scholarly journals Analysis of the Effect of Nano-SiO2 and Waterproofing Agent on the Water Transportation Process in Mortar Using NMR

2020 ◽  
Vol 10 (21) ◽  
pp. 7867
Author(s):  
Tao Meng ◽  
Huadong Wei ◽  
Kanjun Ying ◽  
Menghua Wang
Keyword(s):  
Water Absorption ◽  
Moisture Diffusion ◽  
Test Results ◽  
Capillary Water ◽  
Process Data ◽  
Capillary Water Absorption ◽  
Nano Sio2 ◽  
Water Transportation ◽  
Cement Based Materials ◽  
Transportation Process

Moisture diffusion in cement-based materials significantly impacts its durability. In this study, we analyzed the effect of adding a waterproofing agent and nano-SiO2 (NS) on the water transportation process in mortar using capillary water absorption tests and nuclear magnetic resonance (NMR) technology. The results indicate that the combined action of the waterproofing agent and nano-SiO2 drastically reduce the capillary water absorption coefficient and have a more significant impact than only adding the waterproofing agent. The moisture diffusion in different sections of the mortar during the water absorption process is obtained from the NMR test results and two function models. Comparative studies indicate that the NMR test results have good correlation with the capillary water absorption test results and provide accurate process data. The NMR analysis results offer a new analytical method to characterize the porosity of cement-based materials by continuously monitoring small-pitch sections.

scholarly journals The effect of silanes as integral hydrophobic admixture on the physical properties of cement based materials

2021 ◽  
Vol 2069 (1) ◽  
pp. 012045
Author(s):  
K Grabowska ◽  
A Wieczorek ◽  
D Bednarska ◽  
M Koniorczyk
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Physical Properties ◽  
Water Absorption ◽  
Cement Mortar ◽  
Organosilicon Compounds ◽  
Capillary Water ◽  
Main Ingredient ◽  
Capillary Water Absorption ◽  
Cement Based Materials

Abstract The paper explores the possibility of using organosilicon compounds (e.g., poly(dimethylsiloxane) and triethoxyoctylsilane) in commercial admixtures as internal hydrophobization agents for porous cement-based materials. The study involved the cement mortar with five different hydrophobic admixtures. Four of them is based on triethoxyoctylsilane, but with various concentration of the main ingredient, and one of them on poly(dimethylsiloxane). Mechanical properties, capillary water absorption, as well as microstructure were investigated. The organosilicon admixtures efficiently decrease the capillary water absorption even by 81% decreasing mechanical strength of cement mortar at the same time even by 55%. Only one admixture, based on poly(dimethylsiloxane) caused significant changes in microstructure of cement mortar.

scholarly journals Influence of a New Type of Graphene Oxide/Silane Composite Emulsion on the Permeability Resistance of Damaged Concrete

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Xu Chen ◽  
Youlai Zhang ◽  
Shaochun Li ◽  
Yongjuan Geng ◽  
Dongshuai Hou
Keyword(s):  
Graphene Oxide ◽  
Water Absorption ◽  
Penetration Depth ◽  
Protective Mechanism ◽  
Test Results ◽  
X Ray Diffraction ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
X Ray ◽  
New Type

Through penetration depth tests, capillary water absorption tests under different abrasion depths, and capillary water absorption tests of a cement mortar test block with crack damage, a self-prepared, novel, graphene oxide/silane composite emulsion used for the effect of wear or cracking damage was studied. The waterproof performance of concrete and the protective mechanism of a composite emulsion was verified by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The test results showed that the penetration depth of the composite emulsion reached depths greater than 9 mm, which yielded a good waterproof effect; when the concrete was cracked or worn, the composite emulsion still had a stable waterproof performance. It was found that the composite emulsion could form a hydrophobic layer with a certain thickness inside the cement-based material, which explains why the composite emulsion had a good waterproof effect.

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

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
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.

scholarly journals The Influence of 30 Years Outdoor Weathering on the Durability of Hydrophobic Agents Applied on Obernkirchener Sandstones

Buildings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
Jeanette Orlowsky ◽  
Franziska Braun ◽  
Melanie Groh
Keyword(s):  
Water Absorption ◽  
Water Uptake ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
Absorption Determination ◽  
Colour Changes ◽  
Uptake Velocity ◽  
Outdoor Weathering

The durability of eleven different water repellents applied on one sandstone type was studied after a long-term weathering at seven different locations in Germany. By measuring colour changes, it could be shown that the formation of black crusts, the deposition of particles and biogenic growth caused a gradual darkening as well as significant changes in total colour over time. Additionally, the water absorption behaviour was investigated with two different methods: applying a low pressure using the pipe method and capillary water absorption measurements from a wet underlay. Afterwards, the test results were analysed with four different evaluation methods: calculation of the protection degree from pipe method and capillary water absorption, determination of the velocity of water uptake during capillary water absorption and calculation of the damaged depth of the stone surface using single-sided NMR technique. The growing damaged depth leads to an increase of the water uptake velocity and to a decrease of the protection degree of the applied hydrophobing agents. Three protective agents based on isobutyltrimethoxysilane showed already after two years of outdoor weathering a clear loss of performance, which significantly increased after 30 years of exposure.

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