Durability of an UHPC containing spent equilibrium catalyst

Matos, Ana Mafalda; Nunes, Sandra; Costa, Cristiana; Aguiar, J. L. Barroso de

doi:10.1016/j.conbuildmat.2021.124681

Cited by 11 publications

(6 citation statements)

References 72 publications

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“…Th a smaller peak occurred at 70 nm, and no pores larger than 100 nm were found. The a age pore diameter corresponds to 8.8 nm, and the total porosity is 4.8%, which seem agree with previous studies [29]. In Figure 3b, the measured pore distribution is divi into three size ranges: gel or micropores (<10 nm), capillary pores (10-5000 nm), macro pores (>5000 nm), according to [59].…”

Section: Porosity and Microstructuresupporting

confidence: 90%

“…Nevertheless, the pores' size and interconnectivity are dependent on age, heat treatment, the w/b ratio, the type of cement, and the use of supplementary cementitious materials (SCM) or nanomaterials [26][27][28]. The literature survey shows that the average UHPFRC porosity corresponds to 6.4% for a w/b ratio range of 0.13-0.22 and a compressive strength of 100-279 MPa [29]. This compact microstructure is responsible for both mechanical and durability behaviour.…”

Section: Introductionmentioning

confidence: 99%

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Susceptibility to Expansive Reactions of a Greener UHPC: Micro to Macro-Scale Study

Matos

2022

Applied Sciences

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Nowadays, in Europe, several infrastructures, such as bridges, viaducts, and maritime structures, are in an advanced state of degradation. Therefore, novel repair/rehabilitation techniques are sought. Recent advances in ultra-high-performance fibre-reinforced cement-based composites (UHPFRC) represent a significant step towards resilient structures. In addition to their remarkable mechanical properties (compressive strength > 150 MPa), they present extremely low permeability and, as a premise, very high durability. Despite their relatively high cost, UHPFRC can be a competitive solution for rehabilitation/strengthening applications where smaller volumes are needed. UHPFRC applied in thin layers (with or without reinforcement) can replace carbonated and/or cracked concrete acting as a protective watertight and/or strengthening layer. The structural capacity increases (stiffness, ultimate strength), and the durability is expected to improve significantly while keeping cross-sectional dimensions. Additional advantages are expected, such as reduced intervention time, fewer maintenance routines, reduced life-cycle cost, and longer service life. Although much of the focus on UHPFRC has centred on mechanical and/or structural performance, durability is inevitably linked with mechanical properties. The current work evaluated the durability of non-property and greener UHPC concerning expansive reactions, alkali-silica reactions and expansion due to external sulphates, by macro and micro-scale integrative study. Linear expansion tests were performed in UHPC specimens according to ASTM C 1260 and LNEC E−364. At the macro level, no deleterious expansion due to ASR or external sulphate occured. Expansion due to ASR was 0.0018% after 14 days of immersion in an alkali-rich environment, and no expansion was recorded regarding sulphate attack. However, SEM analysis reveals reactive products of ASR and sulphate attack, namely, ASR gel and ettringite, respectively, in UHPC specimens.

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Section: Porosity and Microstructuresupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Susceptibility to Expansive Reactions of a Greener UHPC: Micro to Macro-Scale Study

Matos

2022

Applied Sciences

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Section: Research Objectivesmentioning

confidence: 99%

“…An evaluation of several durability indicators of new developed UHPC (without steel fibres) to determine the resistance against various aggressive agents was conducted in a previous study [42,43,58], and results of durability indicators show that new UHPC presents very high durability compared to OC and even HPC. Besides, it corroborates the range of durability parameters found in the literature for other UHPFRC [42,43,58]. The experimental characterisation of the capillary transport properties on cracked and non-cracked UHPFRC, with different fibre dosages, was also presented in previous work [44], and it showed its excellent tightness to water.…”

Section: Research Objectivesmentioning

confidence: 99%

Durability of an UHPFRC under mechanical and chloride loads

Matos

Figueiredo

Nunes

et al. 2021

Construction and Building Materials

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“…The ECAT was tested as being characterized by pozzolanic activity. The formation of calcium silicate hydrate (CSH) gel makes ECAT more beneficial for the production of concrete mixes, which is due to the fact that it reacts with the Ca(OH) 2 produced during the hydration of cement [11]. The benefits of using ECAT in the production of cementitious products such as paste [12], mortar [13], concrete [14], and UHPFRC [15] are presented in the literature.…”

Section: Introductionmentioning

confidence: 99%

Green Manufacturing of UHPFRC Made with Waste Derived from Scrap Tires and Oil Refineries

Abdolpour,

Muthu,

Niewiadomski

et al. 2024

Applied Sciences

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Ultrahigh-performance fiber-reinforced cement-based composite (UHPFRC) made with waste derived from scrap tires and oil refineries was tested in this study. The UHPFRC sample exhibited a maximum compressive strength of about 189 MPa at the end of 28 days. Steel fibers were recovered from scrap tires and were added up to 3% by volume in the UHPFRC samples. Such additions reduced cement flow by 11% but improved compressive strength by 21%. The equilibrium catalyst particles (ECAT) disposed of by oil refineries were used in amounts of up to 15% by weight as a replacement for cement in such UHPFRC samples. These aluminosilicate materials are spherical in shape and have a porous microstructure, which was found to reduce the cement flow by absorbing more free water onto their surfaces. They also reduced the heat and strength developments at early stages. However, the total cost of the final cement-based mixture and associated CO2 emissions were reduced by up to 7% and 15% due to the inclusion of the ECAT particles. These findings help to optimize the ECAT and recovered steel fibers in the UHPFRC mix design, and such waste valorization strategies can help achieve the goal of becoming carbon neutral.

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Durability of an UHPC containing spent equilibrium catalyst

Cited by 11 publications

References 72 publications

Susceptibility to Expansive Reactions of a Greener UHPC: Micro to Macro-Scale Study

Susceptibility to Expansive Reactions of a Greener UHPC: Micro to Macro-Scale Study

Durability of an UHPFRC under mechanical and chloride loads

Green Manufacturing of UHPFRC Made with Waste Derived from Scrap Tires and Oil Refineries

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