new technology-based approach to advance higher volume fly ash concrete with acceptable ...

232 Pages·2008·3.53 MB·English

by  Sushant Upadhyaya

[2008]

NEW T -B
ECHNOLOGY ASED
A A H
PPROACH TO DVANCE IGHER
V F A C
OLUME LY SH ONCRETE WITH
A P
CCEPTABLE ERFORMANCE
New Technology-Based Approach to
Advance Higher Volume Fly Ash
Concrete With Acceptable Performance

FINAL REPORT (2008)

Start Date: July 1, 2006
End Date: June 30, 2008 (DOE funding cut on March 30, 2007)

Authors:

Karthikeyan H. Obla, Sushant Upadhyaya, Dimitrios Goulias, Anton K. Schindler, and
Nicholas J. Carino

Report Issue Date: August 2008

Subcontract No. 98-166-NRMCA
DOE Award Number 05-CBRC-M20
RMC Research & Education Foundation Project No. 07-09

Committee:
Contractor:
Karthikeyan H. Obla and Colin L. Lobo
National Ready Mixed Concrete Association
900 Spring Street, Silver Spring, MD 20910

Sub Contractors:
Dr. Dimitrios Goulias
University of Maryland
Department of Civil and Environmental Engineering, College Park, MD 20742
Dr. Nicholas J. Carino, Concrete Materials Consultant
National Institute of Standards and Technology (retired)
Gaithersburg, MD 20886
Dr. Anton Schindler
Auburn University
Department of Civil Engineering, Auburn, AL 36849

Disclaimer

This report was prepared as an account of work sponsored by an agency of the United
States Government. Neither the United States Government nor any agency thereof, nor
any of their employees, makes any warranty, express or implied, or assumes any legal
liability or responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product or process disclosed, or represents that its use would not
infringe privately owned rights. Reference herein to any specific commercial product,
process, or service by trade name, trademark, manufacturer, or otherwise does not
necessarily constitute or imply its endorsement, recommendation, or favoring by the
United States Government or any agency thereof. The views and opinions of authors
expressed herein do not necessarily state or reflect those of the United States Government
or any agency thereof.

This report has been prepared solely for information purposes. It is intended solely for
the use of professional personnel, competent to evaluate the significance and limitations
of its content, and who will accept full responsibility for the application of the material it
contains. The National Ready Mixed Concrete Association and any other organizations
cooperating in the preparation of this report strive for accuracy but disclaim any and all
responsibility for application of the stated principles or for the accuracy of the content or
sources and shall not be liable for any loss or damage arising from reliance on or use of
any content or principles contained in this presentation. Unless otherwise indicated, all
materials in this presentation are copyrighted to the National Ready Mixed Concrete
Association. All rights reserved.

© 2008 National Ready Mixed Concrete Association.

Abstract

The use of fly ash in concrete has received significant attention over recent years due to
environmental concerns regarding its disposal and potential for use as a cementitious
material with its ability to provide significant benefits to concrete. While fly ash content
less than 25% of total cementitious content is routinely used in concrete, high-volume fly
ash (HVFA) concrete is not common due to perceived lower early-age strengths. The
objective of this study was to demonstrate using maturity based techniques that the
beneficial effects of high in-place temperature may be able to compensate for the slower
rate of strength gain in HVFA concrete that is typically observed when tested under
standard laboratory temperature conditions. In addition, different methods (match-cured
cylinders, pullout testing) were used to estimate the early-age in-place strength of HVFA
concrete to confirm the maturity predicted strengths. The results have shown that the
standard and field-cured cylinder strengths underestimate the in-place concrete strength.
Higher in-place temperatures due to the mass characteristics of structural elements
resulted in increased early age in-place strengths, adequate for construction scheduling,
as measured by match-cured cylinders, pullout testing, and the maturity approach.

Keywords: Concrete, Fly Ash, Supplementary Cementitious Materials, Maturity, Pullout
Test.
Table of Contents

Executive Summary ............................................................................................................ 1 
Chapter 1  – Introduction ................................................................................................ 2 
Chapter 2  – Background ................................................................................................ 5 
2.1 Maturity Method ....................................................................................................... 5 
2.2 Pullout Test ............................................................................................................... 7 
2.3 Match Curing ............................................................................................................ 7 
2.4 Push out Cylinders .................................................................................................... 7 
Chapter 3  – Experimental Work – Mortar ..................................................................... 9 
3.1 Materials ................................................................................................................... 9 
3.2 Mixing Mortar ......................................................................................................... 11 
3.3 Mortar Testing ........................................................................................................ 11 
3.3.1 Fresh Mortar Tests ............................................................................................... 11 
3.4 Mixture Proportions ................................................................................................ 12 
3.5 Discussion of Test Results ...................................................................................... 15 
3.5.1 Fresh Mortar Properties ....................................................................................... 15 
3.5.2. Compressive Strength ......................................................................................... 18 
3.5.3. Calculation of Activation Energy ....................................................................... 20 
Chapter 4  – Experimental Work – Concrete ............................................................... 27 
4.1 Materials ................................................................................................................. 27 
4.2 Mixing Concrete ..................................................................................................... 27 
4.3 Concrete Testing ..................................................................................................... 27 
4.3.2 Hardened Concrete Tests ..................................................................................... 27 
4.4 Mixture Proportions ................................................................................................ 34 
4.5 Discussion of Test Results ...................................................................................... 35 
4.5.1 Fresh Concrete Properties ................................................................................... 35 
4.5.2 Standard-Cured Strength Results and Strength-Maturity Relationship ............... 35 
4.5.3 Pullout Force Test Results and Pullout Force Versus Strength Correlation ........ 39 
4.5.4 In-Place Strength Estimates Based on Field-Cured and Match-Cured Cylinder
Strengths ....................................................................................................................... 42 
4.5.5 In-Place Strength Estimates Based on Pullout and Maturity ............................... 45 
Chapter 5  – Semi-Adiabatic Calorimetry Testing ....................................................... 51 
5.1 Quantifying the Total Heat of Hydration of the Cementitious Materials ............... 51
5.2 Quantifying the Degree of Hydration Development ............................................... 52 
5.3 Temperature Sensitivity of Cementitious Materials ............................................... 53 
5.4 Modeling the Heat Generation and Temperature Associated with Hydration ........ 53 
5.5 Experimental Work ................................................................................................. 54 
5.6 Test Data and Discussion of Results ....................................................................... 55 
Chapter 6  – Conclusions .............................................................................................. 59 
References ......................................................................................................................... 60 
Appendix A ....................................................................................................................... 64 
Appendix B ....................................................................................................................... 72 
Appendix C ....................................................................................................................... 83 
Appendix D ....................................................................................................................... 85 
Appendix E ....................................................................................................................... 89
List of Figures

Figure 2.1 Pullout setup (Carino 2004)............................................................................... 7 
Figure 3.1 Temperature sensor (iButton®) ....................................................................... 12 
Figure 3.2 Setting times of mortar mixtures ..................................................................... 16 
Figure 3.3 Compressive strength vs. actual age (35% FA-A mixture) ............................. 19 
Figure 3.4 Compressive strength vs. actual age (35% FA-C mixture) ............................. 20 
Figure 3.5 Rate constant vs. temperature-control mixture (AE-41400l J /mol) ............... 22 
Figure 3.6 Rate constant vs. temperature-20% FA-A (AE-48100 J /mol) ........................ 22 
Figure 3.7 Rate constant vs. temperature-35% FA-A (AE-l5600 J /mol) ........................ 23 
Figure 3.8 Rate constant vs. temperature-50% FA-A (AE-33400 J /mol) ........................ 23 
Figure 3.9 Rate constant vs. temperature-35% FA-B (AE-33000 J /mol) ........................ 24 
Figure 3.10 Rate constant vs. temperature-35% FA-C (AE-28300l J /mol) ..................... 24 
Figure 3.11 Arrhenius plots for the various mixtures ....................................................... 26 
Figure 4.1 Match cure system showing 8 match-cured cylinder molds connected to a
micro-controller computer ................................................................................................ 28 
Figure 4.2 Custom 8 × 8 × 8-in. cube mold ...................................................................... 29 
Figure 4.3 Cube molds with pullout inserts at the centers of the 4 side faces .................. 30 
Figure 4.4 Pullout equipment ............................................................................................ 30 
Figure 4.5 Field block with pullout inserts and temperature sensors ............................... 31 
Figure 4.6 Concrete block curing in field. ........................................................................ 32 
Figure 4.7 Concrete slab with cast-in-place cylinders and temperature sensors .............. 33 
Figure 4.8 Slabs with cast-in-place cylinders, floating inserts and field cure cylinders
(The red marking are the pullout inserts, field-cured cylinders are placed outside the slab
and the cast-in-place cylinders are within the slab) .......................................................... 34 
Figure 4.9 Maturity model- control mixture ..................................................................... 37 
Figure 4.10 Maturity model- 35% FA-A mixture ............................................................. 37 
Figure 4.11 Maturity model- 50% FA-A mixture ............................................................. 38 
Figure 4.12 Maturity model- 35% FA-C mixture ............................................................. 38 
Figure 4.13 Compressive strength vs. pullout force relationship-control mixture ........... 40 
Figure 4.14 Compressive strength vs. pullout force relationship-35% FA-A mixture ..... 41
Figure 4.15 Compressive strength vs. pullout force relationship-50% FA-A mixture ..... 41 
Figure 4.16 Compressive strength vs. pullout force relationship-35% FA-C mixture ..... 42 
Figure 4.17 Compressive strength vs. age for different curing conditions (Control
mixture-block) ................................................................................................................... 43 
Figure 4.18 Compressive strength vs. age for different curing conditions (Control
mixture-slab) ..................................................................................................................... 43 
Figure 4.19 Compressive strength vs. age for different curing conditions (35% FA-A
mixture-block) ................................................................................................................... 44 
Figure 4.20 Compressive strength vs. age for different curing conditions (35% FA-C
mixture-block) ................................................................................................................... 44 
Figure 4.21 Compressive strength vs. age for different curing conditions (50% FA-A
mixture-slab and block) .................................................................................................... 45 
Figure 4.22 Comparison of strength obtained from various methods vs. equivalent age
(Control-mixture block) .................................................................................................... 48 
Figure 4.23 Comparison of strength obtained from various methods vs. equivalent age
(50% FA-A-block) ............................................................................................................ 48 
Figure 4.24 Comparison of strength obtained from various methods vs. equivalent age
(35% FA-A block) ............................................................................................................ 49 
Figure 4.25 Comparison of strength obtained from various methods vs. equivalent age
(35% FA-C block)............................................................................................................. 49 
Figure 4.26 Comparison of strength obtained from various methods vs. equivalent age
(Control mixture-slab) ...................................................................................................... 50 
Figure 4.27 Comparison of strength obtained from various methods vs. equivalent age
(50% FA-A-slab) .............................................................................................................. 50 
Figure 5.1 Effect of change in fly ash A proportions and w/cm on cumulative heat of
hydration development ...................................................................................................... 56 
Figure 5.2 Effect of change in fly ash A proportions and w/cm on rate of hydration ...... 57 
Figure 5.3 Effect of change in fly ash type and w/cm on cumulative heat of hydration
development ...................................................................................................................... 58 
Figure 5.4 Effect of change in fly ash type and w/cm on rate of hydration ...................... 58 
Figure A.1 Specimens for task 3 ....................................................................................... 68