Design Team:

1

Freeze-Thaw Concrete Chamber Controller
Abstract
End-Product Description
The new control system for the concrete
freeze-thaw test chamber includes a new control
system and software to run the 300-cycle test
used by the DOT. The new system has streamlined
the hardware components in the test chamber to
allow for individualized control of the drains
and pumps used to fill and empty the test
chamber. It is also possible to take temperature
readings for each test sample, and outdated and
inessential equipment has been removed. The end
result is a more efficient test system with
greater versatility that will be easier to
upgrade as changes are needed.  
The objective of this project is to develop a
hardware and software system to interface with
the Iowa Department of Transportation freeze-thaw
units. Upon completion of the project a new
system will be in place that will be easy to
maintain and use that can be upgraded as needed.
Introduction

• General Background
• The Iowa Department of Transportation uses a
  freeze-thaw test unit that tests concrete
  samples to determine how they will react to
  different weather climates.
• The test runs 300 cycles of freeze/thaw with
  tight temperature and time requirements.
• The hardware and software that run the tests
  have been in place for almost 20 years
• Maintenance and upgrades of the current system
  are costly and difficult.
• Technical Problem
• A new control system is needed to replace
  existing hardware.
• New GUI software needs to be developed to
  replace the existing BASIC software.
• The hardware/software solution must be flexible
  enough to allow for inexpensive maintenance and
  upgrades so that the new system can be in place
  for 10-20 years
• Operating Environment
• The lab experiences extreme changes of heat and
  humidity throughout the test/year.
• Intended Users and Uses
• Engineers at the DOT will be responsible for
  the use maintenance of the system.
• Assumptions
• The Iowa DOT will be able to order required
  equipment in a timely manner.
• The hardware that will be reused is already
  documented

Figure 2 Antiquated Equipment to be Replaced
Technical Approach
An improved control package for the Iowa DOT
concrete freeze-thaw chamber will require
consideration of a few options to determine what
will best satisfy the needs of the system and its
users. Important things to consider include the
cost of replacement of hardware, time required to
develop software, and the ability for the chosen
option to be upgraded in the future. There are
three main options to choose from for the new
hardware/software system. They are debug the
non-functional Lab View/National Instruments
control system that was mentioned in the general
background section of this plan, create a new
piece of software using Lab View to run the
National Instruments control board, or purchasing
a new control system from an outside vendor and
designing a software package to run the tests.
These three options will be evaluated for their
cost, development time and upgrade potential and
discussed with the Iowa DOT to determine what
will be the best option for the project. If an
outside control system is purchased it will be
necessary to determine what language will be used
to write the control software.
Figure 1 Diagram of Freeze-Thaw Process
Design Requirements

• Design Objectives
• New software will replace the current system
  and be more reliable and upgradeable.
• New hardware must be able to work with new
  operating system and be more reliable.
• Control of multiple (time permitting)
  freeze-thaw chambers from one location.
• Functional Requirements
• Ability to run the A and B testing methods as
  defined by the ASTM C 666 97 standard.
• Ability to modify timing of the freeze-thaw
  cycles.
• New software will give user control of
  individual devices in test system(s).
• The new control system will perform all of the
  functions of the previous system.
• Design Constraints
• Hardware must withstand a stressful environment
  that is not temp/humidity controlled.
• New control system hardware must work with
  existing freeze-thaw chamber equipment.
• The freeze-thaw cycle parameters must be
  easily changed through the user interface.
• Milestones
• Assembly of the new control system hardware.
• Simulation of a single freeze-thaw test cycle
  for both test methods.

Testing Approach
The system will be tested to verify that there is
control of individual mechanical elements and
that it is possible to take temperature readings
as needed. Next, testing will verify that the
correct temperature and time points are read for
changes from freeze-to-thaw and thaw-to-freeze
cycles and that the software accurately controls
the individual elements in the test runs.
Finally, the system will be run through several
test cycles to confirm that there are no bugs in
the system that will preclude full implementation
of the test chamber.
Personnel and Financial Budget
Estimated Personnel Budget 500 Hours Estimated
Financial Budget 8600 Poster
Materials 50 Control System 7000 Misc
Electronic Components 50 PC 1500 TO
TAL 8600
Project Team Information

Design Team
Advisor Dr. James Davis davis_at_iastate.edu Project
Web Site http//seniord.ee.iastate.edu/may0312
Client Kevin Jones kevin.jones_at_dot.state.ia.u
s Iowa Department of Transportation Ames, IA
50010
Craig Rueter CprE crueter_at_iastate.edu Stev
e Spencer CprE einstein_at_iastate.edu J
ason Stowe CprE stowe_at_iastate.edu Eric
Wulf CprE ewulf_at_iastate.edu