Evaluate the durability and effect of water absorption of recycled aggregate used in pavement

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

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Strength and Water Absorption of Sustainable Concrete Produced with Recycled Basaltic Concrete Aggregates and Powder

Sustainability ◽

10.3390/su13116277 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6277

Author(s):

Ibrahim Sharaky ◽

Usama Issa ◽

Mamdooh Alwetaishi ◽

Ahmed Abdelhafiz ◽

Amal Shamseldin ◽

...

Keyword(s):

Water Absorption ◽

Edge Length ◽

Recycled Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Partial Substitution ◽

Small Reduction ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Sustainable Concrete

In this study, the recycled concrete aggregates and powder (RCA and RCP) prepared from basaltic concrete waste were used to replace the natural aggregate (NA) and cement, respectively. The NA (coarse and fine) was replaced by the recycled aggregates with five percentages (0%, 20%, 40%, 60% and 80%). Consequently, the cement was replaced by the RCP with four percentages (0%, 5%, 10% and 20%). Cubes with 100 mm edge length were prepared for all tests. The compressive and tensile strengths (fcu and ftu) and water absorption (WA) were investigated for all mixes at different ages. Partial substitution of NA with recycled aggregate reduced the compressive strength with different percentages depending on the type and source of recycled aggregate. After 28 days, the maximum reduction in fcu value was 9.8% and 9.4% for mixtures with coarse RCA and fine RCA (FRCA), respectively. After 56 days, the mixes with 40% FRCA reached almost the same fcu value as the control mix (M0, 99.5%). Consequently, the compressive strengths of the mixes with 10% RCA at 28 and 56 days were 99.3 and 95.2%, respectively, compared to those of M0. The mixes integrated FRCA and RCP showed higher tensile strengths than the M0 at 56 d with a very small reduction at 28 d (max = 3.4%). Moreover, the fcu and ftu values increased for the late test ages, while the WA decreased.

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Use of Bioproducts Derived from Mixed Microbial Cultures Grown with Crude Glycerol to Protect Recycled Concrete Surfaces

Materials ◽

10.3390/ma14082057 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2057

Author(s):

Lorena Serrano-González ◽

Daniel Merino-Maldonado ◽

Manuel Ignacio Guerra-Romero ◽

Julia María Morán-del Pozo ◽

Paulo Costa Lemos ◽

...

Keyword(s):

Water Absorption ◽

Crude Glycerol ◽

Protective Layer ◽

Recycled Concrete ◽

Recycled Aggregate ◽

World Population ◽

Management Problem ◽

Waste Glycerol ◽

Microbial Cultures ◽

Mixed Microbial Cultures

The large increase in the world population has resulted in a very large amount of construction waste, as well as a large amount of waste glycerol from transesterification reactions of acyl glycerides from oils and fats, in particular from the production of biodiesel. Only a limited percentage of these two residues are recycled, which generates a large management problem worldwide. For that reason, in this study, we used crude glycerol as a carbon source to cultivate polyhydroxyalkanoates (PHA)-producing mixed microbial cultures (MMC). Two bioproducts derived from these cultures were applied on the surface of concrete with recycled aggregate to create a protective layer. To evaluate the effect of the treatments, tests of water absorption by capillarity and under low pressure with Karsten tubes were performed. Furthermore, SEM-EDS analysis showed the physical barrier caused by biotreatments that produced a reduction on capillarity water absorption of up to 20% and improved the impermeability of recycled concrete against the penetration of water under pressure up to 2.7 times relative to the reference. Therefore, this bioproduct shown to be a promising treatment to protect against penetration of water to concrete surfaces increasing its durability and useful life.

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The effect of water absorption and the role of fines on the yield stress of dense fly ash slurries

Cement and Concrete Research ◽

10.1016/s0008-8846(98)00250-6 ◽

1999 ◽

Vol 29 (5) ◽

pp. 765-767 ◽

Cited By ~ 9

Author(s):

R.S. Iyer ◽

B. Stanmore

Keyword(s):

Fly Ash ◽

Water Absorption ◽

Yield Stress ◽

Effect Of Water

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Effect of water absorption on physical properties of high nitrile barrier polymers

Polymer Engineering & Science ◽

10.1002/pen.760260605 ◽

1986 ◽

Vol 26 (6) ◽

pp. 405-409 ◽

Cited By ~ 5

Author(s):

S. A. Jabarin ◽

E. A. Lofgren

Keyword(s):

Physical Properties ◽

Water Absorption ◽

Effect Of Water ◽

Barrier Polymers

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Effects of Imposed Damage on the Capillary Water Absorption of Recycled Aggregate Concrete

Advances in Materials Science and Engineering ◽

10.1155/2018/2890931 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Qi Gao ◽

Zhiming Ma ◽

Jianzhuang Xiao ◽

Fuan Li

Keyword(s):

Absorption Coefficient ◽

Water Absorption ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Capillary Absorption ◽

Capillary Water ◽

Aggregate Concrete ◽

Capillary Water Absorption ◽

Freeze Thaw ◽

Loading Level

Capillary water absorption of concrete is closely related to its pore structure, permeability, and durability. This paper intensively investigates the effects of imposed damage, including freeze-thaw damage and loading damage, on the capillary water absorption of recycled aggregate concrete (RAC). Freeze-thaw cycle test, loading test, and the experiment of capillary water absorption were carried out, respectively. The results demonstrate that the addition of recycled coarse aggregate (RCA) results in the increase in the capillary absorption behavior of RAC without imposed damage, and there exists a linear correlation between the behaviors of capillary water absorption and chloride penetration of RAC. The imposed freeze-thaw damage or load damage of RAC boosts with the increase of RCA replacement percentages after suffering the same freeze-thaw cycles or loading level. The imposed freeze-thaw damage and load damage further lead to the increase in the capillary water absorption of RAC, and the capillary absorption coefficient of RAC increases linearly with the increased RCA replacement percentages, after suffering the same freeze-thaw cycles or loading level. Furthermore, capillary absorption coefficient increases linearly with the growth of imposed freeze-thaw damage or load damage degree, which can be used to estimate the capillary absorption behavior of RAC exposed to the extreme environment.

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