Frgc products for_undergound_infrastructure
An investigation was conduced to achieve concrete of higher strength using crushed brick as aggregate and study the mechanical properties. It was found that higher strength concrete (cf= 4500 to 6600 psi1) with brick aggregate is achievable whose strength is much higher than the parent uncrushed brick. Test results show that the compressive strength of brick aggregate concrete can be increased by decreasing its water-cement ratio and using admixture whenever necessary for workability. The compressive strength as well as the tensile strength and the modulus of elasticity of the concrete were studied. The cylinder strength is found about 90% of the cube strength. The ACI Code relations for determining the modulus of rupture was found to highly underestimate the test values., whereas the code suggested expression for elastic modulus gives much higher values than the experimental ones for brick aggregate concrete. Relations were proposed to estimate the modulus of rupture and the modulus of elasti
"Reliability assessment of braided FRP reinforcement for concrete structures"...TRUSS ITN
Abstract: In recent years the long term durability of reinforced concrete structures has become a major concern. The effect of harsh loading conditions and aggressive environmental factors can lead to corrosion of reinforcing steel in civil engineering applications. This in turn leads to undesired repairs, additional costs and shorter service lives. Advanced composite materials, such as Basalt Fibre Reinforced Polymer (BFRP), have the capacity to significantly address this problem. These materials have enhanced physical properties such as higher mechanical and corrosion resistance, and have the potential to replace traditional steel rebars as tension reinforcement in concrete. There are however limitations that prevent their use on a larger scale, and lack of ductility is the most significant. Braiding techniques could provide the required performance benefits related to the additional ductility and flexibility needed, as well as enhancing the bond between FRP and concrete. If this is achieved, it has the potential to prevent a brittle failure and successfully meet strength, reliability and cost demands. This study focuses on the basics of materials characterization and reliability analysis of internal BFRP reinforcement for concrete structures towards design optimization for structural reliability over their service life.
"Reliability assessment of braided FRP reinforcement for concrete structures"...TRUSS ITN
Abstract: In recent years the long term durability of reinforced concrete structures has become a major concern. The effect of harsh loading conditions and aggressive environmental factors can lead to corrosion of reinforcing steel in civil engineering applications. This in turn leads to undesired repairs, additional costs and shorter service lives. Advanced composite materials, such as Basalt Fibre Reinforced Polymer (BFRP), have the capacity to significantly address this problem. These materials have enhanced physical properties such as higher mechanical and corrosion resistance, and have the potential to replace traditional steel rebars as tension reinforcement in concrete. There are however limitations that prevent their use on a larger scale, and lack of ductility is the most significant. Braiding techniques could provide the required performance benefits related to the additional ductility and flexibility needed, as well as enhancing the bond between FRP and concrete. If this is achieved, it has the potential to prevent a brittle failure and successfully meet strength, reliability and cost demands. This study focuses on the basics of materials characterization and reliability analysis of internal BFRP reinforcement for concrete structures towards design optimization for structural reliability over their service life.
Collaboration with UAF School of Management:
Associate professor Jim Collins, UAF School of Management Director of
Entrepreneurship, has taken an interest in this project and begun involving some of his
students in working on the economic feasibility and business-planning aspects. This
project provides students with an excellent opportunity to leverage their academic
study and exercises into real-world results. CCHRC is pleased and grateful to have the
opportunity to collaborate with these students and for Dr. Collins’ interest and
mentorship.
Collaboration with Small Businesses in Fairbanks & North Pole:
A growing number of local cement-related business owners and managers are
expressing interest in participating directly in CCHRC’s efforts to develop the commercial
applications of geopolymer cements and concretes. These businesses presently include
Stonecastle Masonry, Fairweather Masonry, MAPPA Test Lab, and Fairbanks Precast &
Rebar.
One of the top 20 in the 2010 Arctic Innovation Competition:
Out of more than 200 entries in the UAF School of Management 2010 Arctic Innovation
Competition, CCHRC’s presentation (given by Ty Keltner) on the potential for local
geopolymer development was selected as one of the top 20. The final four projects
were notably further along in the process of establishing a specific business. CCHRC’s
involvement in the competition helped establish connections with individuals
contributing suggestions and expressing interest in working with us in the future. These
included Jim Collins in the School of Management and Shiva Hullavarad in the Advanced
Materials Group of the UAF Institute of Northern Engineering.
Collection and organization of 2.5GB of relevant literature:
CCHRC staff have collected, organized and partially reviewed more than 2.5 GB of text
on the alternatives to portland cement. That currently amounts to 2,049 files in 161
folders and seven mind-maps, including over 600 research papers. Plus seven text books
on geopolymer cements. Although it is outside the scope of this project, the
organization of this information has been done in a manner which will facilitate
references, abstracts and CCHRC’s notes being made publically available on the Internet
without copyright infringement. It is our hope that this extensive and on-going literature
Halcrow low carbon_concrete_sydney_2009
stone, clay and other minerals. Quarrying of these raw
materials is also causes environmental degradation. To
produce 1 ton of cement, about 1.6 tons of raw materials
are required and the time taken to form the lime stone is
much longer than the rate at which humans use it.
On the other side the demand of concrete is
increasing day by day for its ease of preparing and
fabricating in all sorts of convenient shapes. So to
overcome this problem, the concrete to be used should be
environmental friendly. To produce environmental friendly
concrete, we have to replace the cement with the industrial
by products such as fly-ash, GGBS (Ground granulated
blast furnace slag) etc. In this respect, the new technology
geo-polymer concrete is a promising technique. The term
geopolymer was first coined by Davidovits in 1978 to
represent a broad range of materials characterized by
chains or networks of inorganic molecules. [Geo-polymer
institute][6]. Geopolymers are chains or networks of
mineral molecules linked with co-valent bonds.
Geopolymer is produced by a polymeric reaction of
alkaline liquid with source material of geological origin or
by product material such as GGBS. Geo-polymers have the
chemical composition similar to Zeolites but they can be
formed an amorphous structure. For the binding of
materials the silica and alumina present in the source
material are induced by alkaline activators. [4]. The most
common alkaline liquid used in the geo-polymerization is
the combination of Sodium hydroxide/ Potassium
hydroxide and Sodium silicate/ Potassium silicate. This
combination increases the rate of reaction. Among 15
Alumino-silicate minerals, all the Al-Si minerals are more
soluble in NaOH solution than in KoH solution [5]. Ground
granulated blast furnace slag (GGBS) is a by-product from
the blast-furnaces used to make iron. During the process,
slag was formed and it is then dried and ground to a fine
powder.
The compressive strength, flexural strength, and split tensile strength of Reactive Powder concrete are all
investigated in this study (RPC). The lack of ductility in ordinary concrete is considered a key concern in this
research. RPC is being explored as a solution for the aforementioned challenge as the building industry's
technology advances. Cement, sand, water, admixture, and superplasticizer are all included in the RPC. The
reactive powder concrete mixture is made by changing the percentages of super plasticizer (2%, 3% and 4%),
silica fumes (10%, 20%, and 30%), while maintaining the dose of quartz powder constant. At the outset of this
study, compressive strength, flexural strength, and split tensile strength targets of 140-160Mpa, 20-30Mpa, and
15-20Mpa were set. However, due to a change in material qualities that were locally accessible and of low
quality, the results produced after the investigation were unsatisfactory to get the findings, the RPC was mixed,
cast, cured, and tested in the concrete laboratory using three different mix proportions.
150mmX150mmX150mm cube, 500mmX100mmX100mm beam, and 150mm diameter and 300mm height
cylinder are all made of fresh concrete. The casted RPC is then cured in a water tank at room temperature for 7,
14, and 28 days before being oven dried for 24 hours at 60 degrees Celsius. The final results were documented
and discussed, as well as conclusions and recommendations based on the findings.
Effect of Steel Fiber on Alkali activated Fly Ash ConcreteIJERA Editor
Concrete is the world’s most important Construction material so the demand of cement is increases. The
production of cement is highly energy intensive & the production on one ton of cement liberates about one ton
of CO2 to atmosphere. The contribution of cement industry to the greenhouse gas emission is estimated to be
about 70% of the total green gas emission. Also it consumes large amount of natural resources. Hence it is
essential to find alternative to cement. Geopolymer concrete is an innovative material in which the binder is
produced but the reaction of an alkaline liquid with a source material that is rich in silica alumina.
The present work deals with the result of the experimental investigation carried out on geopolymer concrete
using steel fiber. The study analyses the effect of steel on compressive strength. Geopolymer concrete mixes
were prepared using low calcium fly ash & activated by alkaline solution. (NaOH & Na2SiO3) with alkaline
liquid to fly ash ratio of 0.35 Alkaline solution. Used for present study combination of sodium hydroxide &
sodium silicate with ratio 2.5. The mix was designed for molarity of 16M & grade chosen for investigation was
M30. Hooked end steel fiber . All tests were conducted according to IS-code procedure. The result for each
variation are tabulated & discussed in details & some important conclusions are made.
Effect of mineral admixtures on characteristics of high strength concreteeSAT Journals
Abstract
There is great need to conserve all the natural resources. The various steps to be adopted in the direction that includes minimization of production of energy consuming materials and heavy utilization of industrial by-products. High strength concrete can be produce using such materials like fly ash, slag and silica fumes. In many countries, these materials are already used in manufacturing of concrete. Some of these material can be used as replacement for cement. Ultimately it results in the reduction of the cost manufacturing of concrete and reduces environmental pollution. To study the effect of mineral admixtures such as fly ash, slag and silica fume on mechanical properties of high strength concrete under the uniaxial compression and split tensile, experimental studies have been conducted. The cement was replaced by 5%, 10%, 15% and 20% with fly ash and slag respectively. The compressive strength and split tensile test were conducted on concrete specimen with different percentages of fly ash and slag at age of 7 days, 28 days and 56 days. This study shows that materials used in this experiment are suitable for HSC.
Keywords: environmental pollution, fly ash, slag and silica fumes
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
Welocme to ViralQR, your best QR code generator.ViralQR
Welcome to ViralQR, your best QR code generator available on the market!
At ViralQR, we design static and dynamic QR codes. Our mission is to make business operations easier and customer engagement more powerful through the use of QR technology. Be it a small-scale business or a huge enterprise, our easy-to-use platform provides multiple choices that can be tailored according to your company's branding and marketing strategies.
Our Vision
We are here to make the process of creating QR codes easy and smooth, thus enhancing customer interaction and making business more fluid. We very strongly believe in the ability of QR codes to change the world for businesses in their interaction with customers and are set on making that technology accessible and usable far and wide.
Our Achievements
Ever since its inception, we have successfully served many clients by offering QR codes in their marketing, service delivery, and collection of feedback across various industries. Our platform has been recognized for its ease of use and amazing features, which helped a business to make QR codes.
Our Services
At ViralQR, here is a comprehensive suite of services that caters to your very needs:
Static QR Codes: Create free static QR codes. These QR codes are able to store significant information such as URLs, vCards, plain text, emails and SMS, Wi-Fi credentials, and Bitcoin addresses.
Dynamic QR codes: These also have all the advanced features but are subscription-based. They can directly link to PDF files, images, micro-landing pages, social accounts, review forms, business pages, and applications. In addition, they can be branded with CTAs, frames, patterns, colors, and logos to enhance your branding.
Pricing and Packages
Additionally, there is a 14-day free offer to ViralQR, which is an exceptional opportunity for new users to take a feel of this platform. One can easily subscribe from there and experience the full dynamic of using QR codes. The subscription plans are not only meant for business; they are priced very flexibly so that literally every business could afford to benefit from our service.
Why choose us?
ViralQR will provide services for marketing, advertising, catering, retail, and the like. The QR codes can be posted on fliers, packaging, merchandise, and banners, as well as to substitute for cash and cards in a restaurant or coffee shop. With QR codes integrated into your business, improve customer engagement and streamline operations.
Comprehensive Analytics
Subscribers of ViralQR receive detailed analytics and tracking tools in light of having a view of the core values of QR code performance. Our analytics dashboard shows aggregate views and unique views, as well as detailed information about each impression, including time, device, browser, and estimated location by city and country.
So, thank you for choosing ViralQR; we have an offer of nothing but the best in terms of QR code services to meet business diversity!
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
In questo evento online gratuito, organizzato dalla Community Italiana di UiPath, potrai esplorare le nuove funzionalità di Autopilot, il tool che integra l'Intelligenza Artificiale nei processi di sviluppo e utilizzo delle Automazioni.
📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
Autopilot per Studio Web
Autopilot per Studio
Autopilot per Apps
Clipboard AI
GenAI applicata alla Document Understanding
👨🏫👨💻 Speakers:
Stefano Negro, UiPath MVPx3, RPA Tech Lead @ BSP Consultant
Flavio Martinelli, UiPath MVP 2023, Technical Account Manager @UiPath
Andrei Tasca, RPA Solutions Team Lead @NTT Data
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
The Art of the Pitch: WordPress Relationships and Sales
Frgc products for_undergound_infrastructure
1. Fibre reinforced geopolymer concrete products for
underground infrastructure
Don Wimpenny
1
, Peter Duxson
2
, Tony Cooper
3
John Provis
4
, Robert Zeuschner
5
1 – Head of Materials & Asset Engineering, Halcrow Pacific Pty Ltd
2 - Chief Operating Officer, Zeobond Pty Ltd,
3 – General Manager Australia , Elastoplastic Concrete Pty Ltd,
4 - Senior Research Fellow, Department of Chemical & Biomolecular Engineering, University of
Melbourne
5 – General Manager Southern Region, Humes
TM
, Holcim (Australia) Pty Ltd
Synopsis: This paper presents the initial findings of a 3-year project to develop Fibre Reinforced
Geopolymer Concrete (FRGC) products for underground infrastructure. The work is funded by the
Victorian Science Agenda Investment Fund and a consortium of five organisations. By combining
synthetic fibre reinforcement and geopolymer technology, it is possible to remove Portland cement and
steel reinforcement from structural concrete to produce a new generation of structural concrete with
potential benefits of improved durability and reduced embodied carbon content.
The work involves laboratory studies, long-term exposure tests, production of prototype tunnel segments
and a life cycle assessment of embodied carbon for the products. The properties of the fresh and
hardened FRGC have been investigated, including workability, strength and durability. The latter has
included standard parameters, such as apparent volume of permeable voids (AVPV), as wells as chloride
migration testing and exposure to acid and sulphate solutions.
Mix designs utilising different fibre dosages and geopolymer binders have been assessed, together with
standard and accelerated curing regimes. The objective of the testing has been to provide information on
the essential engineering characteristics of the material using a typical specification as the basis for
compliance. Control mixes using Portland cement and 40kg/m
3
of steel fibres were also tested for
comparison purposes.
The test results show the FRGC mixes outperform the Portland cement based control mixes in terms of
strength, shrinkage and durability, and at the same time can reduce carbon emissions by approximately
70%.
Keywords: strength, chloride diffusion, synthetic fibres, flexural, geopolymer, carbon emissions.
1. Introduction
Concrete makes a substantial contribution to society, from its use in large infrastructure projects through
to public buildings and social housing schemes. Use of concrete in construction is also a major contributor
to greenhouse gases, reportedly generating more than 5% of worldwide carbon dioxide (CO2) emissions,
over three-quarters deriving from the Portland cement binder. Approximately half the CO2 emissions from
Portland cement are associated with energy used in the heating and grinding processes. The remaining
emissions derive from the chemical de-carbonation of the limestone. The cement industry has made
considerable improvements in energy efficiency and use of alternative fuel sources. However, if worldwide
emissions targets are to be met, some radical changes are required to further reduce the CO2 emissions
derived from the use of concrete.
A study carried out on behalf of the UK Environment Agency has identified concrete using geopolymer
binders as the most promising low carbon alternative to conventional concrete (1).
In reinforced concrete, the second highest source of carbon emissions is the steel reinforcement. Recent
developments in the production and use of synthetic fibres position these materials as an alternative to
steel reinforcing bar and steel fibres, with benefits of lower carbon emissions as well as the possibility of
enhanced durability (2).
2. This paper presents the initial findings of a 3-year project to develop Fibre Reinforced Geopolymer
Concrete (FRGC) precast products for underground infrastructure. By combining synthetic fibre
reinforcement and geopolymer technology, it is possible to remove Portland cement and steel
reinforcement from structural concrete to produce a new generation of structural concrete with potential
benefits of improved durability and reduced embodied carbon content.
The work is funded by the Victoria’s Science Agenda Investment Fund and a consortium of five
organisations. The consortium members are able to provide all the facets required to successfully develop
FRGC, from design and specification through to testing and production:
a) Design and specification of fibre reinforced concrete - Halcrow
b) Fibre technology – EPC
c) Geopolymer technology – Zeobond
d) Testing – University of Melbourne
e) Precast production - Humes.
The grant funded portion of the project is due to be completed in mid-2012.
2. Scope and objectives
The introduction of new products in the construction industry is controlled by the understandably
conservative nature of the engineering profession and the need to meet existing industry specifications.
Some of the issues relating to adoption of geopolymer and fibre technology are indicated in Table 1. In
order to address these issues, this project pre-empts the normal approvals process by testing the FRGC
products against the requirements of a typical performance specification. In addition, the project aims to
develop guidance on structural and durability design and produce prototype products.
Table 1. Key issues to address in the adoption of FRGC technology.
Geopolymer Synthetic fibres
Absence of structural design parameters
Practical constraints (e.g. controlling workability, setting
time and strength development)
Uncertainty over long-term performance (eg permeability
and diffusion properties and acid resistance)
Absence of structural design parameters
Uncertainty over long-term performance (eg creep)
Urgent need to identify appropriate test methods and limits to
control properties but avoid unacceptably high rates of non-
compliance
In order to ensure that industry concerns are properly addressed by the project, independent oversight is
provided by a stakeholder group comprising representatives from academia, the engineering profession,
the concrete industry and asset owners. The objective of the project is to achieve acceptance of FRGC
products by the industry and commercialise the technology to generate economic and environmental
benefits for the State of Victoria.
The focus of the project has been the production of precast tunnel segments because the use of fibre
reinforced concrete is already the preferred material for casting segments, because there are established
design methods (3), and because these are high-value products with a potential for good commercial
return. The project involves planning, laboratory and field trials, testing and marketing. A simplified flow
diagram is given in Figure 1, and the specification requirements are summarised in Table 2. The tests
include Australian Standard strength and durability tests, such as cylinder strength and apparent volume
of permeable voids, as well as European tests for water penetration and chloride migration.
3. Figure 1. Flow diagram showing the stages and output of the project.
FIELD TRIALS
LABORATORY
TRIALS
PROJECT PLAN
TESTING PLAN
SPECIFICATION
UPDATED TEST
DATA REPORTS
DESIGN GUIDES
TESTINGLONG-TERM
EXPOSURE
TESTS
PROTOTYPES
PROJECT
PLANNING
STAKEHOLDER
REVIEW
MARKETING TO
CONTRACTORS
MARKETING TO
ASSET OWNERS
STAKEHOLDER
REVIEW
TEST DATA
REPORTS
DESIGN GUIDES
STAKEHOLDER
REVIEW
4. Table 2. Summary of performance specification requirements.
Parameter Requirement Test Method
STRENGTH
28-day cylinder strength (MPa) 50 AS 1012.9
Cylinder strength for demoulding (MPa) 10 AS 1012.9
28-day tensile splitting strength (MPa) 4.2 AS 1012.10
28-day flexural strength (MPa) 4.6 ASTM C1609
28-day equivalent post-crack residual flexural strength
Fe3.0 (MPa)
3.2 ASTM C1609
DURABILITY
AVPV rodded (%) 13 AS 1012.8
28-day water penetration (mm)
Mean of 2 tests
20 BS EN 12390-8
56-day chloride migration coefficient (m2
/s)
91-day chloride migration coefficient (m2
/s)
4x10-12
2x10-12
NTB 443
Sorptivity (mm) 8 RTA T362
56-day drying shrinkage (microstrain) 600 AS 1012.13
3. Discussion
3.1 Laboratory Trials
3.1.1 Initial and Main Trials
The initial laboratory trials assessed the workability characteristics of FRGC mixes using different
fibre types, and doses of synthetic fibres from 8-12 kg/m
3
. A Portland cement based concrete
containing 8 kg/m
3
of synthetic fibres and geopolymer concrete with 40 kg/m
3
steel fibres provided
two control mixes. The Portland cement control mix was based on an existing production mix, with
20% fly ash in the binder and a water/binder ratio of less than 0.4.
The synthetic fibres are manufactured from polyolefin and are 60mm long and 0.5-1mm in diameter
with an embossed profile. The steel fibres are formed from cold drawn high tensile carbon steel
and are 60 mm long and 0.75 mm in diameter with hooked ends.
Based on the initial trials a geopolymer mix with 8 kg/m
3
of synthetic fibre with was selected for
further development in the main trials. This mix gave a 100mm target slump 60 minutes after
mixing (allowing for permissible tolerances).
The main laboratory mixes were 0.35m
3
in size and were produced at a batching plant at
Campbellfield in Victoria. A large number specimens were produced, including ASTM C1550 round
panels for toughness. The key findings from the laboratory trials are discussed below.
3.1.2 Strength
The strength results are summarised in Table 3.
Standard and accelerated curing were used to determine the effect on the early strength gain for
demoulding. For one production cycle every 24 hours the strength gain of the FRGC mix did not
require any accelerated curing, although at lower ambient temperatures (<15°C) heat curing may
be beneficial
5. Table 3. Summary of strength results for laboratory trials.
Parameter
Conventional
concrete with
synthetic fibres
Geopolymer
concrete with
steel fibres
Geopolymer
concrete with
synthetic fibres
28-day cylinder strength (MPa) 52.5 46.0 49.5
1-day cylinder strength for demoulding (MPa)* 25.0 24.0 25.0
28-day tensile splitting strength (MPa)* 4.8 4.0 3.4
28-day flexural strength (MPa)* 5.5 6.4 7.4
28-day equivalent post-crack residual flexural strength Fe3.0
(MPa)*
3.7 3.8 3.9
Note: * denotes accelerated-cured specimens
It can be observed that the compressive and tensile splitting strengths of the geopolymer concrete
were lower than those of the Portland cement based control and the typical specification
requirements. However, the flexural strength is of primary importance in the performance of tunnel
segments, and the flexural strength and equivalent post-crack residual flexural strength value at
3.0mm deflection of the geopolymer with synthetic fibres slightly exceed those of both the Portland
cement based control and the geopolymer mix with steel fibres. This is shown graphically in Figure
2.
0
1
2
3
4
5
6
7
8
Conventional concrete with
synthetic fibres
Geopolymer concrete with
steel fibres
Geopolymer concrete with
synthetic fibres
Strength(MPa)
Flexural strength Eq. (Post-crack) Residual Strength, Fe0.75
Eq. (Post-crack) Residual Strength, Fe3.0
Figure 2. Flexural strength results.
Conventional concrete mixes with steel fibres have shown a tendency to embrittlement as the
concrete strength increases due to fibre rupture rather than gradual pull-out (2). The good
equivalent post-crack residual flexural strength values of the geopolymer mix with synthetic fibres is
encouraging, and this value would not be expected to be reduced by long-term strength gain of the
concrete in the same way as steel fibres because of the lower elastic modulus of synthetic fibres.
3.1.3 Durability
The durability test results are summarised in Table 4.
The Apparent Volume of Permeable Voids of the geopolymer mixes were higher than that of the
Portland cement based control, and also exceeded the specified limit of 13%. In contrast, the
chloride migration, sorptivity and dying shrinkage of the geopolymer mixes are significantly better
than those of the Portland cement based control.
6. Table 4. Summary of durability test results for laboratory trials.
Parameter Conventional concrete with
synthetic fibres
Geopolymer concrete with
steel fibres
Geopolymer concrete with
synthetic fibres
AVPV rodded (%) 13 17 14
28-day water penetration (mm)
Mean of 2 tests
<20mm <20mm <20mm
56-day chloride migration
coefficient (m2
/s)
91-day chloride migration
coefficient (m2
/s)
3.45
1.87
Not tested
Not tested
1.08
0.91
Sorptivity (mm) 9.0 6.1 6.2
56-day drying shrinkage
(microstrain)
530 240 400
One potential reason for the above differences is the lack of a conventional capillary pore structure
in geopolymer concrete. This means that parameters which are heavily influenced by capillary
porosity and capillary transport of moisture could be beneficially influenced by using geopolymer
concrete.
3.2 Field Trials
Field trials of up to 2.5m
3
size were undertaken at the Hume precast plant in Echuca, Victoria. Tunnel
segment moulds were already available at this plant from a recently completed project. The objective of
the field trials was to produce prototype segments, as well as larger specimens for further testing (Section
3.4). A conventional concrete control mix with steel fibres was also included.
The field trials used a FRGC with 8 kg/m
3
of synthetic fibres and Portland cement based concrete with 40
kg/m
3
of steel fibres (with and without the addition of 1 kg/m
3
of synthetic microfibers for improved fire
spalling resistance).
Four rectangular bolted segments (each approximately 0.4m
3
and 0.8 tonnes in weight) and four smaller
tapered key segments (each approximately 0.1m
3
and 0.2 tonnes in weight) were produced from the
FRGC mix. The compressive strength development of the FRGC mix was similar to the control mix and
met the performance specification. The segments were successfully stripped to allow a single casting
cycle every 24 hours at an ambient temperature at casting of 22°C.
0
10
20
30
40
50
60
70
80
1 day 7 days 28 days
Compressivestrength(MPa)
Conventional concrete
with steel fibres
Geopolymer concrete
with synthetic fibres
Figure 3. Compressive strength development, field trials.
7. Figure 4 shows the typical condition of the demoulded segments and a sawn cross-section. The cross-
section shows good uniformity and compaction, although care has to be taken to evenly disperse the
fibres during mixing and to cure the concrete adequately.
Figure 4. Prototype tunnel segments and sawn cross-section
3.3 Embodied carbon
Reducing the carbon emissions of concrete is a key driver for the project. In order to assess the impact of
using FRGC compared to conventional concrete, two scenarios were considered:
a) Casting FRGC or conventional concrete segments at Echuca, Victoria for delivery by road
220km to a project site in Melbourne; and
b) Casting FRGC segments at Echuca, Victoria for delivery by road 3310km to a project site
in Perth, Western Australia.
The first case represents a realistic supply situation for precast segments, whereas the second case is
intended to represent a maximum transport distance in order to assess the influence of haulage on carbon
emissions.
The carbon emissions were calculated using published values for converting energy and fuel to CO2 (4).
The calculations assumed that the strength and durability performance of the FRGC and conventional
concrete mixes are similar. The FRGC concrete has 8 kg/m
3
of synthetic fibres and conventional concrete
assumes 40 kg/m
3
of steel reinforcing bar or steel fibres.
The calculations allow for the embodied carbon in the constituent materials (including obtaining and
processing the raw materials), transportation to the precast plant, production of the segments and their
transportation to the project site. The calculations do not assess the effects of carbonation, or the carbon
emission associated with demolition and reuse of tunnel segments.
Figure 5 shows the comparison between FRGC and conventional concrete. The CO2 emissions of
segments produced at Echuca using FRGC are 34% and 60% of the values for conventional concrete
segments delivered to sites in Melbourne and Perth, representing a reduction of up to approximately 70%
in emissions. The influence of binder and reinforcement upon carbon emissions predominates over
transportation. The CO2 emissions for FRGC segments transported to Perth are slightly less than those
associated with conventional concrete segments delivered to Melbourne, indicating that binder and
reinforcement type predominate over transportation.
8. 0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Melbourne Perth
Totalemission(tonneCO2/tonnesegment)
Conventional concrete
with steel rebar/fibres
Geopolymer concrete
with synthetic fibres
Figure 5. Carbon emissions associated with FRGC and conventional concrete segments produced
in Echuca and delivered to sites in Melbourne and Perth.
3.4 Further work
The following further work is planned:
• Exposure tests
• Creep tests
• Fire resistance tests
• Project trials.
FRGC samples are being exposed to abrasion and acid sulphate conditions to simulate a sewer
environment. These exposure conditions, using a sulphuric acid solution with a pH of 2, are intended to
last at least 2 years. The interim results at 140 days are shown below in Figure 6. These very early
results indicate a slightly lower depth of attack in FRGC concrete compared to the Portland cement based
control. The steel fibres produce a slightly lower depth of attack, which may reflect enhanced abrasion
resistance compared to synthetic fibres. These trends need to be verified in the long-term exposure data.
Creep tests will be undertaken using cracked ASTM C1550 round panels to establish the difference in
performance between a Portland cement based control with steel fibres and FRGC using synthetic fibres.
Previous results of such tests using Portland cement based concrete have shown comparable
performance of steel fibre and synthetic fibre reinforced concrete, dependent on the loading (2).
Fire testing to assess spalling resistance is a common requirement for the lining of transportation tunnels.
Tunnel segments from the field trials are being fire tested at Victoria University to simulate a hydrocarbon
fire.
Following successful completion of the laboratory and field trials, opportunities are being sought to use
FRGC in project trials. This is an important step to secure early application of the technology to benefit the
construction industry and wider society.
9. 0
0.5
1
1.5
2
2.5
3
0 50 100 150
Time of exposure (days)
Depthofdamage(mm)
Portland Cement Concrete
with Synthetic Fibres
Geopolymer Concrete with
Synthetic Fibres
Geopolymer Concrete with
Steel Fibres
Figure 6. Depth of damage under abrasion and acid sulphate conditions.
4. Conclusions
Use of concrete in construction contributes over 5% of worldwide carbon dioxide emissions. If emission
targets are to be met some radical changes need to be made to reduce this value. The use of geopolymer
binder and synthetic fibres in place of Portland cement and steel reinforcement to produce fibre reinforced
geopolymer concrete (FRGC) provides a lower carbon alternative to conventional concrete.
A 3-year study involving is being undertaken to develop and commercialise FRGC products for use in
underground infrastructure. The work involves laboratory studies, long-term exposure tests, production of
prototype tunnel segments and a life cycle assessment of embodied carbon for the products. The
properties of the fresh and hardened FRGC have been investigated, including workability, strength and
durability. The latter has included standard parameters, such as AVPV, as wells as chloride migration
testing and exposure to acid and sulphate solutions.
Mix designs utilising different fibre dosages and geopolymer binders have been assessed, together with
standard and accelerated curing regimes. The objective of the testing has been to provide information on
the essential engineering characteristics of the material using a typical specification as the basis for
compliance. Control mixes using Portland cement and 40 kg/m
3
of steel fibres were also tested for
comparison purposes.
The work indicates that combining geopolymer binder and 8 kg/m
3
of synthetic fibres produces concrete
with acceptable workability. The hardened properties are encouraging when assessed against a typical
specification for tunnel segments.
The test results show that FRGC can outperform the Portland cement based control in respect of flexural
strength, shrinkage and durability and at the same time can reduce carbon emissions by approximately
70%.
Field trials and production of prototype segments have been successfully completed. Further long-term
testing is continuing and opportunities are being sought for project trials.
5. Acknowledgement
The authors acknowledge the substantial contributions made by Dr Van Bui in management of the project
and analysis of the data. The financial support of the Victorian Government through the Victoria’s Science
Agenda program is also acknowledged.
10. 6. References
1. Wimpenny D E, “Low carbon concrete- options for the next generation of infrastructure”, 24
th
Biennial Conference of the Concrete Institute of Australia, Sydney, Australia, 2009.
2. Wimpenny D E, Angerer W, Cooper A, Bernard S, “The use of Steel and Synthetic Fibres in
Concrete under Extreme Conditions”, 24
th
Biennial Conference of the Concrete Institute of
Australia, Sydney, Australia, 2009.
3. King M R, and Alder A J, ”The practical specification of steel fibre reinforced concrete (SFRC) for
tunnel linings”, Proceedings of Underground Construction 2007 Conference, London, Brintex Ltd.
4. Halcrow, “Development of Fibre Reinforced Geopolymer: Concrete-Life Cycle Assessment
(LCA)”, January 2011.