Concrete Maturity: New Approaches in Developing MaturityStrength Relations for use in FastTrack Pave

1
Concrete Maturity New Approaches in
Developing Maturity-Strength Relations for use in
Fast-Track Pavement Applications
2
by Matthew Lacome Trieu Hoang - Graduate
Students, UCD Kevin L. Rens - Associate
Professor, UCD
3
Research Team
PhD Students Matthew Lacome Saharat
Buddhawanna M.S Students Matthew Lacome
Elie Hamamji Alberto Mezarena
Mohammad Abu-Hassan Trieu
Hoang Erik Holck B.S.
Student Myron Lacome
4
More appropriate title
Concrete Maturity Results of Two State Highway
Agency Questionnaire surveys
5
Outline

• 1998 Questionnaire
• 2000 Questionnaire
• UCD NSF Project

6
Further Information
www.cudenver.edu/krens Research Button NSF
7
Questionnaires

• Good source of capturing current pulse
• Keep questions Yes/No
• Optional Comment Fields
• 2 pages maximum

8
Questionnaires

• ASCE (1997, 2000)
• Failure Analysis / Education
• USA CERL (2001)
• Dam Safety
• DOT (1998, 2000)
• Concrete Maturity

9
1998 Questionnaire

• Sent to all 50 State Highway Departments
• Each wave of letter sending yields
• 50 return
• 44/50 eventually responded 88
• Chapter of Matthew Lacome 2000 Thesis
• 9 yes/no questions comment field

10
1998 Questionnaire

• Objective
• Gain better understanding of current maturity
  trends
• Investigate difficulties and limitations with the
  current method
• Gauge interest in studying maturity

11
1998 Questionnaire
Yes No
1) Familiarization with concrete maturity 2)
Utilization of concrete maturity 3)
Familiarization with ASTM C1074 4) Utilization
of ASTM C1074

• 5
• 57 43
• 26
• 35 65

12
1998 Questionnaire
Yes No

• Aware of ASTM limitations (Early age temperature
  Constant curing temperatures)
• 8) Favorable opinion of modifying ASTM
• 6) Have modified ASTM C1074
• Interested in learning about how to remove
  limitations

• 47
• 14
• 83
• 71 21

13
1998 Questionnaire
Yes No
7) Favorable opinion of research in the area of
early-age temperature and its effect on the
maturity relationship
69 12
14
1998 Questionnaire
Yes / No Summary

• DOTs are familiar with the maturity concept
• DOTs are interested in the concept
• Some DOTs use the current ASTM Standard

15
1998 Questionnaire

• 17 respondents provided written comments
• Past and current maturity involvement
• Opinions on current limitations
• Opinions on field applications

16
1998 Questionnaire
Written comment summary -- General

• Maturity concept is being used in the field but
  without following ASTM C1074
• Current methods of developing the
  strength-maturity relationship are cumbersome and
  not practical
• Current limitations can produce inaccurate results

17
2000 Questionnaire

• Sent to all 50 State Highway Departments
• Each wave of letter sending yields
• 50 return
• 43/50 eventually responded 86
• Chapter of Trieu Hoang 2001 thesis
• 7 yes/no questions comment field

18
2000 Questionnaire

• Objectives
• Monitor change and usage regarding the maturity
  method sent to same individuals
• Provide guidance for the UCD study
• Curing temperatures, mix design, temperature-time
  histories
• Investigate difficulties and limitations with the
  current methods

19
2000 Questionnaire
Yes No

• Involvement in concrete maturity research during
  the past 2 years.
• 2) Incorporation of maturity in projects during
  the past 2 years.

40 60 40 60
20
2000 Questionnaire
Yes No
3) Agreement on 5, 25, 50 degree Celsius curing
temperatures. 4) Agreement on 0.53 and 0.28 w/c
ratios. 5) Inclusion of high performance mix
design?
84 9 84 9 47 53
21
2000 Questionnaire
Yes No
77 14 91 7
6) Agreement of utilization of actual field
temperatures to cure cylinders. 7) Interested in
learning how to improve the maturity method.
22
2000 Questionnaire
Yes / No Summary

• A significant interest exists regarding the
  maturity concept and in the current UCD NSF
  effort.
• More DOTs have been utilizing the maturity
  concept during the past 2 years including those
  who have utilized for the first time.
• Agreement exists with the UCD team on curing
  temperatures, water cement ratios, and actual
  field recorded temperature time histories.

23
2000 Questionnaire

• 28 respondents provided written comments
• Curing temperature range
• Water-cement ratio range
• Submission of high performance mix design
• Utilization of field temperature time histories
• General Maturity and ASTM C1074 comments

24
2000 Questionnaire
Written comment summary -- General

• General agreement on temperature extremes some
  states involve projects at higher temperatures.
• Most common w/c ratios are 0.35 0.45.
• Not too much use for 7,500 psi and higher mix
  designs (Minnesota and Oregon).
• Several states use actual field temperatures for
  curing cylinders.

25
1998 2000 Questionnaire Specific Results

• Indiana, Nevada, and Colorado require conditions
  similar to the field for curing cylinders.
• Iowa and Michigan use the Modified Iowa Method
• Use of maturity meters on beams cast in the field
  (again maintaining the field integrity)
• Florida is somewhat skeptical and wants to see a
  general field curve correlated to mass concrete
  results as proof. (suggested this be a part of
  the UCD NSF research)
• Texas also uses a modified method to develop
  maturity strength relationships.

26
1998 2000 Questionnaire Specific Results
States specifying maturity method to be used in
projects since 1998.
       One project 11 states (64.7 )       
Two projects 1 state (5.9 )        Three
projects 2 states (11.8 )        Four
projects 2 states (11.8 ) Seven
projects 1 state (5.9 )
Florida
Indiana Michigan
27
1998 2000 Questionnaire Specific Results
States specifying maturity method for the first
time

• Nebraska
• Nevada
• New Mexico

28
UCD NSF ProjectObjectives

• Study limitations
• Early age temperature on long term ultimate
  strength
• Try to determine the point in time when
  temperature no longer affects ultimate strength
• Constant curing temperature
• Investigate the effects of early age varying
  temperatures on ultimate strength

29
UCD NSF Project

• 3 year project
• Year 1
• Develop temperature time control system
• Choose normal and high performance mix
• Develop equivalent age maturity relationships
• 5, 25, 50 degree Celsius constant temperatures

30
Normal Strength Concrete --(5oC,25oC,50oC.)
31
High Strength Concrete --(5oC,25oC,50oC.)
32
UCD NSF Project

• Year 2
• Determine times where temperature does not
  control limiting strength for chosen temperatures
  and mixes.
• For both mixes, use step function temperature
  time histories.
• Cold to warm, warm to cold, warm to hot, hot to
  warm.
• Year 3
• Use more realistic temperature time histories
• Can we improve the ASTM standard?

33
?
Questions ?? . . . Thank You
www.cudenver.edu/krens