Samples concrete

For the analysis heat and mass transfer in concrete samples at high temperatures, the numerical model has been developed. It describes concrete, as a porous multiphase system which at local level is in thermodynamic balance with body interstice, filled by liquid water and gas phase. The model allows researching the dynamic characteristics of diffusion in view of concrete matrix phase transitions, which was usually described by means of experiments. 

As a final application of the profiling technique, the sensor for large depth measurements described in Section 2.4.2.5 was used to resolve multi-layer polymer coatings on concrete samples. Such coatings are used to protect concrete from degradation and corrosion. They are applied to the concrete surface to reduce the porosity in the upper first millimeters to prevent the penetration of water and... 

The device for examination of gas permeability of samples of constructive materials has been constructed. The device consists of compressor 1, receiver 2 with manometer 3, gates 4,5, holder 6 of concrete samples 7, flow meter of air 8 and vessel with gas 9 (Fig.l). The gate 5 adjusted the value of the gas pressure. In all experiments the pressure of gases in the receiver was 110 kPa. Air, Ar and 222Rn with concentration of 100 pCu/L in air were used as the gases. 

SP 8 Recommended operating procedure for the preparation of concrete samples... 

The concrete sample from the organic extraction or a new portion of 10 g of the original sample is then extracted with distilled, deionized water in the manner described above for organic solvent (Figure 4, fraction 2). This sample is analyzed for polar CWC-related chemicals. For analysis with GC and GC-hyphenated techniques, the water extract must first be derivatized an appropriate part of the extract is evaporated to dryness on a rotary evaporator at 50 °C and 366 mPa for ca. 30 min, and then 0.5 ml of acetonitrile and 0.5 ml of BSTFA are poured over the evaporation residue and the silylation mixture is heated at 60 °C for 30 min to complete the silylation (Figure 4, fraction 2A). This... 

Figure 4. Schematic presentation of the recommended operating procedure for concrete sample preparation...

An appropriate portion of the HC1 extract of the concrete sample is prepared for analysis of the sample for lewisite 1, lewisite 2, and lewisite oxide (Figure 4, fraction 3B). The pH of the sample is adjusted with hydrochloric acid to pH 2, the sample is filtered, and 0.1 ml of a freshly prepared solution containing DMT 5 mg ml-1 in acetone is added. The sample vial is shaken vigorously and then allowed to stand for 10 min. After addition of 1 ml of n-hexane, the sample is shaken vigorously for 30 s every 10 min for 30 min. The hexane fraction is allowed to separate. The top hexane-water layer is transferred to a new vial and centrifuged. After centrifugation, the hexane fraction is separated, dried, and submitted for analysis. 

Concrete samples Paint samples ROPs were established... 

The results obtained from tests on carbon steel and stainless steels on exposure to 0.5 and 2% chloride for period of two years at 80% relative humidity are noted in Table 7.13. It is obvious from the data that carbon steel failed in 2% chloride along with severe cracking of the concrete sample. The stainless steels did not corrode and the concrete also remained intact without cracking. 

Figure II. Compressive strength of sulfur concrete samples made with basalt and granulit aggregate vs. the DCP content...

Figure 12. Compressive strength vs. flexural strength of sulfur concrete samples with different DCP content in the binder...

Figure 13. Influence of the storage time on the compressive and flexural strength of DCP-modifled sulfur concrete samples.

Hooton (H48) noted some pitfalls in the experimental determination of permeabilities and in the practical utilization of the results. In an experimental determination, accurate results will not be obtained unless the sample has been vacuum saturated and, even if it is, equilibrium flow in accordance with d Arcy s law may not occur because water is being used up to continue hydration. In practice, a concrete sample is probably not often saturated throughout if it is not, capillary forces, as well as the pressure difference. alTect the rate of flow. Applications of results obtained with pastes to concrete are further complicated by the presence in the latter of cracks, poorly compacted areas and other inhomogeneities. 

The method decontamination factors were determined using additions of Fe, Ba, Cs, Eu, Co and Ni (all eommonly found in activated concrete samples). The final fraetion was analysed by ICP-MS and ICP-AES, showing that the decontamination factors for Fe and Ni were > 10", and for Co, Cs and Eu were > 10. The decontamination factor for Ba was only 7, implying that the Mn02 resin was saturated with Ba during this proeedure. From the known Ba content of the concrete and the amount added it was caleulated that for this method test with a complex sample matrix the loading capacity of the Mn02 resin for Ba was 212 pg Ba / g resin. 

Tomczynska, J., Blaton-Albicka, K., Pensko, J. et al.. The results of measurements of the natural radionuclides in coal power plants wastes and light concrete samples. Nukleonika, Warsaw, 1981. 

No noticeable segregation of the mix was found to be produced by the fillers. In fact, the cohesiveness of the mix was greatly improved with vent dust. During the mixing of the many batches none of the plastic fillers was observed to flow to the top. An analysis of the concrete samples showed that the mixing procedure had evenly distributed the plastic chips. 

A proposed impact test using concrete cubes in the Los Angeles abrasion machine proved to be an effective way for testing the resistance of concrete subjected to repetitive low impact loading. Only HDPEfme improved the impact resistance of concrete. The impact resistance of concrete was not affected with the incorporation of PET and PS flakes. Vent dust reduced the impact resistance of the concrete samples for both content levels. 

Chloride ion detection for corrosion monitoring. Tang and Wang [40] measured chloride ions in a typical concrete sample immersed in saltwater solutions with different weight concentrations ranging from 0% to 25%. The LPG sensor exhibited a linear decrease in the transmission loss and resonance wavelength shift when the concentration increased. The measurement accuracy for the concentration of salt in water solution was estimated to be 0.6% and the limit of detection for chloride ions was about 0.04%. 

Oxygen and carbon isotopic analyses were made on 166 concretion samples, 34 host rock samples, 54 calcite-cemented beds, 33 veins and 38 mudrock samples. Samples were reacted with 100% phosphoric acid at 25 °C and the extracted gases were analysed on a VG Prism gas-source mass spectrometer. Isotopic values (machine reproducibility 0.02%o are reported relative to the pdb standard. 

Polymer concrete samples of four compositions (Table 1.2) measuring 4 x 4 x 16 cm are prepared. Control samples were placed in a desiccator containing moisture absorption silica gel composition. Other samples were in environments with various humidity. The influence of environmental humidity on the compressive strength, modulus elasticity, and moisture absorption of furfurol-acetone, epoxy, polyester, and rubber (RubCon) polymer concrete samples are shown in Tables 1.3-1.5 and Figures 1.4 and 1.5. 

Composition of the Polymer Concrete Samples (weight parts)... 

Deformation properties of the furfurol-acetone polymer samples are reduced to a much greater extent. The modulus of elasticity of the polymer concrete samples starts to decrease noticeably (about 10% to 15%) at 50% to 95% humidity after just 150 days for the samples in water, a 30% reduction of the modulus has been observed after 50 days (Figure 1.7). After 350 days, the modulus of elasticity is reduced by 28% for the samples in the environment with 50% to 60% humidity, 46% in the medium with 85% to 95% humidity, and 67% for the samples stored in water. As this takes place, the trend of modules is not identical the modulus of elasticity of the first two series of samples trends downward over time, whereas for the samples in water, this tendency stopped after 6 months of exposure. 

It is apparent that a water environment is a limiting case. As this takes place, the ultimate compressive strength and the module of elasticity of polymer concrete samples decreased accordingly, up to 44,000 and 63,000 MPa. 

FIGURE 1.6 Dependence of ultimate compressive strength of furfurol-acetone polymer concrete samples on exposition time at humidity of environment 1 50%-60%, 2 85%-95%, 3 water immersion. (From Yu. Borisov, Yu. Potapov, O. Figovsky, D. Beilin, Water Resistance of the Polymer Concretes, /. Scientific Israel Advanced Technology 14, no. 3 (2012) 84-91. With permission.)... 

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