Papers

@article{rodriguez-alvaro_rheology_2025,

title = {Rheology and setting of self-compacting concrete incorporating high volume of fly ash and internal curing via coal and wood bottom ash},

author = {Roberto Rodríguez-Álvaro and Sindy Seara-Paz and Fernando Martínez-Abella and Belén González-Fonteboa},

url = {https://www.sciencedirect.com/science/article/pii/S2352710225016638},

doi = {10.1016/j.jobe.2025.113426},

issn = {2352-7102},

year  = {2025},

date = {2025-10-01},

urldate = {2025-10-01},

journal = {Journal of Building Engineering},

volume = {111},

pages = {113426},

abstract = {The continuous development of innovative high performance concretes is encouraging the use of new and sophisticated techniques to study their performance. In this article, a rheometer is used to determine the rheological parameters (dynamic yield stress, viscosity, yield stress at rest and thixotropy) of an internally cured self-compacting concrete with fly ash blended cement. This research is motivated by the scarcity of rheological studies regarding internally cured concretes. Coal bottom ash (CBA) and wood bottom ash (WA) were used as internal curing water reservoirs. Air content, setting times and temperature rise under semi-adiabatic conditions were also analysed. The results indicate that ball bearing effect of fly ash decreased the amount of high range water reducer admixture added to the mortars to get similar workability. Furthermore, all the rheological parameters increased when using coal bottom ash and, more remarkably, wood ash, due to their irregular shape, rough texture and some minor water absorption. Internal curing of fly ash blended cement concrete has no detrimental effects on the fresh state properties, but special attention must be paid to the pre-wetting of porous aggregates. If the internal curing water reservoirs are wetted below their water absorption capacities, their use reduces workability and setting times. Therefore, the practicality of the proposed mixtures relay mainly on the care taken during their design and materials conditioning. The future research efforts should focus on the development of new mixes with different supplementary cementitious materials and new conditioning techniques that guarantee a precise pre-wetting.},

keywords = {Internal curing, Shear thickening, Thixotropy, Viscosity, Yield stress},

pubstate = {published},

tppubtype = {article}

}

@article{cantero_self-healing_2025,

title = {Self-healing mechanisms in concrete cured in CO2-saturated environments: Synergistic effects of biomass forest ash and metakaolin},

author = {Blas Cantero-Chaparro and Sindy Seara-Paz and Estefania Cuenca and Liberato Ferrara and Belén González-Fonteboa},

url = {https://www.sciencedirect.com/science/article/pii/S0958946525002422},

doi = {10.1016/j.cemconcomp.2025.106160},

issn = {0958-9465},

year  = {2025},

date = {2025-10-01},

urldate = {2025-10-01},

journal = {Cement and Concrete Composites},

volume = {163},

pages = {106160},

abstract = {This study investigates the effect of autogenous self-healing in high-performance ternary concrete mixes incorporating biomass forest ash when exposed to concentration of carbon dioxide (CO2). To analyse this phenomenon, three cementitious systems were studied: i) 100 % Portland cement, ii) 60 % Portland cement, 25 % biomass ash, and 15 % metakaolin, and iii) 60 % Portland cement, 25 % limestone filler, and 15 % metakaolin. The samples, prepared with different initial crack widths, were subjected to four self-healing conditions: i) continuous immersion in tap water (TW), ii) wet-dry cycles in TW, iii) continuous immersion in carbonated water (CW), and iv) wet-dry cycles in CW, over two exposure periods (28 and 90 days). The effectiveness of the process was evaluated through the analysis of surface crack sealing using a digital microscope and the recovery of impermeability through water permeability tests. To understand the chemical mechanisms involved, the self-healing products formed were analysed using SEM. The results showed that the samples self-healed in CW tended to exhibit lower surface sealing efficiency compared to TW, regardless of the mix type, due to the slightly acidic pH caused by the dissolution of CO2 into carbonic acid. However, in the higher pH inside the cracks promoted the precipitation of calcium carbonates, improving internal impermeability even without achieving effective surface sealing. In this context, biomass ash was particularly effective as a water reservoir, promoting more efficient internal curing when combined with metakaolin and achieving better results in terms of internal impermeability than conventional mixes with cement or limestone filler combined with metakaolin.},

keywords = {Biomass ash, CO-Rich environments, Internal curing, Metakaolin, Self-healing concrete},

pubstate = {published},

tppubtype = {article}

}

@article{nduka_mechanical_2022,

title = {Mechanical and microstructural properties of high-performance concrete made with rice husk ash internally cured with superabsorbent polymers},

author = {David O. Nduka and Babatunde J. Olawuyi and Emmanuel O. Fagbenle and Belén González-Fonteboa},

url = {https://www.sciencedirect.com/science/article/pii/S240584402201790X},

doi = {10.1016/j.heliyon.2022.e10502},

issn = {2405-8440},

year  = {2022},

date = {2022-09-01},

urldate = {2026-08-10},

journal = {Heliyon},

volume = {8},

number = {9},

pages = {e10502},

abstract = {An experimental study was carried out to determine the properties of rice husk ash (RHA) and its effect on high-performance concrete's (HPC) mechanical and microstructural properties. RHA content was placed at 0–30% at 5% step intervals and a constant water-binder ratio (W/B) of 0.3. A slump flow test was carried out to measure the workability property of the fresh HPC. In contrast, the influence of RHA contents on compressive, splitting tensile, flexural strengths and microstructural properties were examined for the hardened HPC specimens. The X-ray fluorescence (XRF), scanning electron microscopy-energy dispersive x-ray (SEM-EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy-Attenuate total reflectance (FTIR-ATR), Thermogravimetry analysis (TGA), Brunauer, Emmett and Teller (BET) specific surface area and laser diffraction particle size distribution (PSD) were used to access the feasibility of RHA in HPC. XRD and SEM/EDX techniques were conducted to investigate the hydration products and microstructure in hardened HPCs. The post-test examination showed increased compressive, splitting tensile and flexural strengths of HPC samples for a 10% RHA content mix, recording the highest compressive strength in all curing ages. As the curing ages increase, the microstructure of the samples with RHA becomes denser than the control due to the refinement of the microstructure by the RHA incorporated. The XRD and SEM/EDX confirmed the lower calcium hydroxides from pozzolanic reactivity and later formation of C–S–H. The results suggest that RHA can be used as a cement replacement for up to 10% in HPC to produce sustainable concrete.},

keywords = {high-performance concrete, Internal curing, Microstructure and mechanical properties, Rice husk ash, superabsorbent polymers},

pubstate = {published},

tppubtype = {article}

}

@article{rodriguez-alvaro_waste-based_2021,

title = {Waste-Based porous materials as water reservoirs for the internal curing of Concrete. A review},

author = {Roberto Rodríguez-Álvaro and Sindy Seara-Paz and Belén González-Fonteboa and Verónica Ferrándiz-Mas and Kevin Paine},

url = {https://www.sciencedirect.com/science/article/pii/S0950061821020043},

doi = {10.1016/j.conbuildmat.2021.124244},

issn = {0950-0618},

year  = {2021},

date = {2021-09-01},

urldate = {2026-08-06},

journal = {Construction and Building Materials},

volume = {299},

pages = {124244},

abstract = {This review collates findings from more than 100 scientific publications regarding the performance of several waste-based porous materials (WASPORs) as water reservoirs for the internal curing of concrete. Results obtained by using recycled concrete aggregates, crushed ceramics, coal bottom ash, artificial waste-based aggregates, different powder materials and porous fibres were included. The influence of these WASPORs on the consistence, hydration, setting, microstructure, density, strength, modulus of elasticity, autogenous deformation, drying shrinkage and durability properties of concrete were analysed. General recommendations for suitable characterization of WASPOR and mix design are also given. The differences in water absorption capacity between the different porous materials studied have been used for explaining several of the observed phenomena. A moderate water absorption capacity together with a quick water desorption capacity were found to be among the key factors that define the internal curing efficiency of the proposed WASPORs.},

keywords = {High performance concrete, HPC, Internal curing, Porous aggregates, SCM, Supplementary cementitious material, Waste materials},

pubstate = {published},

tppubtype = {article}

}

@article{rodriguez-alvaro_internally_2020,

title = {Internally cured high performance concrete with magnesium based expansive agent using coal bottom ash particles as water reservoirs},

author = {Roberto Rodríguez-Álvaro and Belén González-Fonteboa and Sindy Seara-Paz and Khandaker M. A. Hossain},

url = {https://www.sciencedirect.com/science/article/pii/S095006182030982X},

doi = {10.1016/j.conbuildmat.2020.118977},

issn = {0950-0618},

year  = {2020},

date = {2020-08-01},

urldate = {2026-08-06},

journal = {Construction and Building Materials},

volume = {251},

pages = {118977},

abstract = {Shrinkage is one of the main concerns related to high performance concrete (HPC) durability. Its high density paste, consequence of a low water to binder ratio, can be unprofitable if cracks appear due to excessive tension when volume changes are restrained. Therefore, volume stability is a priority. In this work, three different strategies have been studied with that purpose: integration of fly ash as a low reactive supplementary cementitious material, internal curing via coal bottom ash particles as water reservoirs and the use of an expansive agent based on magnesium oxide (MEA). Many research works address the three shrinkage reduction strategies individually. However, studies regarding their simultaneous use are not prevalent so this work proposes its combined application. Results indicate that internal curing and MEA have a synergistic effect in HPC. Internal curing enhances MEA expansion due to the lack of water in this kind of concrete, contributing to autogenous shrinkage compensation. When concrete is affected by air-drying conditions, the use of MEA, internal curing, or both together make shrinkage to increase. MEA effectively expands in wet cured HPC although internal curing is not effective in this condition due to the absence of self-desiccation and limited porous aggregate water desorption. Taking into account the effects of each shrinkage reduction strategy and curing condition, it has been concluded that the use of fly ash as supplementary cementitious material, internal curing and MEA is recommended together with prevention of water evaporation from HPC surface.},

keywords = {Autogenous shrinkage, Coal bottom ash, Drying shrinkage, Fly ash, Internal curing, Magnesium based expansive agent, Swelling},

pubstate = {published},

tppubtype = {article}

}