paper )

  • Concrete in 1991 (written 1981)
    ( View Paper )

    • A paper to a Singapore symposium in 1981 looking 10 years into the future, already foreseeing flowing concrete and "Just-in-Time" mix design even before computers were generally available.

  • The Conad System of Concrete Quality Control (circa 1995)
    ( View Paper )

    • A 4 page condensed history of the 40 year development period of the technique. The incredible degree of resistance to progress is clearly shown and it is even more surprising that there is still resistance to such techniques in USA.

  • High Strength Concrete, State of the Art (1996)
    ( View Paper ) ( View Powerpoint )

    • A shortened version of my "General Reporter" contribution to BHP96, (Beton Haut Performance) a major international symposium in Paris, May 1996. The contribution summarised 28 of the submitted papers

  • Alkon2000
    ( View Powerpoint )

    • An extensive Powerpoint only presentation of the Conad system as it was in 2000 presented at the Alkon session at an ACI symposium in Las Vegas. This presentation resulted in the sale of the Conad system to Maricopa Readymix - the first American client.

Recent Papers[Back on top]

Recent Publications[Back on top]

  • Perspective on Prescriptions
    ( View Paper )

    • Concrete International July 2005

    A condemnation of the still current US practice of prescription specifications

  • An Australian Perspective on P2P Initiative: Lessons to learn
    ( View Paper )

    • Indian Concrete Journal Dec 2005

  • Workshop on Specifications and Producer QC
    ( View PowerPoint )

    • Presentation to the Washington seminar announced below

  • Ken Day Seminar Announcement
    ( View PDF )

    • The circular announcing the Ken Day Washington seminar

  • Multigrade, Multivariable, Cusum, Quality Control
    ( View MMC web page ) ( View PowerPoint )

    • The written paper and Powerpoint presentation delivered at the 2006 Montreal Conference of Canmet/ACI on the occasion of the presentation of a lifetime award to K. Day

  • Guarantee of concrete quality
    ( View PDF )

    • An article written by editor's request for the ICJ (Indian Concrete Journal) in December 2005

FIB 2008 (Holland)[Back on top]

  • P2P – an assessment of the situation on Prescription to Performance specifications in USA
    ( View Paper ) (View Powerpoint )

  • JIT – Just in Time mix design, a view that concrete mixes should be adjusted immediately before batching
    ( View Paper ) (View Powerpoint )

  • OCQ – Optimised Quality Control
    ( View Paper )

Singapore OWICS 2009 address[Back on top]

 

Delhi March 2011 address[Back on top]

  • Ken’s address - Role of Specification, Mix Design, QC and QA in Developing Durable, Economical and Sustainable Concrete Construction. Delhi March 2011
    ( View Paper ) (View Powerpoint )

 

Tasmania September 2011 address[Back on top]

  • Ken’s address - Role of Specification, Mix Design, QC and QA in Developing Durable, Economical and Sustainable Concrete Construction. Tasmania September 2011
    ( View Paper ) (View Powerpoint ) ( View Flash )