scholarly journals Analytical solutions of water suction and drying processes vs. experiments

2020 ◽  
Vol 172 ◽  
pp. 04009
Author(s):  
Peter Matiasovsky ◽  
Peter Mihalka
Keyword(s):  
Water Absorption ◽  
Building Materials ◽  
Drying Rate ◽  
Initial Water Content ◽  
Initial Water ◽  
Water Absorption Coefficient ◽  
Capillary Suction ◽  
Calculation Results ◽  
Important Correlation ◽  
Analytical Expressions

The set of 25 inorganic porous building materials was put through the cumulative water inflow and drying tests in laboratory conditions. Besides these experiments the parameters, including pore structure parameters of the tested materials have been determined. The characteristics of the capillary suction induced water absorption – the water absorption coefficient, and drying – the initial constant drying rate, were compared with their analytical expressions. The results of this analysis show the measure of particular material parameters and boundary conditions significance for the coincidence of experimental and calculation results. At the drying an important correlation between experimentally obtained initial water content and drying rate was observed.

Ermittlung der Kapillartransportkoeffizienten mineralischer Baustoffe aus dem w-Wert / Estimating the capillary transport coefficients of mineral building materials from the water absorption coefficient

1997 ◽  
Vol 3 (3) ◽  
pp. 219-234
Author(s):  
M. Krus ◽  
A. Holm ◽  
Th. Schmidt
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Building Materials ◽  
Transport Coefficients ◽  
Capillary Transport ◽  
Water Absorption Coefficient ◽  
Standard Material ◽  
Moisture Balance ◽  
Computer Calculations ◽  
Building Components

Abstract Computer calculations are of increasing importance for the assessment of moisture balance in building components, since modern calculation methods achieve good agreement with measurements. A broader application of these methods is hampered, however, by the laborious measurements needed to determine the capillary transport coefficients essential for the calculations. A new method is therefore presented which allows to estimate the coefficients from wellknown standard material properties (free capillary saturation, practical moisture content and water absorption coefficient). These coefficients are sufficient for estimative assessment of the moisture balance of many materials, as is demonstrated by comparison of suction profiles calculated in this way and measured profiles.

The Influence of Dehumidifying Condition on Expansive Soil Engineering Properties

2012 ◽  
Vol 594-597 ◽  
pp. 487-492
Author(s):  
Xiong Wei Li ◽  
Ai Jun Wang ◽  
Guo Zhong Dai
Keyword(s):  
Shear Strength ◽  
Relative Humidity ◽  
Water Content ◽  
Expansive Soil ◽  
Expansion Ratio ◽  
Soil Samples ◽  
Engineering Properties ◽  
Drying Rate ◽  
Initial Water Content ◽  
Initial Water

The expansive soil behaviour of expansive deformation and shear strength is deeply influenced by humidity condition. Different soil drying rate was set with constant temperature and different relative humidity. When saturated soil samples was dried to the different predetermined water content, the expansion ratio test with the upper load was made. It is shown that in the condition of high relative humidity, the expansion ratio is high. The smaller initial water content and upper load may lead to a larger swelling deformation. When soil samples with different initial water content was fully expanded, the consolidated direct shear tests were made. It is shown that the smaller drying rate leads to the greater shear strength after full expansion. What’s more, the upper load may improve the soil shear strength.

Evaluation of Incorporation of Dregs in Mortar Production in Replacement of Hydrated Lime

2016 ◽  
Vol 881 ◽  
pp. 351-356
Author(s):  
Rodrigo Felipe Santos ◽  
Rita de Cássia Silva Sant’Ana Alvarenga ◽  
Beatryz Cardoso Mendes ◽  
José Maria Franco de Carvalho ◽  
Leonardo Gonçalves Pedroti
Keyword(s):  
Experimental Design ◽  
Absorption Coefficient ◽  
Water Absorption ◽  
Hydrated Lime ◽  
Quadratic Model ◽  
Lattice Method ◽  
Water Absorption Coefficient ◽  
Capillary Suction ◽  
Model Adjustment ◽  
Simplex Lattice

The dregs is a residue from the cellulose production, and finding new ways to use it would be interesting to reduce environmental impacts. This study aimed at incorporating it into mortar mixture ratios to replace the hydrated lime. Different proportions of cement, sand and dregs were evaluated using the Simplex-Lattice method of experimental design, and it was analyzed water absorption coefficient, compressive strength and flexural strength. The model adjustment was made with seven points plus three axial points and in terms of pseudo-components. A linear model was adjusted for the first characteristic, and a quadratic model for the second and third characteristics. Larger rates of capillary suction and smaller resistance values were noticed with a larger amount of dregs. This experimental design proved feasible, allowing the obtainment of mixture ratios from pre-determined values of water absorption coefficient and resistance, and making more objective the addition of dregs to mortar mixtures.

scholarly journals Built Heritage Evaluation: Manual Using Simple Test Methods

2021 ◽  
Author(s):  
A. Elena Charola ◽  
Jorge Otero ◽  
Paula T. DePriest ◽  
Robert J. Koestler
Keyword(s):  
Water Absorption ◽  
Building Materials ◽  
Test Methods ◽  
Capillary Water ◽  
Laboratory Methods ◽  
Water Absorption Coefficient ◽  
Built Heritage ◽  
Widespread Availability ◽  
Cultural Monuments

<p>This manual describes simple tests for evaluating the condition of built heritage and cultural monuments. The tests were selected for their simplicity and widespread availability, especially in countries where few institutions deal with the conservation of <a>important buildings or monuments</a> and where laboratories capable of the necessary analyses are scarce.</p> <p>Most tests can be carried out without the resources of a complete conservation laboratory. Methods include microscopy, ion test strips, the Scotch Tape test, RILEM tube water absorption, water vapor transmission, and three tests that can be run sequentially: capillary water absorption coefficient, total immersion, and evaporation curves.</p> <p>Some of these tests aid in the examination of building materials and the characterization of salts and other condition problems, which will help to determine the appropriate methods and materials for conservation and restoration.</p>

scholarly journals Penentuan Konstanta Laju Pengeringan Coconut Chips

2021 ◽  
Vol 7 (1) ◽  
pp. 39-49
Author(s):  
Hary Kurniawan ◽  
Sukmawaty Sukmawaty ◽  
Ansar Ansar ◽  
Kurniawan Yuniarto ◽  
Murad Murad ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Rate Constant ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Drying Rate ◽  
Initial Water Content ◽  
Thermogravimetric Method ◽  
Initial Water

This study aims to determine the drying rate constant of coconut chips using an oven. Coconut chips drying is carried out at drying temperatures of 50 ° C, 60 ° C and 70 ° C. Drying coconut chips has been conducted at an initial water content of 40-50% wb until it reached ± 10% wb. The change of moisture content was measured every 15 minutes, and the measurement of the water content was determined by the thermogravimetric method. Newton's model was used in determining the observation drying rate constant. Furthermore, the observation drying rate constant was applied to predict the drying rate constant as a function of temperature using the Arrhenius equation. The results showed that the predicted drying rate constants ranged from 0.0090 - 0.0130 minute-1. 

scholarly journals Crack Evolution Characteristics and Cracking Mechanism of Red Beds in Central Sichuan during Seepage and Swelling

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Zhe Zhou ◽  
Shanxiong Chen ◽  
Yinhui Wang ◽  
Zhangjun Dai
Keyword(s):  
Water Absorption ◽  
Water Content ◽  
Rapid Development ◽  
Development Stage ◽  
Initial Water Content ◽  
Absorption Method ◽  
Initial Water ◽  
Evolution Characteristics ◽  
Cracking Mechanism ◽  
Final Crack

Crack is one of the important factors affecting the engineering characteristics of expansive rock and soil. In order to study the evolution characteristics and cracking mechanism of red beds in Central Sichuan during seepage and swelling, multiple groups of cracking tests are conducted under different initial states with a self-made device. In addition, combining swelling-softening mechanism of expansive rock and numerical analysis, the swelling-cracking mechanism is studied. The following research results are obtained. (1) The evolution process of swelling cracks is divided into three stages: the generation stage, the rapid development stage, and the stabilization stage. In the rapid development stage, the increase in the crack degree accounts for 90% of the whole process. (2) The final crack degree of the sample is related to the initial water content, water absorption method, and clay mineral content. The lower the initial water content, the greater the final crack degree of the sample. The final crack degree under the soaking water absorption method is greater than that under the capillary water absorption method, and the final crack degree of mudstone is greater than that of argillaceous sandstone and sandstone. (3) The development of swelling cracks is controlled by three significant values of water absorption, which are w 1 , w 2 , and w 3 , respectively, representing the beginning of cracking, the starting of the rapid development stage, and the starting of the stabilization stage. Among them, w 2 is of great significance in engineering practice. It shows that the development of cracks has entered a stage of rapid development, and the crack degree in this stage will increase exponentially with water absorption. (4) Uneven water absorption and uneven distribution of clay minerals lead to uneven swelling of expansive rock, which in turn generates swelling stress. Under the combined action of swelling stress and water swelling-softening, the internal structure of the rock is destroyed, leading to the generation and development of the cracks. Due to the different causes of uneven expansion, the mechanical mechanism of cracking and the shape of the resulting cracks will be different.

scholarly journals Kajian Proses Pengeringan Pinang Muda (Areca catechu L) Menggunakan Bahan Bakar Biomassa Kayu : Studi Kasus PT. Areca Agro Aceh

2020 ◽  
Vol 4 (4) ◽  
pp. 522-531
Author(s):  
Cut Nazila Fitri ◽  
Indera Sakti Nasution ◽  
Raida Agustina
Keyword(s):  
Water Content ◽  
Biomass Fuel ◽  
Drying Rate ◽  
Initial Water Content ◽  
Areca Nut ◽  
Wood Biomass ◽  
Initial Water ◽  
Areca Catechu ◽  
Final Water Content ◽  
Air Flow Velocity

Abstrak. Pengeringan pinang muda menggunakan bahan bakar biomassa kayu dapat dilakukan dengan cara pengovenan. Pengeringan dilakukan sebanyak 3 kali pengulangan pada suhu 60oC, perhitungan masa pinang diukur tiap 3 jam untuk 24 jam pertama, tiap 6 jam untuk hari ke-2 sampai sampai massa bahan konstan. Parameter penelitian untuk mengetahui pinang kering berdasarkan perubahan bobot bahan dan kadar air meliputi laju pengeringan, kecepatan aliran udara, kelembaban udara, suhu dan perubahan berat bahan.Hasil penelitian pada PT. Areca Agro Aceh dalam proses pengeringan pinang muda kering dengan menggunakan bahan bakar biomassa kayu menghasilkan rata-rata kelembaban udara sebesar 56% dengan kecepatan aliran udara rata-rata sebesar 2,22 m/s. Untuk mendapatkan berat pinang muda kering yang konstan, pengeringan ulangan 1 dan ulangan 2 membutuhkan waktu sampai 90 jam sedangkan ulangan 3 membutuhkan waktu pengeringan sampai 96 jam dengan ulangan 1 kadar air awal pinang muda adalah 74,4%. Perubahan mulai terjadi pada jam ke 24 sampai jam ke 90 dengan kadar air akhir pinang muda adalah 22,4% sedangkan pada ulangan 2 kadar air awal pinang muda adalah 74,0% selama 90 jam pengeringan menghasilkan kadar akhir sebesar 21,1%. Pengeringan pinang muda pada ulangan 3 kadar air awalnya sebesar 74,2% menghasilkan kadar air akhir sebesar 21,8% selama 96 jam pengeringan. Laju pengeringan rata-rata selama proses pengeringan sebesar 0,04 bk/jam. Peningkatan laju pengeringan terjadi pada jam ke 21. Study of Batel Nut (Areca catechu L) Drying Process Using Wood Biomass Fuel: A Case Study of PT. Areca Agro AcehAbstract. Drying young areca nut using wood biomass fuel can be done by covenant. Drying is done 3 times repetition at a temperature of 60oC, calculation of areca nut mass is measured every 3 hours for the first 24 hours, every 6 hours for the 2nd day until the mass of material is constant. Research parameters to determine the dry areca nut based on changes in material weight and moisture content include drying rate, air flow velocity, air humidity, temperature and material weight change.The results of research at PT. Areca Agro Aceh in the process of drying areca nut dry using wood biomass fuel produces an average air humidity of 56% with an average air flow velocity of 2.22 m / s. To get a constant weight of dry young areca nut, drying repetition 1 and repetition 2 takes up to 90 hours while repetition 3 requires drying time up to 96 hours with repetition 1 The initial water content of young areca nut is 74.4%. Changes began to occur at the 24th hour to the 90th hour with the final water content of young areca nut being 22.4% while in Repeat 2 the initial water content of the areca nut was 74.0% for 90 hours of drying resulting in a final content of 21.1%. Drying young areca nut on replicate 3, the initial water content of 74.2% produced a final water content of 21.8% for 96 hours of drying. The average drying rate during the drying process is 0.04 bk / hour. Increased drying rate occurs at 21 hours.

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