250
L. Biolzi et al.
Keywords High-performance concrete · Calcium sulfoaluminate cement (CSA) ·
Granulated blast-furnace slag (GGBS) · Double hooked-end steel fibers ·
Mechanical properties · SEM observation
1 Introduction
Portland cement concrete is the most widely used human-made material on the
planet; around 25 billion metric tons are produced globally each year (Celik et al.
2014). Recently, the demand for using high-performance concrete (HPC) has widely
increased throughout the world. As is commonly known, for the production of an HPC
matrix, a large amount of binder is normally used. Even though the reasons for concrete’s dominance are diverse, the massive production and consumption cycle of concrete have a significant environmental impact, making the concrete industry unsustainable. Currently, Portland cement concrete production accounts for around 7% of
carbon dioxide (CO 2 ) emissions annually. Most of the emissions are attributable to the
production of ordinary Portland cement (OPC) clinker. The current approach to overcome this problem is through the reducing clinker factor and through replacing OPC
with supplementary cementitious materials such as fly ash, slag, silica fume, and natural pozzolan (Gartner & Hirao 2015). However, due to growing field experience and
increasing demand for those materials, there is an essential need to develop concrete
made with a new kind of cement such as calcium aluminate cements (CAC), calcium
sulfoaluminate cement (CSA), alkali-activated binders, and supersulfated cements
(Juenger et al. 2011). Recently, CSA cement gained an increased attention due to
its lower amount of CO 2 emission as compared to that of OPC (Gartner 2004). It is
reported that the CO 2 emissions may drop by up to 35% if OPC is replaced with CSA
cement (Berger et al. 2013). Additionally, concretes fabricated with CSA cement can
result in an increased sulfate resistance, high impermeability and chemical resistance
and a low chance for alkali–silica reactions (Tang et al. 2015).
Several benefits of HPC compared to conventional concretes have significantly
increased its use in different structural applications. However, the brittleness of HPC
is higher with respect to the normal-strength concrete due to the higher strength,
which subsequently increases the vulnerability of HPC to the initiation and propagation of cracks of different sizes within the concrete body (Savino et al. 2018). The
addition of discrete fibers in concrete is recognized as a suitable solution to overcome
this weakness and develop materials with enhanced tensile strength, flexural strength,
toughness, and thermal shock strength (Sanal et al. 2016; Afroughsabet et al. 2016,
2018; Cattaneo and Biolzi 2010; Simões et al. 2017). This study was aimed at analyzing the effects of CSA cement and DHE steel fibers on the engineering properties
of HPC. Compressive strength, splitting tensile strength, flexural strength, modulus
of elasticity, and microstructural observations were performed in order to evaluate
the properties of concrete at different curing ages. The findings of this research are
highly promising and show that the simultaneous use of CSA cement and DHE steel
fibers can significantly increase the engineering properties of HPC.
L. Biolzi et al.
Keywords High-performance concrete · Calcium sulfoaluminate cement (CSA) ·
Granulated blast-furnace slag (GGBS) · Double hooked-end steel fibers ·
Mechanical properties · SEM observation
1 Introduction
Portland cement concrete is the most widely used human-made material on the
planet; around 25 billion metric tons are produced globally each year (Celik et al.
2014). Recently, the demand for using high-performance concrete (HPC) has widely
increased throughout the world. As is commonly known, for the production of an HPC
matrix, a large amount of binder is normally used. Even though the reasons for concrete’s dominance are diverse, the massive production and consumption cycle of concrete have a significant environmental impact, making the concrete industry unsustainable. Currently, Portland cement concrete production accounts for around 7% of
carbon dioxide (CO 2 ) emissions annually. Most of the emissions are attributable to the
production of ordinary Portland cement (OPC) clinker. The current approach to overcome this problem is through the reducing clinker factor and through replacing OPC
with supplementary cementitious materials such as fly ash, slag, silica fume, and natural pozzolan (Gartner & Hirao 2015). However, due to growing field experience and
increasing demand for those materials, there is an essential need to develop concrete
made with a new kind of cement such as calcium aluminate cements (CAC), calcium
sulfoaluminate cement (CSA), alkali-activated binders, and supersulfated cements
(Juenger et al. 2011). Recently, CSA cement gained an increased attention due to
its lower amount of CO 2 emission as compared to that of OPC (Gartner 2004). It is
reported that the CO 2 emissions may drop by up to 35% if OPC is replaced with CSA
cement (Berger et al. 2013). Additionally, concretes fabricated with CSA cement can
result in an increased sulfate resistance, high impermeability and chemical resistance
and a low chance for alkali–silica reactions (Tang et al. 2015).
Several benefits of HPC compared to conventional concretes have significantly
increased its use in different structural applications. However, the brittleness of HPC
is higher with respect to the normal-strength concrete due to the higher strength,
which subsequently increases the vulnerability of HPC to the initiation and propagation of cracks of different sizes within the concrete body (Savino et al. 2018). The
addition of discrete fibers in concrete is recognized as a suitable solution to overcome
this weakness and develop materials with enhanced tensile strength, flexural strength,
toughness, and thermal shock strength (Sanal et al. 2016; Afroughsabet et al. 2016,
2018; Cattaneo and Biolzi 2010; Simões et al. 2017). This study was aimed at analyzing the effects of CSA cement and DHE steel fibers on the engineering properties
of HPC. Compressive strength, splitting tensile strength, flexural strength, modulus
of elasticity, and microstructural observations were performed in order to evaluate
the properties of concrete at different curing ages. The findings of this research are
highly promising and show that the simultaneous use of CSA cement and DHE steel
fibers can significantly increase the engineering properties of HPC.