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.

scholarly journals Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Bone Substitutes ◽  
Bacterial Strains ◽  
Setting Times ◽  
Biological Studies

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

A Study of Downhole Drillable Pulsing Cementing Device with Low Frequency Self-Excited Hydraulic Oscillation and its Field Application

2012 ◽  
Vol 450-451 ◽  
pp. 1536-1539
Author(s):  
Cui Ping Nie ◽  
Deng Sheng Ye
Keyword(s):  
Setting Time ◽  
Low Frequency ◽  
Field Application ◽  
Displacement Efficiency ◽  
Cement Slurry ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Gas Well ◽  
Hydraulic Oscillation ◽  
Injection Technology

Abstract: Usually we pay more attention on how to improve gas well cementing quality in engineering design and field operations, and there are so many studies on cement agents but few researches on cement slurry injection technology. The field practice proved that conventional cementing technology can not ensure the cementing quality especially in gas well and some abnormal pressure wells. Most of the study is concentrated on cement agents and some cementing aspects such as wellbore condition, casing centralization etc. All the factors analysis on cementing quality has pointed out that a combination of good agents and suitable measurements can improve cementing quality effectively. The essential factor in cementing is to enhance the displacement efficiency, but normal hole condition and casing centralization are the fundamental for cementing only. Pulsing cementing is the technology that it can improve the displacement efficiency especially in reservoir well interval, also it can shorten the period from initial to ultimate setting time for cement slurry or improve thickening characteristics, and then to inhibit the potential gas or water channeling. Based on systematically research, aiming at improving in 7″ liner cementing, where there are multi gas reservoirs in long interval in SiChuan special gas field, well was completed with upper 7″ liner and down lower 5″ liner, poor cementing bonding before this time. So we stressed on the study of a downhole low frequency self-excited hydraulic oscillation pulsing cementing drillable device and its application, its successful field utilization proved that it is an innovative tool, and it can improve cementing quality obviously.

scholarly journals Influence of Organic Esters on Portland Cement Hydration and Hardening

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Duan-le Li ◽  
Da-peng Zheng ◽  
Dong-min Wang ◽  
Ji-hui Zhao ◽  
Cheng Du ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Cement Hydration ◽  
Setting Time ◽  
Exothermic Peak ◽  
Hardened Cement ◽  
Test Results ◽  
Trimethyl Phosphate ◽  
Cement Slurry ◽  
Hydration Degree ◽  
Dimethyl Oxalate

This paper investigated the effect of organic compounds with ester groups on the hydration and hardening of cement. The effects of five kinds of organic compounds with ester groups (ethyl acetate, dimethyl oxalate, glyceryl triacetate, trimethyl phosphate, and triethanolamine borate) on hydration heat, hydration degree, setting time, mechanical properties, microstructure, and pore structure of hardened cement slurry were studied. The test results showed that esters can make the end time of cement hydration induction longer and delay the occurrence of the second exothermic peak. Also, the effect of five kinds of esters on the hydration and hardening of cement was basically followed by TG> TB> DMO> EAC> TMP. In terms of molecular structure, for organic compounds containing only ester groups, the higher the number of ester groups, the greater the effect on the hydration of cement. The introduction of other functional groups (such as phosphate or borate) will influence the effect of the esters.

Behaviour of Calcium Alkali Orthophosphate Cements under Simulated Implantation Conditions

2008 ◽  
Vol 396-398 ◽  
pp. 213-216 ◽  
Author(s):  
Daniela Jörn ◽  
Renate Gildenhaar ◽  
Georg Berger ◽  
Michael Stiller ◽  
Christine Knabe
Keyword(s):  
Compressive Strength ◽  
Simulated Body Fluid ◽  
Clinical Application ◽  
Body Fluid ◽  
Setting Time ◽  
Great Decrease ◽  
Final Setting Time ◽  
Laboratory Conditions ◽  
Setting Times

The setting behaviour, the compressive strength and the porosity of four calcium alkali orthophosphate cements were examined under laboratory conditions (dry) and under conditions similar to those during clinical application (37°C, contact with body fluid). The results showed an increase of the setting times when specimens were covered with simulated body fluid. Especially, the final setting time (FHZ) was significantly higher for three of the four cements. Furthermore, when specimens were stored in SBF for 16h, an extensive decrease of the compressive strength was noted. The porosity was more than twice as high after 16h in SBF and this may be the cause for the great decrease of the compressive strength.

scholarly journals Development of Interlocking Concrete Blocks with Added Sugarcane Residues

Fibers ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 61 ◽  
Author(s):  
Bruno Ribeiro ◽  
Tadaaki Uchiyama ◽  
Jun Tomiyama ◽  
Takashi Yamamoto ◽  
Yosuke Yamashiki
Keyword(s):  
Flexural Strength ◽  
Water Retention ◽  
Retention Rate ◽  
High Water ◽  
Urban Heat Islands ◽  
Water Evaporation ◽  
Heat Islands ◽  
Concrete Blocks ◽  
Urban Heat ◽  
Bagasse Fiber

The use of sugarcane residues in mortar and concrete is believed to contribute to a reduction of costs and environmental problems, such as the reduction of mining of natural aggregates and incorrect disposal of the sugarcane residues. Bagasse fiber has a high water retention rate and thus may be considered as a countermeasure for urban heat islands. Because of these properties, bagasse fiber and bagasse sand were added into the preparation of the interlocking concrete blocks. An investigation of the flexural strength and the contribution of the sugarcane residues against an urban heat island was made. The results showed that, by adding 2.0% of bagasse fiber and 5.0% of bagasse sand in concrete, the flexural strength and the water retention content increased in comparison to the control composite. Moreover, the surface temperature and the water evaporation rate of the blocks were smaller in comparison to the control composite.

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 Comparative Study of Soil Grouting with Cement Slurry and Cement-Sodium Silicate Slurry

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mingting Zhu ◽  
Qingsong Zhang ◽  
Xiao Zhang ◽  
Bing Hui
Keyword(s):  
Sodium Silicate ◽  
Large Scale ◽  
Setting Time ◽  
Initial Pressure ◽  
Cement Slurry ◽  
Viscosity Change ◽  
Grouting Pressure ◽  
Curtain Grouting ◽  
Grouting Reinforcement

Cement slurry and cement-sodium silicate slurry are most widely applied for soil grouting reinforcement project. The viscosity change of cement slurry is negligible during grouting period and presumed to be time independent, while the viscosity of cement-sodium silicate slurry increases with time quickly and is presumed to be time dependent. Due to the significant rheological differences between them, the grouting quality and the increasing characteristics of grouting parameters may be different. Those are main factors for grouting design. In this paper, a large-scale 3D grouting simulation device was developed to simulate the surrounding curtain grouting for a tunnel. Two series of surrounding curtain grouting experiments under different initial pressures of 100 kPa, 150 kPa, and 200 kPa were performed. The overload test on the tunnel was performed to evaluate the grouting quality of all surrounding curtain grouting experiments. The results show that the increasing trend of grouting pressure for cement-sodium silicate is similar to its viscosity; the setting time of cement-sodium silicate slurry obtained from the laboratory test is less than that in the practical grouting environment where grout slurry solidifies in soil; the grouting quality of cement-sodium silicate slurry is better than cement slurry, and the grouting quality decreases with initial pressure.

The Aging Properties of Bamboo-Poplar Composite Oriented Strand Board with Different Hybrid Ratios

2014 ◽  
Vol 599-601 ◽  
pp. 140-143 ◽  
Author(s):  
Xiang Fei Fu ◽  
Cheng Yong ◽  
Ming Jie Guan
Keyword(s):  
Water Absorption ◽  
Modulus Of Elasticity ◽  
Oriented Strand Board ◽  
Retention Rate ◽  
Reduction Rate ◽  
Detailed Comparison ◽  
Perpendicular Direction ◽  
Internal Bonding ◽  
Thickness Swelling ◽  
Aging Properties

In this paper, the bamboo-poplar composite oriented strand board (OSB) with different hybrid ratios were aged under the standard of ASTM D1037 to evaluate its weathering performances. The thickness swelling (TS), water absorption, modulus of rapture in perpendicular direction (MOR⊥), modulus of elasticity in perpendicular direction (MOE⊥) and internal bonding (IB) of specimens were tested. The results showed that the reduction rate of TS ranged from 21% to 69%, which increased with the poplar ratio increasing; the growth multiple of 24h water absorption of bamboo-poplar composite OSB were at the similar level, the values of which were much smaller than that of the pure bamboo or poplar OSB; the maximum and minimum retention rate of MOR⊥ and MOE⊥ belonged to pure bamboo and poplar OSB respectively, retention rate of MOR⊥ of the bamboo-poplar composite OSB rose with the increment of poplar ratio, while retention rate of MOE⊥ and IB of bamboo-poplar composite OSB were similar and the hybrid ratio 2.5:7.5(bamboo: poplar) obtained the maximum IB retention rate of 16%. Through detailed comparison, the bamboo-poplar composite OSB with the hybrid ratio 2.5:7.5 performed the best after aging.

Preparation of Calcium Phosphate Cement Utilizing Dicalcium Phosphate Dihydrate and Calcium Carbonate

2014 ◽  
Vol 608 ◽  
pp. 280-286
Author(s):  
Nudthakarn Kosachan ◽  
Angkhana Jaroenworaluck ◽  
Sirithan Jiemsirilers ◽  
Supatra Jinawath ◽  
Ron Stevens
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Cement Pastes ◽  
Setting Times ◽  
Phosphate Dihydrate

Calcium phosphate cement has been widely used as a bone substitute because of its chemical similarity to natural bone. In this study, calcium phosphate cement was prepared using dicalcium phosphate dihydrate (CaHPO4.2H2O) and calcium carbonate (CaCO3) as starting raw materials. The cement pastes were mixed and the chemistry adjusted with two different aqueous solutions of sodium hydroxide (NaOH) and disodium hydrogen phosphate (Na2HPO4). Concentrations of the solution were varied in the range 0.5 to 5.0 mol/L with the ratio of solid/liquid = 2 g/ml. The cement paste was then poured into a silicone mold having a diameter of 10 mm and a height 15 mm. Setting times for the cement were measured using a Vicat apparatus. XRD, FT-IR, and SEM techniques were used to characterize properties and microstructure of the cement. From the experimental results, it is clear that different concentrations of Na2HPO4 and NaOH have affected the setting times of the cement. The relationship between concentration of NaOH and Na2HPO4 and setting time, including final properties of the cement, is discussed.

The High Performance Concrete Curing Agent Based on Polyacrylic Emulsion with Hydroxyl Monomer HPMA

2014 ◽  
Vol 584-586 ◽  
pp. 1126-1129 ◽  
Author(s):  
Rui Wang ◽  
Lei Li ◽  
Hong Song Wang ◽  
Wen Bin Wang ◽  
Wei Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Water Retention ◽  
High Performance Concrete ◽  
Retention Rate ◽  
Structural Parameters ◽  
Positive Influence ◽  
Hydroxyl Groups ◽  
Curing Agent ◽  
Agent Based ◽  
Chemical Structures

The influence of the chemical structures of styrene/butyl acrylate/hydroxyl propyl methacrylate emulsion on some properties of ordinary Portland cement concretes has been investigated as concrete curing agent. The structural parameters that are varied included the fractions of HPMA and the polymer structure of the shell-core. The result of the study showed that the hydroxyl monomer HPMA played an important role on the improvement of water retention and the optimal proportion is about 5 wt% of the polymer. In addition, the shell-core structure of the emulsion with HPMA located in shell polymer can further enhance the water-retention rate. Besides, the emulsion with hydroxyl groups could smooth the surface of the concrete, inhibit the carbonation and had positive influence on the compressive strength.

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