Hydration Behavior of Composite Cement Containing Fly Ash and Nanosized-SiO2
H. El-Didamony,
S. Abd El-Aleem,
Abd El-Rahman Ragab
Issue:
Volume 4, Issue 2, March 2016
Pages:
6-16
Received:
11 February 2016
Accepted:
28 February 2016
Published:
17 March 2016
DOI:
10.11648/j.nano.20160402.11
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Abstract: In recent years, there is a great interest in replacing a long time used materials in concrete structure by nanomaterials (NMs) to produce a concrete with novel functions. NMs are used either to replace a part of cement, producing ecological profile concrete or as admixtures in cement pastes. The great reactivity of NMs is attributed to their high purities and specific surface areas. A number of NMs been explored and among of them nanosilica (NS) has been used most extensively. This work aims to study, the hydration behavior of composite cements containing fly ash (FA) and nanosilica. Different cement blends were made from OPC, FA and NS. OPC was substituted with FA up to 30.0 mass, %, then the FA portion was replaced by equal amounts of NS (2.0, 4.0 and 6.0 mass, %). The hydration behavior was followed by determination of free lime (FL) and combined water (Wn) contents at different curing ages. The required water for standard consistency (W/C), setting times (IST & FST), bulk density (BD) and compressive strength were also estimated. Some selected hydration products were analyzed using XRD and DTA techniques. The results showed that, both of FA and NS improve the hydration behavior and mechanical properties of the investigated cements. But, NS possesses higher improvement level than FA, due to that, both of them behaves not only as filler, but also as activator to promote pozzolanic reaction, which enhances the formation of excessive dense products. The higher beneficial role of NS is mainly due to its higher surface area, seeding effect and pozzolanic activity in comparison with FA. The composite cement containing 70.0% OPC, 26.0% FA and 4.0% NS gave the desirable mechanical properties at all curing ages.
Abstract: In recent years, there is a great interest in replacing a long time used materials in concrete structure by nanomaterials (NMs) to produce a concrete with novel functions. NMs are used either to replace a part of cement, producing ecological profile concrete or as admixtures in cement pastes. The great reactivity of NMs is attributed to their high ...
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Physicochemical and Mineralogical Characterization of Moroccan Clay of Taza and Its Use in Ceramic Technology
Issue:
Volume 4, Issue 2, March 2016
Pages:
17-22
Received:
28 January 2016
Accepted:
8 April 2016
Published:
9 May 2016
DOI:
10.11648/j.nano.20160402.12
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Abstract: This study concerns the results of Physicochemical and mineralogical characterization of a white clay located in Taza region in Morocco and its use in the ceramics industry. Several techniques were used; in particular X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential thermal and gravimetric analyses (DTA-TGA) and finally infrared Fourier transform (FTIR) and X-ray fluorescence (XRF). The first objective of this work is to put a new line of research that deals with the use of clay in ceramic technology. The second objective was to develop gels of oxides of high purity from these clays. we can say that the white clay of Taza has the same characteristics of clays used in the ceramics industry (medium heat loss, low shrinkage, good flexural strength and good behavior in plasticity), this white clay Taza adding 0.57% sodium carbonate is sufficient to have a good deflocculation and the viscosity is minimum corresponds to the stability of the slip, in his introduction to a formula of slip was successful with a rate of 35 to 45%. The SEM-EDX, X-ray, chemical analysis and Infrared spectroscopy demonstrated and allowed us to identify the different minerals that make up the white clay, compared with the available data, we identified illite and kaolinite as clay minerals, other minerals present as impurities major are quartz, calcite, dolomite and feldspar. These results show the important features to justify its use in the ceramic industry.
Abstract: This study concerns the results of Physicochemical and mineralogical characterization of a white clay located in Taza region in Morocco and its use in the ceramics industry. Several techniques were used; in particular X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential thermal and gravimetric...
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