Microstructure and durability performance of sustainable cementitious composites containing high-volume regenerative biosilica

Li, Jiaqi; Jin, Qingxu; Zhang, Wenxin; Li, Chen; Monteiro, Paulo J.M.

doi:10.1016/j.resconrec.2021.106038

Cited by 21 publications

(7 citation statements)

References 59 publications

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“…During the hydration of cementitious systems, SCMs play a major role by reducing the calcium-to-silicon ratio of C-S-H while improving the mean silica chain length [10,11]. Their presence in concrete also significantly alters the microstructure by refining the pore structure, making it more dense [12]. SCMs are essential materials in cementitious systems for controlling the physical and chemical properties and, consequently, their mechanical and durability performance.…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical Characterisation of Calcined Impure Kaolinitic Clay as a Composite Binder in Cementitious Mortars

et al. 2022

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The availability of some supplementary cementitious materials, especially fly ash, is of imminent concern in Europe due to the projected closure of several coal-fired power generation plants. Pure kaolinitic clays, which arguably have the potential to replace fly ash, are also scarce and expensive due to their use in other industrial applications. This paper examines the potential utilisation of low-grade kaolinitic clays for construction purposes. The clay sample was heat-treated at a temperature of 800 °C and evenly blended with Portland cement in substitutions of 10–30% by weight. The physical, chemical, mineralogical and mechanical characteristics of the blended calcined clay cement were determined. The Frattini test proved the pozzolanic potential of the calcined impure clay, as a plot of its CaO and OH− was found below the lime solubility curve. The 28 days compressive strengths trailed the reference cement by 5.1%, 12.3% and 21.7%, respectively, at all replacement levels. The optimum replacement level between the three blends was found to be 20 wt.%.

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Section: Introductionmentioning

confidence: 99%

Mechanochemical Characterisation of Calcined Impure Kaolinitic Clay as a Composite Binder in Cementitious Mortars

et al. 2022

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“…(e) 10,000× Magnification In all the samples, the cubic crystals typical of portlandite are missing. This could be mainly due to the pozzolanic reaction, S + H2O + CH → C-S-H, which takes place in a paste with a cement rich in silica [7], besides an early limited amount of surface carbonization. This ensures that the pozzolanic reaction can continue every time the mortar comes into contact with water or condensed moisture.…”

Section: Mortar With a Crystallization Admixturementioning

confidence: 99%

“…There is always a growing demand for impermeable concrete for building hydraulic structures, such as channels and dams, and for water containment generally [1,2]: the more impermeable the concrete, the more durable the structure. Although it may not be enough to prevent degradation in chemically aggressive environments [3][4][5][6][7], using impermeable concrete can reduce the degradation rate, and the associated maintenance costs and energy consumption. According to the norms and standards, a concrete structure is designed taking into consideration its nominal service life (which depends on the type of structure and environmental factors) and specifying an appropriate level of concrete permeability [8].…”

Section: Introductionmentioning

confidence: 99%

Porosity of a Fast-Setting Mortar with Crystallization Admixture and Effect of a SA-PA Modification

et al. 2022

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Air permeability measurements according to the Hagen–Poiseuille equation, Scanning Electron Microscopy (SEM) and mercury intrusion porosimetry (MIP) tests were conducted on samples of cementitious mortar at different curing times to study the correlation between the increased crystallization and their microstructure. The mortar samples were prepared with a commercial fast-setting premix containing calcium silicates and quartz. The average permeability coefficient (K) was 2.96 × 10−15 m2 after 3 days and decreased to 3.07 × 10−17 m2 after about one month. The continuous C-S-H nucleation in the capillary pores of the cement mortar changes their shape and improves the mortar’s impermeability. The SEM images showed the development of crystals that refine the pore size distribution of the cement paste, with more of the smallest pores, and fewer of the largest, as demonstrated by the MIP measurements. Adding a superabsorbent polyacrylate (SA-PA) in the amount of 0.5% wt of dry powder, without adding any extra water, makes a mortar less fluid but not faster-setting. Twenty-four hours after mixing and casting, it is still plastic and, with time, the pore size distribution differs from that of standard mortar. Over time in air, permeability remains high, but in water it could be low due to swelling of SA-PA residues.

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“…Various approaches have been explored to enhance the mechanical properties of cementitious materials, including the incorporation of additives, that can modify the microstructure and hydration characteristics of cement-based systems, thereby influencing their mechanical behavior. A new trend in research is the use of not only microsilica, which is a waste from the metallurgical industry (created during the processing of metallic silicon, ferrosilicon, or other silicon alloys), but also the use of biosilica of biogenic origin or extracted from rice husk ash using the thermochemical method [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Using diatomite (DE) as a reinforcement in cement-based materials has shown promising results [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the inclusion of biosilica particles resulted in a reduction in both the water vapor transmission rate and the setting time of the mortar. In [ 23 ], the researchers investigated the durability performance and underlying methods of DE-containing cementitious composites by partially replacing Portland cement with 30 wt.% diatomite. The results showed that the cementitious materials containing DE biosilica exhibited remarkable impermeability and leaching resistance after 28 days.…”

Section: Introductionmentioning

confidence: 99%

The Use of Biosilica to Increase the Compressive Strength of Cement Mortar: The Effect of the Mixing Method

et al. 2023

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In this work, the effect of biosilica concentration and two different mixing methods with Portland cement on the compressive strength of cement-based mortars were investigated. The following values of the biosilica concentration of cement weight were investigated։ 2.5, 5, 7.5, and 10 wt.%. The mortar was prepared using the following two biosilica mixing methods: First, biosilica was mixed with cement and appropriate samples were prepared. For the other mixing method, samples were prepared by dissolving biosilica in water using a magnetic stirrer. Compressive tests were carried out on an automatic compression machine with a loading rate of 2.4 kN/s at the age of 7 and 28 days. It is shown that, for all cases, the compressive strength has the maximum value of 10% biosilica concentration. In particular, in the case of the first mixing method, the compressive strength of the specimen over 7 days of curing increased by 30.5%, and by 36.5% for a curing period of 28 days. In the case of the second mixing method, the compressive strength of the specimen over 7 days of curing increased by 23.4%, and by 47.3% for a curing period of 28 days. Additionally, using the first and second mixing methods, the water absorption parameters were reduced by 22% and 34%, respectively. Finally, it is worth noting that the obtained results were intend to provide valuable insights into optimizing biosilica incorporation in cement mortar. With the aim of contributing to the advancement of construction materials, this research delves into the intriguing application of biosilica in cement mortar, emphasizing the significant impact of mixing techniques on the resultant compressive strength.

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Microstructure and durability performance of sustainable cementitious composites containing high-volume regenerative biosilica

Cited by 21 publications

References 59 publications

Mechanochemical Characterisation of Calcined Impure Kaolinitic Clay as a Composite Binder in Cementitious Mortars

Mechanochemical Characterisation of Calcined Impure Kaolinitic Clay as a Composite Binder in Cementitious Mortars

Porosity of a Fast-Setting Mortar with Crystallization Admixture and Effect of a SA-PA Modification

The Use of Biosilica to Increase the Compressive Strength of Cement Mortar: The Effect of the Mixing Method

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