scholarly journals Effect of Straw Fiber Modification Methods on Compatibility between Straw Fibers and Cement-Based Materials

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Demin Jiang ◽  
Penghui An ◽  
Suping Cui ◽  
Shiguo Sun ◽  
Jingzong Zhang ◽  
...  
Keyword(s):  
Alkali Treatment ◽  
Setting Time ◽  
Treatment Method ◽  
Acrylic Emulsion ◽  
Fiber Modification ◽  
Structural Density ◽  
Fiber Treatment ◽  
Cement Based Materials ◽  
Modification Method ◽  
Alkali Modification

To improve the utilization of crop straws as a resource and the compatibility between straw fibers and cement-based materials, the hydration of modified straw fiber cement-based composite (SFCC) was studied. The structural characteristic of SFCC was investigated by FTIR, SEM, and XRD. The results show that the setting time of several modified straw fiber SFCC pastes was shorter than that of the unmodified straw fiber SFCC paste, and the best method of fiber modification to improve the setting time of the SFCC paste is Na2O·nSiO2 treatment. The recommended fiber modification method for improving the compatibility between straw fibers and cement-based materials is alkali modification, followed by pure acrylic emulsion modification and Na2O·nSiO2 modification. To improve the strength of SFCC, the straw fiber should be modified by alkali, followed by pure acrylic emulsion and Na2O·nSiO2 modification and the method of water modification is also recommended. The phase types and relative contents of crystalline hydration products mixed with the modified straw fiber SFCC are significantly higher than those of the unmodified fiber SFCC. The fiber treatment method that was most helpful to increase the structural density of hydrates of SFCC was alkali treatment and pure acrylic emulsion treatment, followed by Na2O·nSiO2 treatment.

scholarly journals Properties of Degraded Waste PET-Modified Styrene-Acrylic Emulsions for Cement Slurry Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jinxi Dou ◽  
Guijin Zhang ◽  
Sufang Li ◽  
Chengyu Tian ◽  
Cunlu Ji ◽  
...  
Keyword(s):  
Water Consumption ◽  
Water Retention ◽  
Retention Rate ◽  
Setting Time ◽  
Reduction Rate ◽  
Cement Slurry ◽  
Acrylic Emulsion ◽  
Water Reduction ◽  
Setting Times ◽  
Lower Permeability

The properties of a modified cement slurry based on degraded waste PET-modified styrene-acrylic emulsions are studied. The effects of the modified styrene-acrylic emulsion on water consumption, setting time, retarding effect, water retention, impermeability, and mechanical properties of the cement slurry are comprehensively studied. The results show that the modified styrene-acrylic emulsion has the following impacts on the cement slurry: it significantly reduces the water consumption required to reach a standard consistency, slows down the initial and final setting times, and greatly improves the water retention rate and water reduction rate. When the content of modified styrene-acrylic emulsion is 7.5%, the water reduction rate is 36% and the water retention rate is 97%. The solidified cement slurry with a modified styrene-acrylic emulsion content less than 7.5% has lower permeability and higher flexural strength than a common cement slurry. The compressive strength is reduced but can still reach required values. According to SEM observations, the modified styrene-acrylic emulsion can enhance the bonding strength between the cement particles, reduce the porosity of the structure, and improve the performance of cement-based composites.

Revaluation of Australian palm residues in polypropylene composites: Statistical influence of fiber treatment

2020 ◽  
pp. 002199832096053 ◽  
Author(s):  
Noelle C Zanini ◽  
Rennan FS Barbosa ◽  
Alana G de Souza ◽  
Derval S Rosa ◽  
Daniella R Mulinari
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Mechanical Performance ◽  
Alkali Treatment ◽  
Mechanical Analysis ◽  
Melt Mixing ◽  
Polypropylene Composites ◽  
Matrix Interactions ◽  
Fiber Treatment ◽  
Fiber Matrix

Australian palm residues are generated by palm heart industry in large quantities and are considered an underused material with a composition rich in lignocellulosic structures. This residue is generally utilized as briquettes for energy or sheep feed; however, few works investigate this residue as composite fillers. This work aimed to revalue Australian palm residues (PR) by preparing polypropylene composites through melt mixing, using different fiber contents (0, 5, 10, 20, and 30 wt%), and evaluate the statistical influence of fibers (residues) alkali treatment (MPR) in composites mechanical properties. PR and MPR were evaluated by FTIR, XRD, SEM, TGA, and composites were assessed using thermal and mechanical analysis, in which ANOVA statistical analysis was applied. The residues addition increased the mechanical properties and their treatment enhanced the stiffness of the composites compared to pristine PP. However, ANOVA demonstrated that at low residues contents, surface treatment does not increase fiber-matrix interactions effectively, then tensile properties were statistically similar to PP. Considering tensile properties, 20% MPR showed statistically distinct properties, with significative enhancements; no filler contents dependence was verified. Flexural properties were more sensitive to residue loading, and composites with 30% PR and MPR presented superior mechanical performance. This difference is associated with a higher sensitivity of tensile stress towards fiber-matrix interactions, which was improved with fiber treatment. Also, the residues content and treatment influenced the composites' thermal stability, with better results for PP-MPR. Results indicate that palm residue is an excellent filler for improving composites' thermal and mechanical properties, with a greener character.

scholarly journals Effect of Fiber Treatment on Stress-Strain Behavior of Kenaf Fibers Reinforced Thermoplastic Polyurethane Composites

2014 ◽  
Vol 575 ◽  
pp. 46-49 ◽  
Author(s):  
Y.A. El-Shekeil ◽  
S.M. Sapuan
Keyword(s):  
Natural Fiber ◽  
Alkali Treatment ◽  
Thermoplastic Polyurethane ◽  
Fiber Composites ◽  
Hibiscus Cannabinus ◽  
Alkali Concentration ◽  
Natural Fiber Composites ◽  
Stress Strain ◽  
Strain Behavior ◽  
Fiber Treatment

Natural fiber composites are getting much attention by researchers and industries. Natural fiber composites face the problem of incompatibility between fibers and polymers. Alkali treatment is the most common treatment for natural fiber composites. In this work, short “Kenaf (Hibiscus Cannabinus) Fiber” (KF) reinforced “Themoplastic ‎Polyurethane (TPU)” was prepared using Haake Polydrive R600 ‎internal mixer. After mixing, sheets for specimen cutting were prepared by compression molding. The aim of this work is to study the effect of alkali fiber treatment on stress-strain behavior of TPU/KF composites. Different alkali concentration was used, namely; 2, 4 and 6% NaOH. Tensile stress and strain were deteriorated with increase in NaOH concentration, while modulus increased slightly.

The Early-Age Drying Shrinkage of Cement-Based Materials with the same Workability after Temperature Compensation

2013 ◽  
Vol 405-408 ◽  
pp. 2604-2609
Author(s):  
Li Feng Zhang ◽  
Jun Ying Lai ◽  
Xiao Qian Qian ◽  
Chong Shen
Keyword(s):  
Temperature Compensation ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Concrete Specimen ◽  
Temperature Deformation ◽  
Control Group ◽  
Early Age ◽  
Peak Time ◽  
Initial Setting Time ◽  
Cement Based Materials

The early age drying shrinkage of cement-based materials with same the same workability staring from the initial setting time was studied. Superplasticizers (SP) were used to get the same workability. The drying shrinkage of paste was measured by clock gauge, and CABR-NES deformation instrument was used to measure the shrinkage of concrete. Temperature probes were buried into both paste and concrete specimen cores to measure the temperature curve, and temperature deformation was considered into the early shrinkage. Results show the addition of SP increases much more shrinkage than the control group, and polycarboxylate SP increases more shrinkage than naphthalene SP. The different temperature peak time of different mixtures show that the addition of SP changes the hydration process of cement, and the shrinkage of cement-based materials after temperature compensation is bigger than the measured value in the first 6 hours, but the gap is not big.

scholarly journals Evaluation of Self-Consolidating Concrete Robustness by Measuring Electrical Conductivity of Plastic Concrete

2018 ◽  
Author(s):  
Payam Vosoughi ◽  
Mahmoud Motahari Karein
Keyword(s):  
Electrical Conductivity ◽  
Setting Time ◽  
Test Methods ◽  
Test Method ◽  
Fresh Properties ◽  
Conventional Concrete ◽  
Self Consolidating Concrete ◽  
Plastic Concrete ◽  
Cement Based Materials ◽  
Long Time

This paper is aimed to review robustness of Self-Consolidating Concrete (SCC) in term of resistance against static segregation and bleeding. SCC is a highly fluid and non-segregating concrete able to spread through even dense reinforcement and homogenously fill formwork without using any external mechanical consolidation. Due to field requirements, SCC should be able to sustain its desired fresh properties over a relatively long time (about two or three hours) making it more susceptible to segregation than conventional concrete. Although there are a coupleof proposed test methods to evaluate SCC robustness, multi-electrodes electrical conductivity technique could be a reliable, non-destructive, inexpensive and simple test method to continuously monitor progress of hydration reactions (even indicating initial and final setting time) and stability (bleeding and both static and dynamic aggregate segregation) of plastic cement-based materials over the early-age period. In this paper, a brief review on fresh properties of SCC and staticaggregate segregation has been taken place. Then, different methods for measuring concrete conductivity have been investigated. Afterward, some studies on evaluation of stability of cement-based materials and SCC have been reviewed. Finally, based on the literature, some recommendations for future works are introduced.

Mechanical Properties of Rice-Husk Cement Composites Modified by SAE

2011 ◽  
Vol 71-78 ◽  
pp. 3470-3473 ◽  
Author(s):  
De Sheng Xiong ◽  
Fu Qin Han ◽  
Mo Chen
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Rice Husk ◽  
Mechanical Test ◽  
Alkali Treatment ◽  
Cement Composites ◽  
Acrylic Emulsion ◽  
Effective Additive ◽  
Scanning Electron ◽  
Material Standard

Cement-based composites were prepared from rice husk and styrene-acrylic emulsion (SAE) with semi-dry production process. The volume of SAE, the rice husk content and alkali treatment on the properties of the composites were studied. Particle-matrix bonding were observed with scanning electron microscope (SEM). The mechanical test of the rice-husk cement composites proved that SAE is an effective additive for reinforcing the composites, the mechanical properties improved significantly by alkali treatment and adding SAE. the properties can meet the requirement of the china building material standard(JC411—2007) when the content of SAE reached 3%.

scholarly journals Effect of Various Surface Treatments on the Performance of Jute Fibers Filled Natural Rubber (NR) Composites

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 369 ◽  
Author(s):  
Kumarjyoti Roy ◽  
Subhas Chandra Debnath ◽  
Lazaros Tzounis ◽  
Aphiwat Pongwisuthiruchte ◽  
Pranut Potiyaraj
Keyword(s):  
Natural Rubber ◽  
Alkali Treatment ◽  
Density Measurement ◽  
Tensile Modulus ◽  
Stress Transfer ◽  
Treatment Method ◽  
Surface Treatments ◽  
Silane Treatment ◽  
Jute Fibers ◽  
Surface Modified

In the present study, the suitability of various chemical treatments to improve the performance of jute fibers (JFs) filled natural rubber (NR) composites was explored. The surface of JFs was modified by three different surface treatments, namely, alkali treatment, combined alkali/stearic acid treatment and combined alkali/silane treatment. Surface modified JFs were characterized by X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). The reinforcing effect of untreated and surface treated JFs in NR composites was comparatively evaluated in terms of cure, mechanical, morphological and thermal properties. Combined alkali/silane treated JFs filled NR composite showed considerably higher torque difference, tensile modulus, hardness and tensile strength as compared to either untreated or other surface treated JFs filled NR systems. A crosslink density measurement suggested effective rubber-fibers interaction in combined alkali/silane treated JFs filled NR composite. Morphological analysis confirmed the improvement in the interfacial bonding between NR matrix and JFs due to combined alkali/silane treatment allowing an efficient “stress-transfer” mechanism. As a whole, combined alkali/silane treatment was found to be most efficient surface treatment method to develop strong interfacial adhesion between NR matrix and JFs.

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