Sustainability, Durability, and Fiber-Reinforced Concrete
Presented By: Beverly Heasley
Affiliation: FORTA
Description: In today's 'throw-away culture' it is more important than ever to understand how everyone can contribute to greener, more sustainable, carbon-neutral living.
The case studies covered in this presentation show how using fiber-reinforcement in concrete construction plays a key part of the construction industry's role in this effort - from large-scale infrastructure and industrial projects to small business and residential projects.
Behavior of Steel Fibers in Concrete with Alkali-Activated Binder Material
Presented By: Hendrik Thooft
Affiliation: Bekaert NV
Description: The conventional production of Portland cement significantly contributes to CO2 emissions. As the construction industry strives to reduce its carbon footprint, innovations like steelfiber reinforced concrete have already taken a step in the right direction. Another promising approach is alkali-activated cement (AAC), which aims to further reduce CO2 emissions. AAC combines materials such as slag, blast furnace, and activators. However, variations in “slag” sources can significantly impact material behavior and its interaction with steel. In this presentation, we will delve into the multiple variables affecting the durability and performance of steelier concrete with AAC.
Fiber Reinforced Concrete for the Design of Efficient and Sustainable Gravity Energy Storage Systems
Presented By: Francesco Lo Monte
Affiliation: Politecnico di Milano
Description: The construction industry is a key sector worldwide due to its monumental social and economic impact. Infrastructure plays a pivotal role, not only with an expected 1.5 Keynesian multiplier, but also because it is able to steer the transition towards a carbon neutral society, providing crucial sectors of future economy (including those following under the umbrella of Green and Blue Growths). Given that concrete is the most used construction material, its role in the aforesaid framework is of paramount importance. The demand for more efficient concretes and concrete structures necessarily promotes an increase in the sustainability signature in the Construction Sector, which strategically accompanies this social and economic transition. In this context, (High-Performance) Fibre-Reinforced Concrete – (HP)FRC is a promising alternative to conventional reinforced concrete, allowing for more efficient production processes (including a more efficient structural use of the material, the reduction in the use of traditional reinforcement and a more efficient implementation of digital fabrication) and/or for the increase of the service life of structures thanks to its inherent improved durability. In the present paper, the adoption of (HP)FRC for an innovative Gravity Energy Storage System is described, starting from the mechanical characterization of material properties, following with the calibration of numerical modelling and then the structural design.
Precast Concrete Slabs Reinforced with Recycled Steel Fibers to Satisfy Green Public Procurement
Presented By: Alessandro Fantilli
Affiliation: Polytechnic University of Turin
Description: To build environmentally friendly public constructions, authorities impose to tailor concrete mixtures with a minimum content of recycled materials. To satisfy this green public procurement (GPP) in frame structures, whose mass is mainly distributed on horizontal diaphragms, it is necessary to draw the attention to the slabs of floors. As ready-mixed concrete with recycled materials is not easily available on the market, partially prefabricated one-way slabs, composed by both cast-in-situ concrete and precast plates (generally called predalles) were investigated. Only the precast concrete of predalles contained recycled materials, such as supplementary cementitious materials (SCM) in place of CEM I, recycled concrete aggregate (RCA) and rubber to replace stone aggregate, and recycled steel fibers (RSF). These were used to cast full-scale one-way slabs, subsequentially tested in three-point bending. Test results and numerical analyses revealed an equivalence between the traditional rebar and RSF. The latter effectively compensated the loss of flexural strength that the substitution of virgin materials produced. Thus, if large quantities of SCM, RCA, rubber, and RSF are in the concrete of predalles, slab can satisfy both GPP and the mechanical performances, though the cast-in-situ concrete does not contain any recycled material.
Reducing Carbon Footprint by 50 % by Using Steel Fiber Reinforced Self-Stressing Concrete (SFRSSC) Ground and Suspended Slabs
Presented By: Rolands Cepuritis
Affiliation:
Description: In Europe steel-fiber reinforced self-stressing concrete (SFRSSC) has been developed and successfully applied for achieving embodied carbon savings in ground and suspended slabs for close to 20 years. In this slab-system, by chemically pre-stressing the concrete matrix, the generated compressive self-stress can be used to significantly decrease the thickness of the structures while maintaining their load bearing capacity. By decrease in the total volume of material used, optimisation of the concrete matrix mix-composition and overall improvement in the production process, up to 50 % reduction in the reduced embodied carbon emissions become achievable. In addition, these slabs offer a series of improved serviceability aspects, such a better durability, increased construction joint stability, improved stiffness, better crack control and others.
Rapid Strength Gaining FRC for Sustainable Regeneration of Tunnel Linings
Presented By: Liberato Ferrara
Affiliation: Polytechnic University of Milan
Description: Infrastructures have a strategic role for the society’s development, by making possible the motion of thousands of people that everyday needs to reach a specific location. Considering all the structural typologies involved in the infrastructure network, tunnels can be considered among the most critical. Dealing with the Italian infrastructure network, most of the tunnels need maintenance interventions to restore the service life, as they have been built around fifty years ago. To this purpose, in an era of rapid urbanization and growing environmental concerns, an important advancement must be done in the tunnel retrofitting technology, by speeding up the overall process reducing costs and time related, as well as increasing the sustainability of the interventions, by reducing the CO2 emissions and by improving the waste management. The start-up company Hinfra is introducing a new methodology for the regeneration of existing tunnels by means of an automated process based on slip-forming of Steel Fiber Reinforced Concrete (SFRC). The present work wants to focus on the comparison between this new retrofitting methodology and the traditional approach, with the use of ordinary steel rebars in the latter, highlighting the differences in the design, material properties and construction phases. The comparison made between the two approaches is referred to a specific case of study, the Ragnaia II tunnel in the A1 highway in the Italian roadway network, and it is performed through a cradle-to-gate Life Cycle Analysis (LCA), with particular concern on the Global Warming Potential (GWP) index. A durability analysis is also performed, focusing on carbonation and chloride penetration, to extend the system boundaries beyond the gate. Additional analyses explore the influence of traffic both environmentally and socioeconomically, emphasizing dependence on the construction duration and stressing the importance of extending the system boundaries beyond the gate.