Effect of Polymer Additive on Gas Permeability Coefficient of Concrete

2013 ◽  
Vol 687 ◽  
pp. 191-197 ◽  
Author(s):  
Bogumiła Chmielewska
Keyword(s):  
Permeability Coefficient ◽  
Gas Permeability ◽  
Cement Composites ◽  
Polymer Additive ◽  
Concrete Composition ◽  
Concrete Construction ◽  
Technological Characteristics ◽  
Repair Materials ◽  
Mineral Components

Polymer-cement composites are valuable repair materials for concrete construction. Their mechanical and technological characteristics differ from those of materials containing only mineral components. One of the most important properties determining the sustainability of the composite is gas permeability coefficient. The influence of concrete composition on the value of gas permeability coefficient is discussed in the paper. Methods of the coefficient determination are characterized. The paper presents the research on the influence of polymer additive on the permeability coefficient of concrete as compared to the concrete without additive.

Analytical solution and evolution process of gas permeability coefficient on typical hard-soft composite coal seam

2021 ◽  
Vol 14 (15) ◽  
Author(s):  
Yikuo Wang ◽  
Hongbao Zhao ◽  
Tong Wu ◽  
Lei Wang ◽  
Jinyu Li ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Coal Seam ◽  
Permeability Coefficient ◽  
Gas Permeability ◽  
Evolution Process ◽  
Soft Composite

scholarly journals Permeability of Concrete and Correlation with Microstructure Parameters Determined by 1H NMR

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yurong Zhang ◽  
Shengxuan Xu ◽  
Zhaofeng Fang ◽  
Junzhi Zhang ◽  
Chaojun Mao
Keyword(s):  
Water Permeability ◽  
Permeability Coefficient ◽  
Pore Diameter ◽  
Gas Permeability ◽  
Steady State Flow ◽  
Test Device ◽  
Water Permeability Coefficient ◽  
Microstructure Parameters ◽  
The Relationship ◽  
Better Than

Water and gas permeability coefficients of concrete with different water-binder (w/b) ratios and admixtures were measured by a self-designed test device based on the steady-state flow method for liquid and the method of differential pressure in stability for gas, respectively. In addition, the micropore structure of concrete was determined by 1H nuclear magnetic resonance (NMR). Results indicated that there are good correlations between water and gas permeability of concrete with different w/b ratios, with correlation coefficient greater than 0.90. Better correlations between water permeability and segmental contributive porosity ranged from 10 to 100 nm and 100 to 1000 nm can be identified, but the gas permeability is more relevant to the segmental contributive porosity ranging from 100 to 1000 nm. Moreover, the correlation between water permeability and contributive porosity for each pore diameter is always better than that of gas permeability. The influence of admixtures on the relationship between permeability and pore size distribution of concrete is significant. Moreover, water permeability coefficient is one or two orders of magnitude lower than the gas permeability coefficient.

Study on Original Coal Seam Permeability Coefficient

2011 ◽  
Vol 361-363 ◽  
pp. 179-182
Author(s):  
Zi Wen Dong ◽  
Qing Jie Qi ◽  
Nan Hu ◽  
Chang Fu Xu ◽  
Hui Niu
Keyword(s):  
Coal Seam ◽  
Water Flow ◽  
Coal Mine ◽  
Permeability Coefficient ◽  
Gas Flow ◽  
Radial Flow ◽  
Gas Permeability ◽  
Coal Seam Gas ◽  
Flow Method

In the case of gas radial flowing in layer-though boring, use the method of draining water gathering gas measured the Gas flow of borehole that there is water flow out from drilling Sometimes,the coal seam gas permeability coefficient is calculated using"Radial Flow Method"and"Optimizing Method,found out the range of 5-3 original coal seam Hongmiao coal mine permeability coefficient is0.007~0.008 m2/(MPa2·d).

scholarly journals The gas permeability coefficient of the cyanobacterial gas vesicle wall

1992 ◽  
Vol 138 (4) ◽  
pp. 837-845 ◽  
Author(s):  
A. E. Walsby ◽  
N. P. Revsbech ◽  
D. H. Griffel
Keyword(s):  
Permeability Coefficient ◽  
Gas Permeability ◽  
Vesicle Wall

Effect of Rice Husk Ash Fineness on the Properties of Concrete

2014 ◽  
Vol 554 ◽  
pp. 203-207 ◽  
Author(s):  
Sri Jayanti Dewi ◽  
Putra Jaya Ramadhansyah ◽  
Abdul Hassan Norhidayah ◽  
A. Aziz Md. Maniruzzaman ◽  
Mohd Rosli Hainin ◽  
...  
Keyword(s):  
Rice Husk ◽  
Permeability Coefficient ◽  
Rice Husk Ash ◽  
Gas Permeability ◽  
Blended Cement ◽  
Target Strength ◽  
Cement Concrete ◽  
Mechanical Grinding ◽  
Binder Ratio ◽  
Water To Binder Ratio

In the present research, the effect of rice husk ash fineness on the properties of concrete was studied. Eight different fineness grades of rice husk ash were examined. A rice husk ash dosage of 15% by weight of binder was used throughout the experiments. The water-to-binder ratio was 0.49 to produce concrete having target strength of 40MPa at 28 d. Workability, compressive strength and gas permeability tests were carried out to identify the properties of concrete. The results revealed that increasing the fineness of RHA by mechanical grinding was found to improve the workability of RHA blended cement concrete. In addition, the use of RHA3 with mean particle size of 9.52μm produces the concrete with good strength. Finally, significant improvement was observed in mixtures incorporating RHA in terms of permeability coefficient.

Lower limit of the gas permeability coefficient of gas vesicles

1984 ◽  
Vol 223 (1231) ◽  
pp. 177-196 ◽  
Keyword(s):  
Permeability Coefficient ◽  
Critical Pressure ◽  
Gas Permeability ◽  
Aqueous Suspension ◽  
Pressure Rise ◽  
Gas Pressure ◽  
Gas Vesicles ◽  
Minimum Diameter ◽  
Vesicle Wall ◽  
The Difference

The gas vesicles found in various planktonic prokaryotes are hollow, rigid structures permeable to gases. They collapse when the difference between the external hydrostatic pressure and internal gas pressure exceeds their critical pressure (usually about 0.6 MPa). It was found that dried gas vesicles would survive exposure to gas pressures considerably in excess of this value (4 MPa or more), because gas diffused into them as the pressure was raised and the pressure difference required to cause collapse was not established. They survived the most rapid rates of pressure rise, 0–4.6 MPa in less than 2.5 ms, to which they were exposed. From this it can be calculated that the gas permeability coefficient of the average gas vesicle ( α ) exceeds 22 x 10 3 s -1 and the permeability of the gas vesicle wall ( k ) is greater than 332 μm s -1 . Gas molecules may diffuse through fixed pores in the gas vesicle wall. Since a gas molecule of collision diameter 0.63 nm is known to penetrate the gas vesicle, this would be the minimum diameter of such a fixed pore. It is shown by kinetic theory that the permeability coefficient of an average gas vesicle with one pore of this size would be 2.1 x 10 3 s -1 : there would, therefore, have to be at least 11 such pores to account for the observed minimum permeability coefficient. Gas vesicles in aqueous suspension will also survive a rapid rise in the overlying gas pressure in excess of their critical pressure if they are near enough to the gas-water interface for sufficient gas to reach them by diffusion during the pressure rise. The distance from the interface at which the gas vesicles survive can be used to calculate the diffusivity of the gas through the suspension. A modification of this method can be used to measure the gas-permeability of certain types of cells containing gas vesicles.

Strength and permeability properties of concrete containing rice husk ash with different grinding time

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Ramadhansyah Jaya ◽  
Badorul Bakar ◽  
Megat Johari ◽  
Mohd Ibrahim
Keyword(s):  
Rice Husk ◽  
Permeability Coefficient ◽  
Rice Husk Ash ◽  
Gas Permeability ◽  
Concrete Strength ◽  
Partial Replacement ◽  
Curing Time ◽  
Concrete Permeability ◽  
Different Grain Size ◽  
Grinding Time

AbstractThe compressive concrete strength and the gas permeability properties over varying fineness of the rice husk ash were experimentally investigated. The relationships among them were analyzed. In this study eight samples made from the rice husk ashes with a different grain size were used, i.e. coarse original rice husk ash 17.96 μm (RHA0), 10.93 μm (RHA1) 9.74 μm (RHA2), 9.52 μm (RHA3), 9.34 μm (RHA4), 8.70 μm (RHA5), 6.85 μm (RHA6) and 6.65 μm (RHA7). The ordinary Portland cement was partially replaced with the rice husk ash (15 wt%). The test results showed that the RHA3 produced the concrete with good strength and low porosity. Additionally the strength of the concrete was improved due to the partial replacement of RHA3 material in comparison with normal coarse rice husk ash RHA0. On the other hand the influence of OPC and RHA materials on the concrete permeability was affected by the grinding time and age (i.e., curing time). The permeability coefficient decreased with the increasing of curing time. The relationships between compressive strength and permeability coefficient are greatly affected by curing times and are sensitive to the grinding cementitious systems.

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