ArticlePDF Available
www.concreteinternational.com | Ci | MARCH 2015 53
Novel Ultra-High-
Performance Glass
Concrete
New material used to fabricate pedestrian bridges on the University of
Sherbrooke campus
by Arezki Tagnit-Hamou, Nancy Soliman, Ahmed F. Omran, Mohammed T. Mousa, Nicolas Gauvreau, and
MFrancine Provencher
Ultra-high-performance concrete (UHPC) is dened
worldwide as concrete with superior mechanical,
ductility, and durability properties. A typical UHPC is
composed of cement, quartz powder (QP), silica fume (SF),
quartz sand (QS), and steel bers.1 UHPC achieves compressive
strengths of at least 150 MPa (22,000 psi), exural strengths
up to 15 MPa (2200 psi), elastic moduli of up to 45 GPa
(6500 ksi), and minimal long-term creep or shrinkage.2 It can
also resist freezing-and-thawing cycles and scaling conditions
without visible damage, and it is nearly impermeable to
chloride ions.3 UHPC is thus a promising material for special
prestressed and precast concrete elements (decks and
abutments for lightweight bridges and marine platforms;
urban furniture; and precast walls), concrete repair, and
architectural façade elements.4
Although UHPC is relatively expensive to produce, it
presents some economic advantages because its enhanced
properties allow:
Reduction or elimination of passive reinforcement in
structural elements;
Reductions in the thickness and self-weight of concrete
elements; and
Increases in service life accompanied with reductions in
maintenance costs.5
UHPC is designed with a very high cement content
ranging between 800 and 1000 kg/m3 (1350 and 1690 lb/yd3),
which leads to high production costs, consumes natural
sources, and increases CO2 emissions. These factors and
others such as a relatively high SF content (25 to 35% by
weight of cement) are considered impediments to UHPC use
in the concrete market.
Ultra-high-performance glass concrete (UHPGC) is a new
type of UHPC that constitutes a breakthrough in sustainable
concrete technology,6 as it comprises granulated post-consumer
glass with a specic particle-size distribution (PSD) developed
using glass sand, high amounts of glass powder, and moderate
contents of ne glass powder. UHPGC is a ber-reinforced
concrete characterized by a very dense microstructure, which
enhances durability via a discontinuous pore structure. While
UHPGC can be designed with less cement, SF, QP, and QS
than typical UHPC, it still contains bers and a high-range
water-reducing admixture (HRWRA).
UHPGC can be produced with low water binder ratio
(w/b), yet because the glass particles have zero absorption, its
rheological properties allow it to be practically self-placing.
Depending on UHPGC composition and curing temperature,
the concrete’s compressive strength can range from 130 to
260 MPa (20,000 to 40,000 psi), while exural strength can
exceed 15 MPa (2200 psi), tensile strength can exceed 10 MPa
(1500 psi), and elastic modulus can exceed 45 GPa (6500 ksi).
UHPGC is characterized by excellent durability. Due to its
high packing density and lack of interconnected pores,
UHPGC has negligible chloride-ion penetration, low mechanical
abrasion, and very high freezing-and-thawing resistance.
Pedestrian Bridges
Developing UHPGC was one of the main goals of the
University of Sherbrooke’s industrial chair on the valorization
of waste glass in materials. After a major research program,
this newly developed concrete was used to fabricate new
footbridges to replace deteriorated wooden structures on the
University of Sherbrooke campus, Sherbrooke, QC, Canada.
The technology enabled the designer to create thin sections
that are light, graceful, and innovative in geometry and form
at a relatively low cost. In addition, the structure is expected
to be durable with high abrasion and impact resistance.
54 MARCH 2015 | Ci | www.concreteinternational.com
Materials
As with any concrete or mortar,
UHPC rheology is strongly affected by
cement neness as well as the two most
reactive components in portland
cement—C3A and C3S. The cement
characteristics are even more critical in
the case of UHPGC, as the very low w/b
results in close packing of the cement
particles. It is particularly important to
select cement with the lowest contents
of C3A and C3S. The cement selected for
the UHPGC footbridges was formulated
with a low C3A amount to provide high
sulfate resistance. The cement properties
included: Bogue composition of 50%
C3S, 25% C2S, 14% C3A, and 11%
C4AF; specic gravity of 3.21; Blaine
neness of 370 m2/kg; and D50 of 11 µm.
Other materials used in the UHPGC
mixture included:
SF compliant with CAN/CSA-
A3000-13 “Cementitious materials
compendium” specications with
silica content of 99.8%, specic
gravity of 2.20, D50 of 0.15 µm, and
specic surface area of 20,000 m2/kg;
QS with silica content of 99.8%,
specic gravity of 2.70, D50 of 250 µm,
and maximum particle size of 600 µm;
Glass powder (GP) with silica
content of 73%, specic gravity of
2.60, maximum particle size of
100 µm, and Na20 content of 13%;
Polycarboxylate-based HRWRA,
marketed as ViscoCrete-6100 (Sika);
and
Polyvinyl alcohol (PVA) bers with
13 mm (0.5 in.) length and 0.2 mm
(0.008 in.) diameter.
Concrete mixture
The mixture design was developed in
three steps. In the rst step, the packing
density of the granular composition
(QS, GP, cement, and SF) was optimized
to 0.78% using the compressible
packing model.7 The resulting mixture
comprised 410 kg/m3 (690 lb/yd3) of GP.
In the second step, the optimum
HRWRA dosage was determined for a
range of w/b values, yielding the
rheological characteristics needed to
obtain a self-consolidating matrix as
well as adequate strength. In the third
step, the ber content was optimized
as needed to improve the UHPGC
ductility without signicantly altering
the rheological properties of the
fresh mixture.
Table 1 provides the compositions for
the UHPGC mixtures with w/b of 0.24
used in this project.
Design
The footbridges were designed to
meet the university’s architectural and
structural requirements for pedestrian
use as well as to be in compliance with
the university’s regulation on sustainable
development. Because the mechanical
properties of the UHPGC allowed the
spans to be constructed with relatively
small cross sections, each bridge had a
total weight of around 4000 kg (8800 lb).
The structural system consisted of an
arch slab 4910 mm (193 in.) in length,
2500 mm (98 in.) in width, and 75 mm
(3 in.) in thickness supported by
longitudinal ribs of variable height and a
constant width of 130 mm (5 in.). Using
the mechanical properties determined
during the testing program, the section
was designed to meet strength and
serviceability limits as per the university’s
requirements. The arch slab was
reinforced with welded wire reinforce-
ment (M10 at 300 mm [12 in.] in both
directions) placed at the midheight of
the slab. Each rib was reinforced with a
single M20 reinforcing bar located near
the bottom of the rib. Figure 1(a) shows
the footbridge reinforcement arrange-
ment and Fig. 1(b) provides the concrete
dimensions. One footbridge was
instrumented with thermocouples and
vibrating wire strain gauges so that
temperature and deformation could be
monitored over time.
Formwork
The mold for the bridges was built at
the Bétons Génial, Inc., plant and then
transported to the university’s integrated
laboratory for innovative and sustainable
materials and structural valorization
research. Bétons Génial, Inc., designed
and built a reusable wooden mold
integrating a urethane-rubber facing
with specic shore hardness. The facing
Table 1:
UHPGC mixture design
Materials kg/m3
Type HS cement 555
Silica fume (SF) 205
Glass powder (GP) 410
Water 226
Syntactic fiber 32.5
Quartz sand (QS) 888
HRWRA (solid content) 17
Note: 1 kg/m3 = 1.69 lb/yd3
was designed to produce a textured,
non-slip walking surface on the decks
and very smooth, joint-free surfaces on
other surfaces of the bridges (Fig. 2).
Although UHPGC shrinkage is very
low, the liner material was selected to
accommodate concrete shrinkage and
minimize the risk of creating micro-
cracks during concrete curing. The mold
was designed so that the bridge could be
cast upside down, allowing the relatively
complex shape to be formed with the
integral non-slip areas on the deck.
Production
The UHPGC was produced at the
University of Sherbrooke laboratory
using a pilot-scale automatic concrete
plant with a paddle-type stationary pan
mixer with a 500 L (18 ft3) capacity. To
achieve a homogeneous mixture and
avoid particle agglomeration, all powder
materials were dry mixed for 10 minutes
before the water and HRWRA additions.
About half of the HRWRA was diluted
in half of the mixing water, and this
was gradually added over the next 3 to
5 minutes of mixing time. The remaining
water and HRWRA as well as the bers
were then added over the following 3 to
5 minutes of mixing time. The total
mixing time was 20 minutes.
Four batches of concrete were
produced for a total of 2.0 m3 (3 yd3) for
each footbridge. Concrete production
and placement took 2 hours. Once the
four batches had been loaded into the
hopper, the UHPGC’s uidity and
self-placing properties allowed for
placing the concrete into the mold in
fewer than 12 minutes without external
www.concreteinternational.com | Ci | MARCH 2015 55
Fig. 1: Bridge schematic: (a) longitudinal section at centerline; and (b) bottom view showing
concrete dimensions. Dimensions are in mm (nearest in.)
(a)
(b)
75
(3)
75
(3)
75
(3)
75
(3)
75
(2.95)
119
(5)
272
(11)
1508
(59)
496
(20)
130
(5)
300
(12)
100
(4)
2500
(99)
455
(18)
455
(18)
455
(18)
455
(18)
150
(6)
328
(13)
4910
(193)
4910
(193)
280×1138
(11x45)
EPS foam block;
216 (9) depth
150×1578
(6x62)
EPS foam block;
depth varies
Bottom of flange
Bottom of ribs
Bearing surface
Fig. 2: The footbridge
mold was designed to
provide formed
surfaces on all
exposed faces: (a) a
wooden insert was
fabricated in the shape
of the deck wearing
surface and curbs; and
(b) the insert was used
as the master to cast
the urethane rubber
liner used for
production of the
footbridges
(a)
(b)
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vibration. While the UHPGC couldn’t be described as
self-consolidating, it owed extremely well. Only 1 minute of
internal vibration was required to ensure good compaction.
After casting, exposed concrete was covered with plastic
sheeting until the mold was removed. For each bridge, the
mold was removed 24 hours after placement. First, an
overhead crane was used to open the mold by separating its
two parts with straps and anchors (Fig. 3(a)). The bridge was
then lifted and rotated (Fig. 3(b)). After form removal,
plastic sheeting was placed over each footbridge to allow
continued curing.
The UHPGC’s fresh and rheological properties were
measured after mixing. Specimens needed for compressive,
tensile, and exural strength tests as well as modulus of
elasticity, resistance to mechanical abrasion, scaling, freezing-
Fig. 3: The footbridge was cast upside down. The mold base held the
urethane rubber liner shown in Fig. 2, and the mold was closed with
a separate wooden insert that formed the curved and ribbed bottom
surfaces of the footbridge: (a) the insert is removed from the mold
base, exposing the bottom concrete surfaces and the expanded
polystyrene blocks indicated in Fig. 1; and (b) the footbridge was
pulled from the mold using straps and anchors, and a steel frame
was attached in preparation for flipping the completed structure
(a)
(b)
and-thawing resistance, chloride-ion penetration, and resistivity
tests were then fabricated. Tests were performed according to
ASTM International standards. The samples were stored at
23°C (73°F) and 100% relative humidity (RH) for 24 hours
before mold removal, after which they were stored in a fog
room at 23°C (73°F) and 100% RH until testing.
Installation
Before the bridges were transported to their installation
sites, wooden and steel railings were attached (Fig. 4). A
simple atbed truck was used for transportation to the site
(Fig. 5), and a truck-mounted crane and straps were used to
lift and install the bridges on conventional concrete abutments
with neoprene bearing pads. Lifting and placing took a little
less than an hour.
Concrete Performance
Fresh properties
Tests were performed to obtain basic fresh concrete
properties including slump ow (ASTM C1437, “Standard
Test Method for Flow of Hydraulic Cement Mortar”), unit
weight, air content, and temperature (ASTM C185, “Standard
Test Method for Air Content of Hydraulic Cement Mortar”)—
values were 280 mm (11 in.) without tamping, 2231 kg/m3
(140 lb/ft3), 3.5%, and 22°C (72°F), respectively.
To examine the concrete’s ability for self-placement
without consolidation or segregation issues, various tests
normally carried out for self-consolidating concrete were
performed. The slump-ow diameter with the Abrams cone
(ASTM C143/C143M, “Standard Test Method for Slump
of Hydraulic-Cement Concrete”) was 780 mm (31 in.).
The time to reach a 500 mm (20 in.) spread diameter
(T500) was 6.8 seconds, which explains the relatively high
viscosity. The visual stability index (VSI) was 0, which
means no evidence of segregation.
To ensure the concrete ows adequately around the
reinforcement bars, the difference between the slump-ow
diameter and the J-Ring spread diameter should not exceed
Fig. 4: As final preparation before shipping to the jobsite, wooden
and steel railings were attached to the UHPGC curbs
www.concreteinternational.com | Ci | MARCH 2015 57
50 mm (2 in.) according to the German
SCC guideline8 or 10 mm (0.4 in.)
according to EFNARC.9 This value was
only 5 mm (0.2 in.) for the UHPGC,
indicating excellent passing ability. The
blockage ratio for the J-Ring test was
0.83. The self-leveling index for the
L-Box test with two steel rods was 1.0
(the limit accepted under the EFNARC
2002 guideline9 is between 0.80 and
1.0). The time for the leading edge of
the concrete to reach the end of the
600 mm (24 in.) long horizontal section
was 9.8 seconds. This mixture’s
enhanced fresh properties derive from
the large incorporation of glass powder
with zero absorption.
Mechanical properties
Compressive-strength tests were
carried out according to ASTM C39/
C39M, “Standard Test Method for
Compressive Strength of Cylindrical
Concrete Specimens,” on 100 x 200 mm
(4 x 8 in.) cylindrical specimens at
1, 7, 28, and 91 days after normal
curing. The 28- and 91-day compressive
strengths of this UHPGC were 96 and
127 MPa (14,000 and 18,500 psi),
respectively. The increase in compressive
strength of about 33% from 28 days to
91 days indicates the glass powder’s
pozzolanic reactivity.
Other test conducted at 28 and 91 days
included: indirect splitting tensile
strength according to ASTM C496/
C496M, “Standard Test Method for
Splitting Tensile Strength of Cylindrical
Concrete Specimens,” on 100 x 200 mm
(4 x 8 in.) cylindrical specimens;
exural strength according to ASTM
C78/C78M, “Standard Test Method for
Flexural Strength of Concrete (Using
Simple Beam with Third-Point Loading),”
on 100 x 100 x 400 mm (4 x 4 x 16 in.)
prisms; and modulus of elasticity
according to ASTM C469/C469M,
“Standard Test Method for Static
Modulus of Elasticity and Poisson’s
Ratio of Concrete in Compression,” on
100 x 200 mm (4 x 8 in.) cylinders.
Table 2 lists the concrete’s mechanical
properties.
Durability properties
Concrete abrasion was measured
according to ASTM C944/C944M,
Table 2:
Mechanical properties of UHPGC
Properties
Concrete age, days
1 7 28 91
Compressive strength, MPa 12 52 96 127
Splitting tensile strength, MPa 10 11
Flexure strength, MPa 10 12
Modulus of elasticity, GPa 41 45
Notes: 1 MPa = 145 psi; 1 GPa = 145 ksi
“Standard Test Method for Abrasion
Resistance of Concrete or Mortar
Surfaces by the Rotating-Cutter
Method.” The average value of the
relative volume loss index was 1.35 mm
(0.05 in.). For a typical UHPC, the
relative volume loss index ranges from
1.1 to 1.7 mm (0.04 to 0.07 in.),10 which
itself is small relative to that for HPC
(2.8 mm [0.11 in.]) and normal concrete
(4.0 mm [0.16 in.]).3
Scaling resistance was measured
according to ASTM C672/C672M,
“Standard Test Method for Scaling
Resistance of Concrete Surfaces
Exposed to Deicing Chemicals.” After
50 freezing-and-thawing cycles, the
scaled mass was 12 g/m2 (0.04 oz/ft2).
The scaled mass reported for UHPC in the
literature, varies from about 8 to 60 g/m2
(0.20 oz/ft2) for samples subjected to
Fig. 5: The completed footbridges were transported on a flatbed truck and installed with a truck-mounted crane
58 MARCH 2015 | Ci | www.concreteinternational.com
Fig. 6: Variations of deformation and temperature with time obtained from instrumented
bridge (Note: °F = 1.8 x °C + 32°)
-60
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
-1400
-1200
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
1200
1400
10 20 40 50 70
Deformation, μm/m
Temperature, °C
Time, days
Total deformation
Temperature
at centerline of deck
Temperature at edge beam
Isothermal deformation:
Total deformation minus
thermal expansion
of concrete
030 60
28 to 50 freezing-and-thawing cycles.11
Resistance to chloride-ion penetration
was evaluated per ASTM C1202,
“Standard Test Method for Electrical
Indication of Concretes Ability to
Resist Chloride Ion Penetration.” The
28- and 91-day specimens exhibited
values below 10 coulombs, indicating
“negligible” chloride-ion permeability.
Resistance to freezing-and-thawing
was measured according to ASTM
C666/C666M, “Standard Test Method
for Resistance of Concrete to Rapid
Freezing and Thawing.” Relative
dynamic modulus was 100% after
700 freezing-and-thawing cycles.
The resistivity test was carried out
on 100 x 200 mm (4 x 8 in.) cylindrical
sample after 91 days of curing. An
extremely high value of 3466 kΩ•cm
was obtained. For comparison, the
resistivity is 1130 kΩ•cm for traditional
UHPC without bers, 96 kΩ•cm for HPC,
and 16 kΩ•cm for normal concrete.3
Bridge instrumentation
The temperature changes in one footbridge were moni-
tored with two thermocouples: one inserted in the center of
the deck and another in the center of the supporting (edge)
beam. Figure 6 provides the results from the two thermo-
couples. The temperature reached approximately 53°C
(127°F) in the rst days after casting, followed by a gradual
drop to laboratory temperature. After curing at laboratory
temperature (around 23°C [73°F]) for 28 days, the footbridges
were transferred to the eld sites, where the temperature
dropped below zero, as shown by the sudden drop in the
temperature curve. Some nights, the temperature fell to
–30°C (–22°F).
A vibrating wire gauge was inserted at the center of the
instrumented bridge deck to measure deformation due to
shrinkage (Fig. 6). A strain of about 430 µm/m was measured
at the end of laboratory curing, followed by a sudden increase
in the deformation at the eld site due to the temperature
changes and removal of the plastic sheeting (the strains
resulted from temperature change and additional drying
shrinkage). The total strain was as much as 1200 µm/m on
some days. After deducting thermal expansion, the isothermal
strain was about 800 µm/m.
Summary
A new type of UHPC has been developed using recycled
glass, creating UHPGC. The new material exhibited
excellent workability and rheological properties due to
the zero absorption of the glass particles and optimized
packing density for the entire material matrix. The
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www.concreteinternational.com | Ci | MARCH 2015 59
Arezki Tagnit-Hamou, FACI, is a Professor
in the Civil Engineering Department at the
Université de Sherbrooke, QC, Canada.
He is also the Head of the cement and
concrete group and industrial chair holder
on valorization of glass in materials. He is
a member of ACI Committees 130,
Sustainability of Concrete, and 555,
Concrete with Recycled Materials.
ACI and CRIB member Nancy Soliman is
a PhD candidate at the Department of
Civil Engineering, Université de Sher-
brooke. Her research interests include
development of NDT, ultra-high-perfor-
mance concrete, microstructure of
cement and concrete, and sustainable
development.
Ahmed F. Omran is a Postdoctoral Fellow
at the Department of Civil Engineering,
Université de Sherbrooke, and Assistant
Professor at University of Minuya, Menua,
Egypt. He received his BS and MS in civil
engineering from the University of Minuya,
and his PhD degree from Université de
Sherbrooke. He is a member of RILEM
Technical Committee 233-FPC.
ACI member Mohammed T. Mousa is a
PhD student in the Department of Civil
Engineering, Université de Sherbrooke,
Sherbrooke QC, Canada, and a civil
engineer at Helwan University, Cairo,
Egypt. He received his BSc in civil
engineering from Benha University, and
his MSc and PhD in civil engineering from
Helwan University.
Nicolas Gauvreau, is the Co-Founder,
Vice President, and Technical Director of
Bétons Génial, Inc., Saint Jean-sur-Richelieu,
QC, Canada. He has more than 20 years
of experience in prefabricated concrete
and molds. His company specializes in
unique and innovative manufacturing
processes.
MFrancine Provencher is an architect
member of L’Ordre des architectes du
Québec (OAQ) since 1984 and has been
credentialed as a LEED AP since 2004
with BD+C speciality. She is Director of
Planning and Sustainability Department at
the Building Services of Université de
Sherbrooke since 1993.
mechanical properties were found to be excellent and
comparable to conventional UHPC.
The construction of two UHPGC footbridges at the
University of Sherbrooke shows the potential for the material
to be used in future projects. UHPGC will produce highly
energy efcient, environmentally friendly, affordable, and
resilient structures.
Acknowledgments
This research was funded by the SAQ Industrial Chair on Valorization of
Glass in Materials and the authors gratefully acknowledge this support.
The authors would also like to acknowledge the support of the University
of Sherbrooke in conducting this project.
References
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with High Ductility and 200-800 MPa Compressive Strength,”
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Concrete Institute, Farmington Hills, MI, 1994, pp. 507-518.
2. Richard, P., and Cheyrezy, M., “Composition of Reactive Powder
Concretes,” Cement and Concrete Research, V. 25, No. 7, Oct. 1995,
pp. 1501-1511.
3. Roux, N.; Andrade, C.; and Sanjuan, M., “Experimental Study of
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Concrete: A Symposium Honoring Dr. Edward G. Nawy, SP-225,
American Concrete Institute, Farmington Hills, MI, 2005, pp. 51-77.
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Tomorrow,” Cement and Concrete Research, V. 30, No. 9, Sept. 2000,
pp. 1349-1359.
6. Tagnit-Hamou, A., and Soliman, N., “Ultra-High Performance
Glass Concrete and Method for Producing Same,” U.S. Patent Applica-
tion No. 61/806,083, accepted March 2014.
7. de Larrard, F., Concrete Mixture Proportioning: A Scientic
Approach, CRC Press, 1999, 448 pp.
8. Brameshuber, W., and Uebachs, S., “Practical Experience with the
Application of Self-Compacting Concrete in Germany,” Proceedings of
the Second International Symposium on Self-Compacting Concrete,
Tokyo, Japan, 2001, pp. 687-696.
9. EFNARC, “Specication and Guidelines for Self-Compacting
Concrete,” Feb. 2002, (http://www.efnarc.org), pp. 32.
10. “Introduction to Ductal® – Frequently Asked Questions,” VSL
Proprietary Limited, 2003. (http://www.ductal.com/Introduction%20
to%20Ductal.pdf)
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P.-C., “Mechanical Properties and Durability of Two Industrial Reactive
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pp. 286-290.
Note: Additional information on the ASTM and CSA standards
discussed in this article can be found at www.astm.org and
www.csagroup.org, respectively.
Selected for reader interest by the editors.
... The developed UHPGC using G was used in the construction of two footbridges (Fig. 6) at the University of Sherbrooke showing a potential for the UHPGC to be used in future large-scale projects [13,14]. The G used in the UHPGC mix design for constructing the bridges had maximum particle size of 100 µm and specific gravity of 2.60. ...
... Compressive strength undertaken on core samplescompared to 28 and 91-days results following casting[14] ...
Article
Full-text available
Ground-glass pozzolan (G) obtained by grinding the mixed-waste glass to same fineness of cement can act as a supplementary-cementitious material (SCM), given that it is an amorphous and a pozzolanic material. The G showed promising performances in different concrete types such as conventional concrete (CC), high-performance concrete (HPC), and ultra-high performance concrete (UHPC). The current paper reports on the characteristics and performance of G in these concrete types. The use of G provides several advantages (technological, economical, and environmental). It reduces the production cost of concrete and decrease the carbon footprint of a traditional concrete structures. The rheology of fresh concrete can be improved due to the replacement of cement by non-absorptive glass particles. Strength and rigidity improvements in the concrete containing G are due to the fact that glass particles act as inclusions having a very high strength and elastic modulus that have a strengthening effect on the overall hardened matrix.
... below 0.20), the degree of hydration of cement is limited to about 30% after 28 days [2,3]. Thus, a major part of anhydrous cement clinker particles acts as filler, which can be potentially replaced by cheaper, less resource-intensive SCMs such as fly ash, slag, limestone, natural pozzolans, conventional quartz sand or post-consumption glass powder [2,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. If mechanical properties are not compromised, such replacements can have strong economical and environmental potentials for construction using UHPC [7,11]. ...
... Following the conclusions of this work and previous works by Soliman and co-workers [5,[18][19][20]66], future research includes the optimization of cement fineness and its dosage relative to solid inclusions, with the aim to increase its degree of hydration while maintaining adequate fresh properties and similar repartition of hydrates and inclusions in the hardened microstructure. ...
Article
The development of Ultra-High Performance Concrete (UHPC) opened new research directions for enhancing the architectural design, sustainability and serviceability of concrete structures. However, the costs and resource intensiveness trigger the need for innovative UHPC mix design incorporating alternative materials, such as post-consumption Glass Powder (GP). This works aims at disclosing the microstructure features of UHPGC, in which the constituents can be partially replaced by different fineness of GP without impacting the long-term strengths. By using the latest NI-QEDS technique (coupling NanoIndentation and Quantitative Energy-Dispersive Spectroscopy), as well as image analysis applied to EDS chemical mappings, it was possible to investigate mechanical properties of the microstructure constituents and their volume fractions. A conventional UHPC microstructure was compared to a similar system with 30% replacement of cement by GP and to another system with 50% replacement of silica fume by Fine GP (FGP). The results showed the key role of GP anhydrous particles contributing to the rigid skeleton of anhydrous inclusions, as well as their bond quality with the surrounding cement paste. The reduction of cement and silica fume was thus possible without impairing the micromechanical properties of the hydrates, by improving the particle packing density in the hardened state. As major conclusion, replacing cement and silica fume with GP and FGP without impairing both micro-scale and macro-scale mechanical properties provides a promising means to reduce the environmental footprint of current UHPC mix design.
... The developed UHPGC using G was used in the construction of two footbridges (Fig. 6) at the University of Sherbrooke showing a potential for the UHPGC to be used in future large-scale projects [13,14]. The G used in the UHPGC mix design for constructing the bridges had maximum particle size of 100 µm and specific gravity of 2.60. ...
... Compressive strength undertaken on core samplescompared to 28 and 91-days results following casting[14] ...
Article
Full-text available
Ground-glass pozzolan (G) obtained by grinding the mixed-waste glass to same fineness of cement can act as a supplementary-cementitious material (SCM), given that it is an amorphous and a pozzolanic material. The G showed promising performances in different concrete types such as conventional concrete (CC), high-performance concrete (HPC), and ultra-high performance concrete (UHPC). The current paper reports on the characteristics and performance of G in these concrete types. The use of G provides several advantages (technological, economical, and environmental). It reduces the production cost of concrete and decrease the carbon footprint of a traditional concrete structures. The rheology of fresh concrete can be improved due to the replacement of cement by non-absorptive glass particles. Strength and rigidity improvements in the concrete containing G are due to the fact that glass particles act as inclusions having a very high strength and elastic modulus that have a strengthening effect on the overall hardened matrix.
... This approach helps reduce costs by reusing what was considered a wastematerial all while saving time and reducing carbon emissions from the production of new aggregates 78 . As studies show, others replace parts of the highly pollutant Portland cement with recycled or repurposed products such as fly ash or micronized glass 79 . The Ultra-High-Performance Glass Concrete (UHPGC) for example, uses micronized glass powder to create an ecological highperformance mix, giving concrete improved physical properties that help reduce heat island effects 80 . ...
Conference Paper
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The P21 Framework for 21st Century Learning identifies collaboration as a key educational outcome as it prepares students for the real world problem solving and enhance their prospects for employment. Therefore, group assessments are becoming a commonplace in higher education, mainly to promote collaborative working environment and peer learning amongst students. In addition, group assessments are considered as an effective assessment strategy to manage large classes as it reduces the marking burden on academics. Despite the benefits, students resent group work particularly when a common group mark is awarded when there is a varying level of inputs from the members of the group. Especially, non- engaging students could possibly attain good grades without contributing to the group work or with minimal contribution. This problem of “free riders” disadvantages and discourages engaging students. There is a plethora of peer assessment methods used by academics to assess group works. However, there is a dearth of studies which explores why a particular method is preferred and the difference it makes on the final grades of students. Therefore, this paper explores different methods of peer assessments by reviewing recent literature and expands into comparing the final grades derived from two different methods of peer assessments adopted in the same module to study the end results. Finally, the correlation between the final individual grades and the peer marks given was unpacked which allows academics to make an informed decision.
... From these, 701 observations were reported by previous studies, while 230 were taken from our own experimental works. For further information about the database, references [6,7,30,31,36,50,51, can be consulted for the 701 observations from scientific literature, while references [2,3,9,26,52,53,61] can be consulted for more information about our own experimental works. ...
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With advances in building materials research, new materials more suitable for specific applications due to their superior durability and mechanical properties are emerging to meet the requirements of infrastructure construction and maintenance. In this sense, ultra-high-performance concrete (UHPC) is considered one of the most promising materials for concrete construction. However, a traditional UHPC mixture contains large amounts of cement, silica fume, superplasticizer, and other expensive and high carbon footprint components. Hence, several researchers have focused on developing alternative UHPC dosages using locally available materials, including several mineral admixtures, to obtain a more affordable and sustainable UHPC. Therefore, deep knowledge about the relationships between the UHPC dosage and its resulting properties could help to improve these developments. However, these relationships are nonlinear and complex. This paper aims to address this gap by using a random forest model trained with a 931 UHPC mixture collection with 17 input variables and a unique response, namely the UHPC compressive strength. After adjusting a regression model, different tools, such as input variable importance analysis and partial dependence plots, were used to assess the nonlinear relationships between the dosage of UHPC and its resulting compressive strength. In most cases, a proper alignment was observed when the findings provided by these analyses were contrasted with the results provided by other researchers. The results indicated that the inputs with the highest significance on UHPC compressive strength are those related to water content, the packing density, and the quartz powder and superplasticizer dosages, followed by the cement content. Furthermore, mineral admixtures with high amorphous SiO2 content, such as RHA and SF, presented a relevant contribution to the compressive strength, while the other admixtures would seem to have a more modest contribution to it. Finally, it is also worth noting that the machine learning model created might help to create novel UHPC dosages by decreasing the duration and expenses of the experimental campaign by permitting the pre-selection of those components with a superior model response.
... This approach helps reduce costs by reusing what was considered a wastematerial all while saving time and reducing carbon emissions from the production of new aggregates 78 . As studies show, others replace parts of the highly pollutant Portland cement with recycled or repurposed products such as fly ash or micronized glass 79 . The Ultra-High-Performance Glass Concrete (UHPGC) for example, uses micronized glass powder to create an ecological highperformance mix, giving concrete improved physical properties that help reduce heat island effects 80 . ...
Conference Paper
Full-text available
Humans are fundamentally designers – humans create artifacts, shelters, communities, and landscapes. Design is a complicated process and involves conceiving, representing, and executing constructions across a wide range of scales. Various methods and approaches to design have been theorized over the last several decades resulting in a wide range of design process diagrams and strategies. The task outlined here was to develop a tool to help structure the ongoing decision-making that is part of any design process, to present a comprehensive range of topics that designers should consider as they evolve a scheme. To this end we are introducing the Diagram as a working tool that frames a broad range of spatial, ecological, cultural, and material factors; it is designed to play a key role as a teaching tool primarily within design studios.
... The high cost of UHPC is generally recognized as a challenge, whereas it may be offset by optimized structural configurations, superior performance, and extended service life. 5,6 Accordingly, numerous projects were conducted to demonstrate the feasibility of UHPC for structural applications. 7,8 While the closure of precast bridge girders has been a representative usage of UHPC, 9 transportation agencies recently adopted this state-of-the-art material for constructing superstructure members. ...
Article
This paper presents the characteristics of a cost-effective ultra-high-performance concrete (UHPC) made of locally available constituents. The implications of steel and synthetic fibers on the shrinkage, maturity, and chloride permeability of the sili-ca-based concrete are of interest. To implement assorted standard test methods, UHPC cylinders and prisms are cast and instru-mented. The interaction between the fibers and cement paste affects the shrinkage of UHPC. Owing to the absence of coarse aggregate, the applicability of existing shrinkage models for ordinary concrete is not satisfactory; accordingly, a new expression is proposed. The early-age hydration of cement (less than 1 day) generates thermal energy, depending upon fiber type, which raises the temperature of the concrete. The load-carrying capacity of UHPC mixed with steel fibers is higher than that of UHPC with synthetic fibers. The maturity of UHPC is contingent upon fiber configuration; specifically , plain and steel-fiber-mixed UHPC cylinders show a superior early-age strength gain to those with synthetic fibers. For the Nurse-Saul and the Arrhenius maturity approaches (time temperature factor and equivalent age, respectively), regression equations are fitted. The flow of electric current and the resistivity of UHPC are favorable due to the densely formulated grain structure, leading to the improvement of durability when used for structural application. The diffusion coefficient of UHPC increases as the mixed fibers create interfacial gaps in the cement paste.
... The steel fiber has a length of 12.7 mm and a diameter of 0.2 mm, an aspect ratio of fiber-to-length of about 64; (ii) the second one is an UHPFRC#2 reinforced with 2% volume content of polyvinyl alcohol fibers, which is commercially available under the name of "Durabex" by Bétons Génial. Notably, the latter UHPFRC has an ecological value because it recycles glass powder in the mix design [40]. The compressive strength was determined by standard tests on a cylindrical sample of 200 mm height and 100 mm diameter according to standard ASTM C39M-18 [41]. ...
Article
Different kinds of ductile connectors have been lately developed for enhancing the structural ductility of Timber-Concrete Composite (TCC) structures. In particular, ductile notch connections can be designed by favoring the local compression failure of wood fibers. This work aims at further developing economic and ductile notch connector by considering different floor systems made of Glulam Laminated Timber (GLT) beam or Cross Laminated Timber (GLT or CLT) slab connected with a High Performance Concrete (HPC) slab or a Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) slab. Firstly, the geometry of the notch connector was suitably designed for favoring a ductile hierarchy of collapse modes. Then, a wide campaign of push-out tests was carried out to characterize the shear behaviour of 14 connection configurations by varying the notch geometry, the concrete type and the possible presence of acoustic insulation. Finally, based on the experimentally identified connection shear law, an example of design is presented for a TCC slab of 9 m span. The insulation layer was found to reduce the connection stiffness, but to increases the structural stiffness thanks to the enhanced lever arm of the composite action. For plastically designed TCC structures, the connection ductility allows increasing the structural ductility for both GLT-(U)HPC and for CLT-(U)UPC floor systems.
... In addition, GP was shown to increase the strength capacity of reinforced concrete columns. Recently, GP of various particle-size distributions was used to develop a new ultra-high-strength concrete with compressive strength exceeding 250 MPa (Tagnit-Hamou et al., 2015). ...
Article
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Synopsis: One of the breakthroughs in concrete technology is ultra-high-performance concrete with a steel like compressive strength of up to 250 N/mm 2 and a remarkable increase in durability compared even with high-performance concrete. In combination with steel fibres it is now possible to design sustainable filigree, lightweight concrete constructions with or even without additional reinforcement. Wide span girders, bridges, shells and high rise towers are ideal applications widening the range of concrete applications by far. In addition e.g. to some pedestrian bridges heavily trafficked road bridges has been build in France and in the Netherlands. Bridges are already under construction in Germany as well. A wide range of new concrete formulations has been developed to cover an increasing number of applications. Technical recommendations have recently been published in France and in Germany covering material as well as design aspects. The paper will report on the state of research and application of UHPC in Europe, on material and design aspects of UHPC and will present the state-of-the-art based on an International Symposium on UHPC held in Kassel in 2004.
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The durability of reactive powder concretes (RPC) has been defined by measuring porosity, air permeability, water absorption, diffusion, and migration of chloride ions, accelerated carbonation, resistance to reinforcement corrosion, resistivity, and resistance to mechanical abrasion. Results were compared with the characteristics of a grade 30 MPa concrete with a low cement content and a grade 80 MPa very high performance concrete. The RPC displays excellent granular compactness, and its low water content helps reduce porosity. This results in an excellent resistance to the penetration of aggressive agents with respect to the reference concretes, and structures built with RPC are expected to significantly outlast those built with ordinary concrete.
Article
Two reactive powder concretes (RPC) were produced on an industrial scale at the Université de Sherbrooke and in a nearby precast plant. A 2.6 m3 mix was prepared in a ready mix truck while a 1.35 m3 mix was prepared in the central mixer of the precast plant. The ready mix RPC was sampled before and after the addition of steel fibers while the one produced at the precast plant was sampled only at the end of the mixing process. These RPCs were tested for compressive strength, modulus of elasticity, freezing and thawing cycling resistance, scaling resistance to deicing salts, and resistance to chloride ion penetration. Large samples were also cast allowing core samples to be taken. The results show that a 200 MPa compressive strength could be achieved in both cases: after curing in hot water at 90 deg C or in the low pressure steam chambers at the precast plant. Confinement of the RPC in a steel tube greatly increases its compressive strength and its ductility. The two mixes were found to he freeze-thaw resistant and presented a very low mass loss under the scaling test. Chloride ion permeability was below 10 Coulombs even for the specimens containing steel fibers; this extremely low value translates to the quasi-impermeability of the two RPCs.
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Concrete, the most widely used construction material, is evolving. Modern concrete is more than simply a mixture of cement, water, and aggregates; modern concrete contains more and more often mineral components, chemical admixtures, fibres, etc. Of course the utility market will stay the major market of concrete but niche markets implying the use of “à la carte” smart concretes will also develop. The development of these smart concretes results from the emergence of a new science of concrete, a new science of admixtures and the use of sophisticated scientific apparatus to observe concrete microstructure and even nanostructure.
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Development of an ultra-high strength ductile concrete designated RPC (Reactive Powder Concrete), was made possible by the application of a certain number of basic principles relating to the composition, mixing and post-set heat curing of the concrete.RPC 200, which can be used under job site conditions similar to those for conventional high performance concretes, can be used in the construction of prestressed structures incorporating no passive reinforcement. RPC800 is suitable for precasting, and can achieve compressive strength values exceeding 600MPa. A value of 810MPa has been obtained with a mixture incorporating steel aggregate.
Ultra-High Performance Glass Concrete and Method for Producing Same Concrete Mixture Proportioning: A Scientific Approach Practical Experience with the Application of Self-Compacting Concrete in Germany
  • A Tagnit-Hamou
  • N F W Soliman
  • S Uebachs
Tagnit-Hamou, A., and Soliman, N., " Ultra-High Performance Glass Concrete and Method for Producing Same, " U.S. Patent Application No. 61/806,083, accepted March 2014. 7. de Larrard, F., Concrete Mixture Proportioning: A Scientific Approach, CRC Press, 1999, 448 pp. 8. Brameshuber, W., and Uebachs, S., " Practical Experience with the Application of Self-Compacting Concrete in Germany, " Proceedings of the Second International Symposium on Self-Compacting Concrete, Tokyo, Japan, 2001, pp. 687-696.
Specification and Guidelines for Self-Compacting Concrete Introduction to Ductal ® – Frequently Asked Questions
EFNARC, " Specification and Guidelines for Self-Compacting Concrete, " Feb. 2002, (http://www.efnarc.org), pp. 32. 10. " Introduction to Ductal ® – Frequently Asked Questions, " VSL Proprietary Limited, 2003. (http://www.ductal.com/Introduction%20 to%20Ductal.pdf)