scholarly journals Effectiveness of Calcium Carbonate Whisker in Cementitious Composites

Author(s):  
Mingli Cao ◽  
Mehran Khan ◽  
Shakeel Ahmed

Cementitious composites are porous material having complex structure system consist of hydration products, un-hydrated cement particles and pore solutions of various scales. Calcium carbonate whisker is a new type of low cost micro-scale filler fiber gaining popularity in the field of construction materials. However, addition of whisker has effect on physical, mechanical and microstructural characteristics of cementitious composites. Also, the low production cost of whisker will make the use of micro fiber more extensive in large scale construction projects. In this study, the effect of calcium carbonate whisker on physical, mechanical and microstructural properties of cementitious composites with different fiber contents are investigated. The fluidity, drying shrinkage, pore structure, impact resistance, compressive, flexural and splitting-tensile strength of whisker-mortar are considered. The scanning electron microscopy analysis is also performed to examine the microstructural and toughening mechanism of whisker reinforced composites. It was concluded that the addition of calcium carbonate whisker up to 10 % improves the physical and mechanical properties of cementitious composites and is suggested to be the optimize content. The calcium carbonate whisker also resists the crack propagation at micro scale and showed the toughening mechanism with better interfacial properties between whisker and matrix.

Author(s):  
Daniel Zawal ◽  
Krzysztof Górski ◽  
Agnieszka Dobosz

Biodeterioration of construction materials is an undesired phenomenon, generating high costs of constraction repairs. On the other hand, occurrence of some bacteria can affect prevention and self repair of fractures formed in concrete. Biodeposition is an effective solution for increasing compressive strength of concrete, extending durability of concrete constructions and renovating limestone elements in facades of historic buildings.


2019 ◽  
Vol 31 (11) ◽  
pp. 2522-2526
Author(s):  
S. Seesanong ◽  
C. Laosinwattana ◽  
K. Chaiseeda ◽  
B. Boonchom

This study was designed to manage golden apple snail shells, the wastes created in large amount daily from the consumption of the meat of golden apple snail (Pomacea canaliculata) shells by transforming them to advanced compounds; calcium carbonate (CaCO3), monocalcium phosphate monohydrate [Ca(H2PO4)2·H2O], and tricalcium phosphate [Ca3(PO4)2]. They were successfully prepared by a rapid, simple, environmentally benign method using easily available and low-cost instrument. All synthesized samples were characterized by X-ray fluorescence, X-ray powder diffraction, FTIR spectroscopy and scanning electron microscopy to confirm the identities with the standard materials. The reproducibility and low-cost method suggest that it could be used in industry for a large-scale production of calcium carbonate, monocalcium phosphate monohydrate and tricalcium phosphate from golden apple snail shells as a replacement of natural mineral resources and be a good way to manage these shell wastes.


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Syairah Liyana Mohd Abd Ghafar ◽  
Mohd Zobir Hussein ◽  
Zuki Abu Bakar Zakaria

The development of cockle shell-based calcium carbonate aragonite polymorph nanoparticle synthesis method using the technique of mechanical stirring in the presence of dodecyl dimethyl betaine (BS-12) incorporated with surface functionalization demonstrated high homogeneity of sample product with good nanoparticles dispersion. The cockle shell-based calcium carbonate aragonite nanoparticle with functionalized surface was characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), particle size distribution, pH measurement analysis, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). Surface functionalization was proven to improve the overall size and shape of the nanoparticles and enhance their dispersion properties, preventing coarse agglomeration among nanoparticles in general. The improved method was verified to retain its aragonite crystalline nature. Additionally, surface functionalization did not increase the size of nanoparticles throughout the modification process. This facile preparation using naturally occurring cockle shells as the main source is environmentally friendly because it provides relatively low cost of raw material source as it is abundantly available in nature and has good mineral purity content. Hence, high quality production of surface functionalized cockle shell-based calcium carbonate aragonite polymorph nanoparticles can potentially be exploited and produced on a large scale for various industrial applications, especially for biomedical purposes in the near future.


In this study, an attempt has been taken to utilize the wastes produced from agriculture as a partial replacement to scarce material like fine aggregate in the manufacturing of useful construction materials. Also, Waste Sludge (WS) generated through treatment plant from Kalasalingam Academy of Research and Education was used suitably as one of the ingredients in the manufacturing of construction materials. Various other wastes generated through agriculture such as Banana Fiber (BF), Rice Husk Ash (RHA), and Sugarcane Bagasse Ash (SBA) was also utilized suitably after pre-treatment in the manufacture of tiles and bricks. Five different mixes under various levels of replacement of waste sludge and agricultural wastes were prepared to study its behavioral performance. Various tests conducted to study the performance behavior include Compressive Strength, Water Absorption and Physical Parametric tests on both brick and tile specimens. Results indicate that all physical and mechanical properties of bricks and tiles fall within BIS standards by the combination with a higher percentage of Red Soil,Sugarcane fiber and Waste Sludge.


Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 492
Author(s):  
Mohamed G. Arab ◽  
Rami Alsodi ◽  
Abdullah Almajed ◽  
Hideaki Yasuhara ◽  
Waleed Zeiada ◽  
...  

The global construction industry consumes huge amounts of mined materials that are considered unsustainable for earth resources. In addition, Portland cement which is a key element in concrete and most construction materials is considered one of the main contributors to worldwide CO2 emissions. On the other hand, natural cemented soil deposits are examples of sustainable structures that have survived decades of severe environmental conditions. Mimicking these natural biological systems provide an alternative to the current practices of construction materials production. Enzyme-induced carbonate precipitation (EICP) is a bio-inspired technique based on the precipitation of calcium carbonate for enhancing the geo-mechanical properties of soils. In this technique, calcium carbonate acts as a cementitious agent that binds the soil particles together at the points of contact, hence, increasing the strength and stiffness of treated soils, while relatively reducing the soil permeability and porosity. The achieved enhancements make EICP useful for applications such as ground improvement, construction materials, and erosion control over traditional binders. This paper presents a state-of-the-art review of EICP for ground improvement including the fundamental basics of EICP treatment. The paper also discusses the chemical and physical factors affecting the performance of EICP such as enzyme source, enzyme activity and solution constitutes. Moreover, the paper reviews the different methods and testing techniques used in the application of EICP for soil treatment. Furthermore, the paper compares EICP with other biomineralization techniques in terms of performance and applicability on ground improvement. Finally, the paper discusses the research gaps and existing challenges concerning the commercialization and large-scale implementation of the technology.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhi Li

With the wide application of science and technology in the field of weapons, shock wave is an important breakthrough point in weapon research, and the storage and testing system of shock wave is a breakthrough point that people pay most attention to at present. Shock wave data storage has the characteristics of large scale, complex structure, low cost efficiency, and strong timeliness. This paper mainly studies the design of shock wave storage test system with variable parameters based on numerical piezoelectric circuit sensor. Based on fluid dynamics simulation theory and numerical simulation method, the normal and concave-convex three-dimensional models of two pressure measuring devices are constructed by using the flow waveform of calculator, and then, the network is divided. The results show that, under the same inlet pressure, the larger the bulge or depression value, the greater the influence on the experimental results. The influence of disk is 10% higher than that of pen, and the change rate of relative difference is increased by 1.5% with the increase of concave-convex value. Finally, experiments are carried out in different environments to verify the reliability, survivability, and flexibility. The shock wave storage test system is optimized when the parameters of the digital voltage circuit sensor are variable.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Kh. Nurul Islam ◽  
A. B. Z. Zuki ◽  
M. E. Ali ◽  
Mohd Zobir Bin Hussein ◽  
M. M. Noordin ◽  
...  

A simple and low-cost method for the synthesis of calcium carbonate nanoparticles from cockle shells was described. Polymorphically, the synthesized nanoparticles were aragonites which are biocompatible and thus frequently used in the repair of fractured bone and development of advanced drug delivery systems, tissue scaffolds and anticarcinogenic drugs. The rod-shaped and pure aragonite particles of30±5 nm in diameter were reproducibly synthesized when micron-sized cockle shells powders were mechanically stirred for 90 min at room temperature in presence of a nontoxic and nonhazardous biomineralization catalyst, dodecyl dimethyl betaine (BS-12). The findings were verified using a combination of analytical techniques such as variable pressure scanning electron microscopy (VPSEM), transmission electron microscopy (TEM), Fourier transmission infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), and energy dispersive X-ray analyser (EDX). The reproducibility and low cost of the method suggested that it could be used in industry for the large scale synthesis of aragonite nanoparticles from cockle shells, a low cost and easily available natural resource.


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