scholarly journals The Failure Mechanisms of Precast Geopolymer after Water Immersion

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5299
Author(s):  
Shunfeng Wang ◽  
Long Yu ◽  
Linglin Xu ◽  
Kai Wu ◽  
Zhenghong Yang
Keyword(s):  
Compressive Strength ◽  
Water Resistance ◽  
Water Immersion ◽  
Failure Mechanisms ◽  
Steel Slag ◽  
Total Porosity ◽  
Structure And Morphology ◽  
Concentration Of Ions ◽  
Leaching Solution ◽  
Pressing Technology

Precast geopolymers with lower water/binder (0.14), which mainly consists of alkali solution, fly ash (FA) and steel slag (SS), were manufactured through molding pressing technology. The failure mechanisms of precast geopolymers after water immersion were studied by testing the loss of compressive strength, the pH of the leaching solution, the concentration of ions (Na+, Ca2+, Si4+ and Al3+), the evolution of phases, pore structure and morphology, and further discussion of the regulation evolution was performed. The results show that the harmful pores (>50 nm) of geopolymers progressively decrease from 70% to 50% after 28 days of water immersion when the content of steel slag increases from 0 to 80 wt.%. Compressive strength of geopolymers sharply reduces in the first 3 days and then increases during the water immersion process, but the phase composition varies slightly. Furthermore, increasing the content of steel slag could decrease the total porosity and further prevent the water resistance.

Utilization of Phosphogypsum as Raw Material for Manufacturing of Non-Fired Load-Bearing Wall Bricks

2011 ◽  
Vol 374-377 ◽  
pp. 787-791
Author(s):  
Lin Yang ◽  
Yun Yan ◽  
Zhi Hua Hu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Frost Resistance ◽  
Water Resistance ◽  
Steel Slag ◽  
Raw Material ◽  
Equal Weight ◽  
Sand Content ◽  
Load Bearing

Non-fired load-bearing wall brick was prepared utilizing non-treated original waste PG as raw material in the laboratory. When the amount of PG and cement is 65% and 10% (by weight) in the brick mixture, respectively, the compressive strength of bricks is still over 23MPa and the flexural strength comes up to 4MPa. Besides, the bricks hold excellent water-resistance and frost-resistance. Effects of steel slag or/and fly ash content on performance of bricks and effects of the change of sand content on water-resistance and frost-resistance are discussed. Results indicate that the compressive strength, flexural strength and soft coefficient are higher when blended mineral additive with various amounts of steel slag and fly ash. The frost-resistance goes up with the increase of the steel slag content, the water-resistance and frost-resistance goes down when the sand content decreases from 15% to 10%, no matter the 5% sand was replaced by fly ash or steel slag as equal weight. Microstructure of brick was investigated by XRD and SEM. Strength of brick results from a large amount of AFt (3CaO•Al2O3•3 CaSO4•32H2O) and C-S-H (calcium silicate hydrate) presented in the matrix which may be viewed as the biggest strength contributors bonding the gypsum and quartz together to a compact matrix.

scholarly journals Waterborne Polyurea Coatings Filled with Sulfonated Graphene Improved Anti-Corrosion Performance

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 251
Author(s):  
Jijia Zhang ◽  
Jihu Wang ◽  
Shaoguo Wen ◽  
Siwei Li ◽  
Yabo Chen ◽  
...  
Keyword(s):  
Composite Coating ◽  
Water Resistance ◽  
Electrochemical Impedance ◽  
Water Immersion ◽  
Doping Content ◽  
Corrosion Performance ◽  
Water Contact ◽  
Sulfonated Graphene ◽  
Long Time ◽  
Scanning Electron

In this paper, an environmentally friendly waterborne polyurea (WPUA) emulsion and its corresponding coating were prepared, which was characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). To improve the performance of the coating, we doped sulfonated graphene (SG) into WPUA to prepare composite coating (SG/WPUA). SG can be uniformly dispersed in WPUA emulsion and is stable for a long time (28 days) without delamination. The water resistance of the composite coating with 0.3 wt.% SG nanofiller was improved; the water contact angle (WCA) result was SG/WPUA (89°) > WPUA (48.5°), and water absorption result was SG/WPUA (2.90%) < WPUA (9.98%). After water immersion treatment, SEM observation revealed that the SG/WPUA film only generated enlarged microcracks (100 nm) instead of holes (150–400 nm, WPUA film). Polarization curves and electrochemical impedance spectroscopy (EIS) tests show that SG nanosheets with low doping content (0.3 wt.%) are more conducive to the corrosion resistance of WPUA coatings, and the model was established to explain the mechanism.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

scholarly journals A Novel Approach to Fabricate Foam Ceramics from Steel Slag

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yu Zheng ◽  
Xudong Luo ◽  
Jinlong Yang ◽  
Wenlong Huo ◽  
Chi Kang
Keyword(s):  
Compressive Strength ◽  
Ph Value ◽  
Steel Slag ◽  
Raw Material ◽  
Solid Loading ◽  
Insulation Material ◽  
Ceramic Foams ◽  
Novel Approach ◽  
The Stability ◽  
First Time

A novel approach is used for fabricating steel slag foam ceramics based on the particle-stabilized foaming method. In this work, steel slag was used as the raw material and propyl gallate (PG) was used as the surface modifier. For the first time, steel slag ceramic foams were successfully fabricated based on particle-stabilized foams. The results show that the stability of the ceramic foams was closely related to the pH value and PG concentration. The porosity and compressive strength could be controlled by changing the solid loading of steel slag and sintering temperature. The porosity of steel slag foam ceramics ranged from 85.6% to 62.53%, and the compressive strength was from 1.74 MPa to 10.42 MPa. The thermal conductivity of steel slag foam ceramics was only 0.067 W (m·K)−1, which shows that it could be used as a thermal insulation material.

Influences of Emulsion on Water Resistance of Vitrified Micro Bubbles Thermal Insulation Material

2013 ◽  
Vol 662 ◽  
pp. 433-436
Author(s):  
Jiang Zhu ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
Stearic Acid ◽  
Thermal Insulation ◽  
Water Resistance ◽  
Insulation Material ◽  
Molding Process ◽  
Thermal Insulation Material ◽  
Improve Water Resistance ◽  
Softening Coefficient

Vitrified micro bubbles thermal insulation material was made of vitrified micro bubbles, cement, fly ash, gypsum and sodium silicate, by molding process. VAE emulsion and stearic acid-polyvinyl alcohol emulsion were added to improve water resistance of the material. Mixed with 10% VAE emulsion and 5% stearic acid-polyvinyl alcohol emulsion, properties of the material are followed as: flexural strength 0.64MPa, compressive strength 1.35MPa, softening coefficient 0.71 and 2h volumetric water absorption 6.9%.

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

Water resistance of heat-treated welded Iroko, ash, tulip, and ayous wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9584-9595
Author(s):  
Mustafa Zor
Keyword(s):  
Shear Strength ◽  
Water Resistance ◽  
Chemical Constituents ◽  
Water Immersion ◽  
Control Sample ◽  
Strength Loss ◽  
Control Group ◽  
Line Density ◽  
Heat Treated ◽  
Structural Applications

The friction welding method has been an effective criterion in determining the mechanical performance of wood joints in wood industry applications compared to traditional methods. Although it is used in structural applications, joints from linear vibration are quite sensitive to water. In this study, the water resistance of the heat-treated woods, iroko (Chlorophora excelsa), ash (Fraxinus excelsior L.), tulip wood (Liriodendron tulipifera) and ayous (Triplochiton scleroxylon), were investigated by friction linear welding. The weld line density profiles were examined. The resistance of heat-treated welded wood joints to water remarkably decreased compared to the control sample, depending on water immersion time. The highest shear strength loss was found in tulip wood (60% to 65%) and the lowest shear strength loss was found in ash wood (3%) for the heat-treated group and in Iroko wood (17%) for the control. The heat-treated samples increased in density with welding but had a slightly lower density than the control group. According to the TGA results, it was found that the thermal degradation of untreated welded woods was lower than that of heat-treated welded woods. This difference could be due to the chemical constituents of hardwood and tropical wood. X-ray computed tomography (CT-scanning) is feasible and usable for welding line density change.

Quaternary blended cement mortars containing wood ash, glass and slag powders

2021 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Marwa Saadi Mhmood
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Glass Powder ◽  
Steel Slag ◽  
Wood Ash ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Slag Powder ◽  
Steel Slag Powder

AbstractA quaternary supplementary cementitious materials as partial replacement of ordinary Portland cement decreases CO2 emission. This paper has investigated the properties of mortars made from different quaternary blends of wood ash, steel slag powder and glass powder with ordinary Portland cement at different replacement levels of 0, 24, 25, and 30% by weight of the binder. The blended mortar mixtures tested for flow, compressive strength and density. The results showed that the flow of mortars is decreased with the combined use of steel slag powder, glass powder, and wood ash compared with control mix. Compressive strength reduced with the combination of steel slag powder, glass powder and wood ash but this reduction effects is acceptable especially at 24% replacement contain super-plasticizer compared with the ecological benefit.

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