The exhalation of radon from concrete blended with silica fumes and fly ash depends upon addition level, porosity, moisture and radioactivity content. In order to optimize the level of substitution of silica fumes and fly ash, measurements of radon exhalation rates from the concrete blended with different proportions of fly ash and silica fumes was carried out using active scintillation radon monitor.
4DCASES video photos photo image picture pics gif
The effect of porosity, moisture, back diffusion and radioactivity content of the concrete on exhalation rates is studied. The measured exhalation rates were extrapolated for indoor radon concentration and effective dose equivalent using ICRP, recommendations. Full Text Available The effect of adding fumed silica and hydroxy apatite to Radiation Vulcanized Natural Rubber Latex RVNRL for improving tear strength, aging properties, degradability and water-soluble protein content of rubber films has been investigated.
The addition of fumed silica and hydroxy apatite in RVNRL improves tear strength and aging properties of rubber films, whereas tensile strength and degradability of rubber films were unchanged during storage at room temperature.
How to make a screenshot or capture in a Y17
The water-soluble protein content in rubber films was reduced by immobilization of the fumed silica and hydroxy apatite and enhanced by addition of ZnO. This may reduce allergy problems of natural rubber latex products caused by water-soluble protein. The MST of the RVNRL with fumed silica and hydroxy apatite indicated that the latex must be used within two months after mixing because of its stability.
Effect of silica fume on reaction products of uranium VI with portland cement. Investigations on the tensile strength of high performance concrete incorporating silica fume. Though the literature is rich in reporting on silica fume concrete the technical data on tensile strength is quite limited. The present paper is directed towards developing a better understanding on the isolated contribution of silica fume on the tensile strengths of High Performance Concrete. Extensive experimentation was carried out over water-binder ratios ranging from 0.
For all the mixes compressive, flexural and split tensile strengths were determined at 28 days. The results of the present investigation indicate that silica fume incorporation results in significant improvements in the tensile strengths of concrete. It is also observed that the optimum replacement percentage, which led to maximization of strength, is not a constant one but depends on the water- cementitious material ratio of the mix. Compared to split tensile strengths, flexural strengths have exhibited greater percentage gains in strength.
For the present investigation transgranular failure of concrete was observed which indicate that silica fume incorporation results in significant improvements in the strength of both paste and transition zone. Influence of polyacrylic ester and silica fume on the mechanical properties of mortar for repair application. Full Text Available Experimental investigations on the influence of different amounts of polyacrylic ester and silica fumes on the mechanical properties of mortar such as the compressive strength, splitting tensile strength, bonding strength, and abrasion resistance are presented in this article.
The results show that the compressive and splitting tensile strength of mortar can be improved with the addition of polyacrylic ester and silica fumes. Results obtained from both the direct tensile bond test and flexural bond test indicate that the addition of polyacrylic ester and silica fumes improves the bond strength significantly, and the enhancement is more obvious with polyacrylic ester paste as interfacial adhesives. Furthermore, mortar incorporation of polyacrylic ester and silica fumes shows superior abrasion resistance compared to the control mortar.
Therefore, the correct combination of polyacrylic ester and silica fumes to produce mortars has been shown to have synergistic effects, which results in excellent properties including high bond strength and superior abrasion resistance. Mortars containing polyacrylic ester and silica fumes are ideal for repairing concrete especially for hydraulic concrete structure. Silica fume is commonly used to increase the mechanical properties of concrete materials and it is also chosen due to certain economic reasons.
The improvement of mechanical properties was due to a significant densification in the microstructure of the cement paste matrix in the presence of silica fume hybrid supplementary binder as observed from micrographs obtained in the study. The overall results showed that there is a potential to utilize silica fume in foamed concrete, as there was a noticeable enhancement of thermal and mechanical properties with the addition of silica fume. Upgrading offshore pipelines concrete coated by silica fume additive against aggressive mechanical laying.
Studies have been carried out to investigate the possibility of utilizing a broad range of micro- silica partial additions with cement in the production of concrete coating. This study investigated the strength properties and permeability of micro- silica concrete to achieve resistance toward concrete cracking and damage during laying. In this work, thermal condensation of alanine adsorbed on fumed silica nanoparticles is investigated using thermal analysis and multiple spectroscopic techniques, including infrared IR , Raman, and nuclear magnetic resonance NMR spectroscopies.
Spectroscopic results further show that alanine is converted to alanine anhydride with a yield of After comparing peptide formation on solution-derived colloidal silica nanoparticles, it is found that fumed silica nanoparticles show much better efficiency and selectivity than solution-derived colloidal silica nanoparticles for synthesizing alanine anhydride.
Furthermore, Raman spectroscopy provides evidence that the high efficiency for fumed silica nanoparticles is likely related to their unique surface features: the intrinsic high population of strained ring structures present at the surface. This work indicates the great potential of fumed silica nanoparticles in synthesizing peptides with high efficiency and selectivity.
Pozzolanic materials, such as fly ash FA , silica fume SF , and blast furnace slag BFS are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis PGNAA technique.
Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. Particularly for chlorine detection using 6. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.
An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration MDC of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement.
Formulation and characterization of date palm fibers mortar by addition of silica fume.
19 June 12222
This paper presents the results of experimental investigations of the formulated and characterization of date palm fibers mortar by addition of silica fume. The use of addition mineral is widely used in the production of cements through the world. The objective of this work is to bring our contribution to the recovery of local resources in the occurrence vegetable fibers of date palm to weak cost and from renewable source and integrate it in the filled of building.
Date palm fiber are from Ouargla town in south of Algeria. The mechanical characteristics compressive and flexural strength of date palm fibers mortar by treatment of the matrix by the adding of silica fume were examined.
All That Has Happened In Technology In the Last 24 Hours
The results obtained have shown that the mortar workability as well as the compressive and flexural strength decreases with increasing the silica fume replacement. The results showed that the use of silica fume enabled to evaluate the flexural strength. However, another treatment of fibers and matrix will be recommended for Improved the characteristics. In situ polymerization of L-Lactide in the presence of fumed silica. Chemiorheology, i.
LA BOLSA CON FONDO DE FIRMEZA
L-Lactide, containing fumed silica have been studied. For that purpose, the reaction was proceeded in situ between the plates of a dynamic rheometer. The polymerization kinetics was followed from the variation of the complex shear modulus versus reaction time. Moreover, at temperatures lower than the crystallization temperature, it was possible to follow the crystallization process while the polymerization takes place. Adding fumed silica particles into the monomer leads to the formation of a physical percolated network from particle-particle interactions, i. The gel-like structure was kept while the polymerization as long as the strain remains low indicating that the silica particle network remains weak.
Furthermore, the mechanism of the break down of the gel structure under large deformation as well as the recovery was discussed. It seems that the non-linearity effect of the nanocomposites stems in the silica inter-particle interactions.
- Screenshot in vivo S1 Pro!
- where to buy a location cell Nokia 7.2;
- SMS location for Redmi;
- Author Details.
It was found that silica particles do not have any effect on the temperature of crystallization - molar mass relation but could act as nucleating agent. In situ polymerization of L-Lactide in the presence of 5 wt. It was found that fumed hydrophilic silica leaded to a microcomposite with highly dense agglomerates in the polymer matrix whereas with a less hydrophilic silica it was possible to decrease the size of the agglomerates increasing the dispersion.
The finest dispersion state was achieved with the 'initiating' functionalized silica leading to a 'grafting from' polymerization of the L-Lactide. Such functionalized silica leads to a nanoscale dispersion in a one-step bulk polymerization with only a few small agglomerates. Prebe, A. Thermogravimetric analyses and mineralogical study of polymer modified mortar with silica fume. Full Text Available Mineral and organic additions are often used in mortars to improve their properties.