Publicacións

@article{nduka_assessment_2023,

title = {Assessment of Water Transport and Chemical Attack of Meta-Illite Calcined Clay Blended Cement in High-Performance Concrete},

author = {David O. Nduka and Babatunde J. Olawuyi and Blas Cantero-Chaparro and Belén González-Fonteboa},

url = {https://www.mdpi.com/1996-1944/16/22/7149},

doi = {10.3390/ma16227149},

issn = {1996-1944},

year  = {2023},

date = {2023-01-01},

urldate = {2026-08-13},

journal = {Materials},

volume = {16},

number = {22},

pages = {7149},

publisher = {Multidisciplinary Digital Publishing Institute},

abstract = {Rapid urbanisation causes a rise in the need for infrastructure, which in turn fuels the creation of additional concrete and further increases cement supplies. Activation of illite-based clay mineral and usage in concrete production is one of the sustainable ways to address the cement industry anthropogenic issues. This study evaluates the durability properties of water transport (water absorption, and capillary water absorption), and resistance to aggressive environments (5% solutions of hydrochloric acid, HCl; sodium sulphate, Na2SO4; and calcium chloride, CaCl2) of meta-illite calcined clay (MCC)-based high-performance concrete (HPC). For this purpose, concrete was produced with 5, 10, 15, 20, 25 and 30% MCC content in partial substitution of CEM II. Results from the water absorption tests indicate an average percentage value of 3.57%, 3.35% and 2.52% for all the observed mixes at 28, 56 and 90 days, respectively, with MCCC-10 HPC having an average best value of 2.23% across the curing ages. On all observed days, the 5 to 15% cement replacements had very close average water sorptivity value of 0.125 ± 0.001 mm/min0.5 with the control mix (0.113 ± 0.011 mm/min0.5). The aggressive environments exposure findings of the hardened MCC-based HPC specimens of 10 to 20% recorded an approximately 15% compressive strength loss in HCl, Na2SO4 and CaCl2 solutions over the 90 days of curing. In all, the HPC mixes of 5 to 15% MCC content obtained an average durability performance factor of 89%. As a result, these findings imply that MCC can replace cement in up to 15% of HPC production.},

keywords = {durability properties, high-performance concrete, meta-illite calcined clay, superabsorbent polymers},

pubstate = {published},

tppubtype = {article}

}

@article{nduka_effect_2021,

title = {Effect of KyAl4(Si8-y) O20(OH)4 Calcined Based-Clay on the Microstructure and Mechanical Performances of High-Performance Concrete},

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

url = {https://www.mdpi.com/2073-4352/11/10/1152},

doi = {10.3390/cryst11101152},

issn = {2073-4352},

year  = {2021},

date = {2021-10-01},

urldate = {2026-08-06},

journal = {Crystals},

volume = {11},

number = {10},

pages = {1152},

publisher = {Multidisciplinary Digital Publishing Institute},

abstract = {The work described in this paper has been performed to determine the potential use of meta-illite (KyAl4(Si8-y) O20(OH)4) calcined clay (MCC) as a supplementary cementitious material (SCM) in a binary Portland cement (PC) for high-performance concrete (HPC) production. To obtain the properties of the cementitious materials, the chemical composition, mineral phases, morphology, calcination efficiency and physical properties were quantitatively analysed using the advanced techniques of X-ray fluorescence (XRF), scanning electron microscopy/energy dispersive X-ray (SEM/EDX), X-ray diffraction (XRD), Fourier transform infrared/attenuated total reflection (FTIR/ATR), thermogravimetric analysis (TGA), laser particle sizing and Brunauer–Emmett–Teller (BET) nitrogen absorption method. The MCC’s effect on the workability and mechanical properties (compressive, splitting tensile and flexural strengths) and microstructure (morphology and crystalline phases) of hardened MCC-based HPCs were determined. The XRF result shows that the oxide composition of MCC confirmed the pozzolanic material requirements with recorded high useful oxides content. At the same time, the SEM image presents particles of broad, solid masses with a wider surface area of irregular shape. The XRD results show that the MCC was majorly an illite-based clay mineral calcined at a maximum temperature of 650 °C, as revealed by the TGA. The MCC addition increases the slump flow of HPCs at 5–15% cement replacement. The MCC incorporation at 10% cement replacement best improved the porosity of HPCs at a later age resulting in increased mechanical and microstructural properties of tested samples. Therefore, it is recommended that MCC addition within 10% cement replacement be adopted for low W/B Class I HPC at no deleterious results on mechanical and microstructural properties of the concrete.},

keywords = {dehydroxylation, high-performance concrete, meta-illite calcined clay, superabsorbent polymers, superplaticiser, Supplementary cementitious materials},

pubstate = {published},

tppubtype = {article}

}