Project

Back to overview

Low-clinker, high-performance concrete elements pre-stressed with carbon-fiber reinforced polymer reinforcement (LCHPC)

English title Low-clinker, high-performance concrete elements pre-stressed with carbon-fiber reinforced polymer reinforcement (LCHPC)
Applicant Lura Pietro
Number 154057
Funding scheme NRP 70 Energy Turnaround
Research institution Abteilung Analytische Chemie EMPA
Institution of higher education Swiss Federal Laboratories for Materials Science and Technology - EMPA
Main discipline Civil Engineering
Start/End 01.01.2015 - 31.12.2018
Approved amount 211'994.00
Show all

All Disciplines (2)

Discipline
Civil Engineering
Material Sciences

Keywords (9)

structure; CO2; Supplementary cementitious materials; shrinkage; prestress losses; creep; fire resistance; Carbon fibre; bond

Lay Summary (Italian)

Lead
L'obbiettivo di questo progetto e' sviluppare delle innovative miscele di calcestruzzo ad alte prestazioni e a ridotto contenuto di cemento(almeno il 50% in meno), da usare per realizzare elementi precompressi sottili in calcestruzzo rinforzato con cavi di precompressione in materiale polimerico con fibra di carbonio. Questa tecnologia permettera' di realizzare elementi strutturali (travi, elementi di facciata, etc.) molto leggeri, ma ad alta resistenza e durabilità e al contempo a ridotto impatto ambientale grazie al basso contenuto di cemento.
Lay summary

In sintesi

Malgrado il basso impatto ambientale in confronto ad altri materiali da costruzione, soprattutto per via delle ingenti quantita‘ prodotte, il calcestruzzo finisce per consumare circa il 3% dell’energia primaria e risulta responsabile di circa il 5% delle emissioni di anidride carbonica. L’impatto ambientale proviene soprattutto dalla produzione del cemento e delle armature d’acciaio.

Una soluzione particolarmente efficace, sviluppata negli ultimi anni, consiste nel realizzare elementi precompressi sottili in calcestruzzo ad alte prestazioni e autocompattante, rinforzato con cavi di precompressione in materiale polimerico con fibra di carbonio. Questa tecnologia permette di realizzare elementi strutturali (travi, elementi di facciata, etc.) molto leggeri, ma ad alta resistenza e durabilità.

 

Soggetto e obiettivo

Il calcestruzzo utilizzato in queste applicazioni contiene una quantità elevata di cemento, che comporta un alto livello di energia grigia e nel contempo scorrimento viscoso e ritiro elevati, i quali inducono notevoli perdite di precompressione. Per superare questi problemi, in questo progetto il contenuto di cemento nel calcestruzzo verra‘ ridotto del 50-80%, sostituendolo con diversi tipi di aggiunte minerali (polvere di calcare, ceneri volanti, fumo di silice, etc.) ed al contempo riducendo drasticamente il rapporto acqua/cemento. La riduzione del rapporto acqua/cemento e‘ necessaria per garantire bassa porosita‘, alta resistenza a compressione e buona adesione con i cavi di precompressione, ma potrebbe risultare in un aumento del ritiro che dovra‘ essere compensato con soluzioni ah hoc.

 

Contesto socio-scientifico

Il nostro lavoro permetterà di ottenere ricette per calcestruzzo ad alte prestazioni a basso contenuto di cemento, con basso impatto ambientale e allo stesso tempo piu‘ economiche. Queste ricette potranno essere direttamente trasferite al settore industriale grazie a collaborazioni in corso con un prefabbricatore e con un produttore di calcestruzzo.

Direct link to Lay Summary Last update: 22.10.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
Low clinker high performance concretes and their potential in CFRP-prestressed structural elements
Lämmlein Tobias Dominik, Messina Francesco, Wyrzykowski Mateusz, Terrasi Giovanni Pietro, Lura Pietro (2019), Low clinker high performance concretes and their potential in CFRP-prestressed structural elements, in Cement and Concrete Composites.
Bond Performance of Sand Coated UHM CFRP Tendons in High Performance Concrete
Lämmlein Tobias, Messina Francesco, Griffa Michele, Terrasi Giovanni, Lura Pietro (2017), Bond Performance of Sand Coated UHM CFRP Tendons in High Performance Concrete, in Polymers, 9(12), 78-78.
Transient Thermal Tensile Behaviour of Novel Pitch-Based Ultra-High Modulus CFRP Tendons
Terrasi Giovanni, McIntyre Emma, Bisby Luke, Lämmlein Tobias, Lura Pietro (2016), Transient Thermal Tensile Behaviour of Novel Pitch-Based Ultra-High Modulus CFRP Tendons, in Polymers, 8(12), 446-446.

Collaboration

Group / person Country
Types of collaboration
Holcim Group Support Switzerland (Europe)
- Industry/business/other use-inspired collaboration
Carbo-link AG Switzerland (Europe)
- Industry/business/other use-inspired collaboration
SACAC AG Switzerland (Europe)
- Industry/business/other use-inspired collaboration

Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
NRP 70 Concrete Solutions First Stakeholders Meeting Workshop 17.06.2015 Bern, Switzerland Lura Pietro; Lämmlein Tobias Dominik;


Associated projects

Number Title Start Funding scheme
154057 Low-clinker, high-performance concrete elements pre-stressed with carbon-fiber reinforced polymer reinforcement (LCHPC) 01.01.2015 NRP 70 Energy Turnaround

Abstract

Sustainability considerations in precast concrete have led to the development of novel thin-walled concrete structural elements. Empa’s effort in the last decade has focussed on the development of self-consolidating, high-performance concrete (HPC) reinforced with prestressed tendons made of high-strength, lightweight, and non-corroding carbon fibre reinforced polymer (CFRP). With this technology, filigree, lightweight, high strength and high durability concrete structural elements become possible.As common for HPC, the concrete used in these applications contained a high amount of Portland cement. This is a limitation of the system in terms of energy consumption and CO2 footprint and causes high creep and shrinkage losses of prestress. To overcome these problems, in this project we propose to reduce the clinker content in the HPC by 50-80%, while at the same time guaranteeing high strength, good bond with the CFRP tendons and limited shrinkage and creep. To reach these goals, new HPC mixtures with very low water content (to reduce porosity) and high content of filler and supplementary cementitious materials will be developed (Task 1). The shrinkage of the HPC will be reduced by internal curing to limit prestress losses (Task 2). To assess the structural performance of the new HPC in the thin prestressed elements, experiments on pull-out and bending (Task 3) and FEM simulations will be performed (Task 4).The immediate outcome of the project will be cheaper, low-clinker HPC recipes that can be directly transferred to industry thanks to an ongoing collaboration with a concrete precaster. The scientific output of the project will be the characterization of hydration and volume changes in HPC with very low clinker content and a better understanding of bond mechanisms and prestress losses in prestressed HPC, either with CFRP tendons or traditional steel tendons. This project contributes directly to the fundamental goals of the joint project “Concrete solutions”, namely reducing the clinker content in concrete and reducing the use of steel in concrete and thereby it contributes to reducing the grey energy of building materials.
-