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Table 4.1. Matrix of field testing issues and applications.
Agency or Organizationa
Issue/Application Hamilton
UT c d Texas e
NRMCA County EBMUD TAMU
Austinb DOT
(OH)
Technical Issue
Long-term strength gain/excavatability
Short-term strength gain/constructibility
Corrosion of metals in CLSM
Productivity and cost
Resistance to freezing and thawing
Construction issues (i.e., pipe floating)
Settlement
Use of by-product materials
Environmental issues
Permeability/leak detection
CLSM Application
Backfill
Utility bedding
Void fill
Bridge approach
a
Information on productivity and cost was also obtained from the New York DOT but is not included herein (for
conciseness). Also, a field test was planned with the Florida DOT, but permitting issues prevented the field test from
occurring.
b
UT Austin = University of TexasAustin
c
NRMCA = National Ready-Mix Concrete Association
d
EBMUD = East Bay Municipal Utility District
e
TAMU = Texas A&M University
Field Test at the University mix concrete producers, each of whom had experience with
of TexasAustin producing CLSM for various applications. The mixture pro-
portions were based primarily on experience gained from the
Introduction laboratory portion of this study. Mixtures were selected to span
Significant field testing was performed at the J. J. Pickle a range of materials and proportions and to generate strengths
Research Campus at the University of TexasAustin. The that would result in various degrees of ease of excavatability.
main goals of these tests were to evaluate the use of CLSM as Intentionally, no trial mixing was performed using materials
trench backfill; to establish a link between laboratory tests and similar to those used in the field test, specifically to deter-
field performance; and to study the impact of materials, mix- mine if prescriptive mixture proportions (e.g., cement con-
ture proportions, and curing regime on long-term strength tent, aggregate content, water added to achieve target flow)
gain and excavatability. would result in desirable mixtures (e.g., target flow, mini-
mal segregation/bleeding). On-site adjustments were available
for these mixtures if they arrived at the field test either too dry
Materials and Mixture Proportions
or too wet in consistency, as discussed later. However, if the
Six CLSM mixtures were included in this study, as shown in water added to the drier mixtures resulted in excessive bleed-
Table 4.2. Each of the mixtures was procured from local ready- ing or segregation, no further water was added.
Table 4.2. Mixture proportions for excavation study.
Type I Fly Concrete Water Air Mixture
Fly Ash Flow Density
Mixture Cement Ash 3) Sand Content Content Temperature
(kg/m (mm) (kg/m3)
(kg/m3) Type (kg/m3) (kg/m3) (%) (°C)
Flash 0 Class C 224 1672 165 4.0 190 35.2 2179
A1 30 0 130 130 29.5 200 33.6 1539
A2 60 0 130 130 28.5 220 34.5 1539
Paste 60 Class F 1195 485 485 1.0 420 42.5 1795
F1 30 Class F 180 175 175 2.25 100 36.8 2051
F2 60 Class F 180 175 175 2.5 140 35.2 2083
"" = not used
