Cockle Shell as Mixing Ingredient in Concrete: A Review

The usage of plentiful raw discarded resources in the manufacturing of concrete has proven to be a sustainable and environmentally beneficial method of making concrete for a variety of purposes. In this study, the physical and mechanical properties of concrete made by partially and fully substituting fine aggregates and ordinary Portland cement with periwinkle shell ash and quarry dust (5%, 10%, 15%, 20%, and 100%), respectively, were examined. The ratio of water to cement utilized for the concrete mixture, 1:2:4, was 0.60. Fresh concrete underwent a slump test, and then 150-mm cubes of cured concrete were subjected to density, compressive strength tests, and morphological and structural property characterizations. The concrete without the waste materials gave an optimum compressive strength of 22.9 N/mm2 as opposed to those that were partially replaced, having 18.8–15.1 N/mm2. The concrete samples with full replacements of periwinkle shell ash and quarry dust have compressive strengths lower than 13.8 N/mm2. All the concrete samples produced with partial and full replacements are in the class of normal concrete, but only those with partial replacements of up to 20% can be utilized for load-bearing and non-load-bearing applications. Opting for these alternative waste materials implies taking steps towards creating a cleaner and healthier planet for now and the future.

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Rheology of cement–sodium silicate grout containing bentonite and cellulose ether at high temperatures

Liu

et al. 2023

Advances in Cement Research

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Cement-sodium silicate (C-S) grout is widely used to control water inrush disasters, and its apparent viscosity considerably impacts its water-plugging effect. However, the traditional grouting materials and methods are inappropriate for high-temperature environments, as high temperatures can affect the grout viscosity. Viscosity-modifying admixtures (VMAs) are used to thicken the grout and increase its apparent viscosity. In this study, two types of bentonite (calcium bentonite, Ca-B, and sodium bentonite, Na-B) and hydroxyethyl methyl cellulose (HEMC) were used to modify the C-S grout, and laboratory tests to evaluate fluidity, gelation time, and rheology were performed. The results showed that both bentonite and HEMC decreased fluidity and prolonged gelation time. HEMC, Ca-B, and Na-B decreased fluidity by 46.8–60.4%, 12.5–31.5%, and 17.7–39.1%, respectively, at different temperatures. HEMC, Ca-B, and Na-B increased gelation time by 23.8–50.1%, 23.3–71.4%, and 20%–57.1%, respectively. Additionally, bentonite can partially resist high temperatures and improve the apparent viscosity of grout owing to its water-absorption capacity. Conversely, HEMC has a negative effect on apparent viscosity, which is attributed to the formation of a complex microstructure resulting from intermolecular crosslinking between the cement particles and HEMC, preventing the connection of sodium silicate.

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Cockle Shell as Mixing Ingredient in Concrete: A Review

Cited by 3 publications

References 37 publications

Uncrushed Cockleshell as Coarse Aggregate Filler Replacement in Concrete

Uncrushed Cockleshell as Coarse Aggregate Filler Replacement in Concrete

Utilization of quarry dust and periwinkle shell ash in concrete production

Rheology of cement–sodium silicate grout containing bentonite and cellulose ether at high temperatures

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