scholarly journals Retarding effect of grinding dust and its influence on the physical-mechanical and rheological properties of cementitious matrices

2019 ◽  
Vol 12 (3) ◽  
pp. 486-508
Author(s):  
R. D. MARIANO ◽  
J. S. ANDRADE NETO ◽  
M. R. MORELLI ◽  
D. V. RIBEIRO
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Setting Time ◽  
Squeeze Flow ◽  
Retarding Effect ◽  
Finishing Process ◽  
Flow Table ◽  
Hardened State

Abstract The present study evaluated the feasibility of the use of grinding dust (GD), a waste generated in the clutch disc finishing process, as a retardant additive in cementitious matrices. For this, the waste was added in contents of 5%, 10% and 15%, relative to the cement weight, and the setting time was determined by the Vicat method. In addition, the influence of this material on rheology (flow table, squeeze-flow and rotational rheometry) and on the physical-mechanical properties of the hardened matrices was analyzed. The results indicated an increase in setting time and a reduction in the fluidity of the mortars as a function of the addition of GD and the best results for the hardened state properties were verified for the cementitious matrices containing a 5% addition. Therefore, it was observed that GD is effective in retarding the setting time, presenting great potential for use in civil construction, without impairing its properties.

Effect of Metakaolin on Geopolymer Industry

2019 ◽  
pp. 49-70
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Reaction Mechanisms ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Experimental Studies ◽  
Acid Attack ◽  
Repair Materials ◽  
Hardened State

This chapter discusses the effects of metakaolin (MK) on geopolymer mortar and concrete industries. The research topics of MK-based geopolymer cover reaction mechanisms and kinetics. This chapter aims at augmenting knowledge about enhancing mechanical properties of geopolymer mortars/concrete using MK. Specifically, this chapter presents literature studies as well as current experimental studies which delineate the effect of MK on fresh and hardened-state properties of geopolymer mortars (GPMs). Properties and characteristics of metakaolin are explained followed by properties of fresh MK mortars. Properties of hardened MK concrete and durability aspects of MK mortars are explained. Applications of MK-based geopolymers and metakaolin-based geopolymers as repair materials are also included in this chapter. The results of using MK-based GPMs revealed improved workability, enhanced setting time, increased density, higher compressive strength, flexural strength, and resistance against acid attack than conventional ordinary portland cement mortar/concrete.

scholarly journals Modification of cement systems by carbon nanotubes

2019 ◽  
Author(s):  
Skripkiunas Gintautas
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Titanium Dioxide ◽  
Composite Materials ◽  
Construction Industry ◽  
Setting Time ◽  
Oxide Nanoparticles ◽  
Nano Silica ◽  
Hardened State ◽  
Aluminium Oxide Nanoparticles

The nanoparticles and nanostructures such as nano silica, nano metakaolin, titanium dioxide and aluminium oxide nanoparticles, graphite nanomaterials, carbon nanotubes are used for modification of composite materials in construction industry. The considerable attention of researchers is focused on the investigation of cement systems modified by carbon nanotubes (CNT). The present research describes the generalized data about modification of cement systems by CNT suspension in fresh and hardened state. The influence of carbon nanotubes on setting time of cement paste, rheological and mechanical properties of nanomodified cement systems are demonstrated in the present research.

Effects of Temperature and Chemical Admixtures on the Properties of Rock-Based Geopolymers Designed for Zonal Isolation and Well Abandonment

2021 ◽  
Author(s):  
Fawzi Chamssine ◽  
Mahmoud Khalifeh ◽  
Elsayed Eid ◽  
Mona Wetrhus Minde ◽  
Arild Saasen
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Elevated Temperatures ◽  
Setting Time ◽  
Strength Development ◽  
Fluid Loss ◽  
Rotational Viscometer ◽  
Well Abandonment ◽  
Uniaxial Compressive Strength Test ◽  
The Impact

Abstract In this paper, the impact of temperature and admixture-based salts on the mechanical and rheological properties, and composition of geopolymers was studied. Neat geopolymer and Class-G cement, manufactured by Dyckerhoff, were used as reference samples at elevated temperatures. To enhance the additive properties of the geopolymer slurry, a combination of K and Zn was examined with a variety of K:Zn ratio ranging from ∼0.15 to ∼0.25. The workability of samples was tested by using an atmospheric consistometer, while other rheological properties were examined by running fluid loss test, and rotational viscometer test. The sample with the best workability was cured for 1, 3, and 7 days at bottomhole static temperatures of 70 and 80°C and pressure of 140 MPa where the mechanical properties were examined by ultrasonic cement analyzer and uniaxial compressive strength test. X-ray diffraction was used to analyze the composition of samples at different curing times and temperatures. The obtained results showed that the salt derivative admixtures have a significant impact on the oligomerization and polycondensation phases, where it distinctively elongated the setting time, enhanced strength, and strength development. On the other hand, the temperature effect was clearly observed by reducing rheological properties, while maintaining similar mechanical properties.

Influence of Superplasticizers on the Properties of Lightweight Mortar Plaster Made with Recycled Polymers

2015 ◽  
Vol 1129 ◽  
pp. 546-553 ◽  
Author(s):  
J. Garabito ◽  
Lourdes Alameda ◽  
Jesús Gadea ◽  
Sara Gutiérrez-González
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Rheological Properties ◽  
Ceramic Materials ◽  
Interface Zone ◽  
Hardened State ◽  
Polyamide Powder ◽  
Lightweight Mortar ◽  
Scanning Electron

The advantageous influence of two different polycarboxylate and melamine superplasticizers is studied in relation to the properties of blended mortar plaster made with recycled polymers (polyamide powder and polyurethane foam). The characteristics of the test specimens are defined and tested in both a fresh and a hardened state. The influence of the additives on the microstructure of the lightweight mortar plaster is defined through an analysis of the compatibility of the interface zone of the materials using Fast Scanning Electron Microscopy (FSEM).Our results show that the addition of additives influences the properties of the mortar plaster, enhances its mechanical properties, and increases its adherence with ceramic materials. These results confirm that superplasticizers (depending on the type and dosage) enhance both the properties of the mortar plasters produced with recycled polymers and the rheological properties of the mortars that include polyamide waste.

scholarly journals Effects of Chemical Admixtures on the Working and Mechanical Properties of Ordinary Dry-Mixed Mortar

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Shu-Chun Zhou ◽  
Heng-Lin Lv ◽  
Ning Li ◽  
Jie Zhang
Keyword(s):  
Mechanical Properties ◽  
Water Retention ◽  
Cement Mortar ◽  
Setting Time ◽  
Methyl Cellulose ◽  
Cellulose Ether ◽  
Hydroxypropyl Methyl Cellulose ◽  
Chemical Admixtures ◽  
Retarding Effect ◽  
Mixed Mortar

The effects of hydroxypropyl methyl cellulose ether, starch ether, bentonite, and redispersion emulsoid powder on the working and mechanical properties of fresh dry-mixed mortar were studied. The results show that hydroxypropyl methyl cellulose ether has the greatest impact on the consistency and water retention of ordinary dry-mixed mortar and that redispersion emulsoid powder reduces the water action and starch ether has essentially no effect on water retention. It also shows that the time of mortar condensation when mixed with hydroxypropyl methyl cellulose ether is the longest, followed by redispersion emulsoid powder and bentonite. Starch ether can slightly, but not obviously, extend the setting time of cement mortar. Hydroxypropyl methyl cellulose ether has the greatest impact on the mechanical properties of ordinary dry-mixed mortar, followed by redispersion emulsoid powder, starch ether, and bentonite. As the water retention increases, the setting time of the mortar also increases. The use of water as a thickening material has a retarding effect on the mortar, increases the water-retention rate, and increases the retarding effect. Moreover, increasing the content of the chemical admixtures decreases the strength of cement mortar.

Geopolymer Grout Material

2016 ◽  
Vol 841 ◽  
pp. 40-47 ◽  
Author(s):  
Retno Trimurtiningrum ◽  
Januarti Jaya Ekaputri
Keyword(s):  
Raw Materials ◽  
Setting Time ◽  
Test Methods ◽  
Alkali Concentration ◽  
Final Setting Time ◽  
Flow Table ◽  
Alternative Material ◽  
Hardened State ◽  
Class F Fly Ash ◽  
Geopolymer Material

This paper presents an experimental study of geopolymer material as an alternative material for grouting. The samples were class F Fly ash as raw materials, activated with 6M, 8M, and 10 M concentration of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Superplasticizer from naphtelenesulphonatedand polycarboxylic ether hyper plasticizer in the range of 0-3% were added to improve its workability. Some test methods are conducted to the samples to know the fresh and hardened-state properties of geopolymer mixture.The experimental results showed that the longest initial and final setting time were about 13 minutes and 20 minutes, respectively at the lowest alkali concentration mixtures. The flowability of geopolymer paste and geopolymer mortar were 154% with flow table test. However, mixtures with the highest alkali concentration showed highest compressive strength of 104,5 MPa and 71 MPa for pasteand mortar respectively.

scholarly journals Effects of Surfactants on the Properties of Mortar Containing Styrene/Methacrylate Superplasticizer

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
El-Sayed Negim ◽  
Latipa Kozhamzharova ◽  
Jamal Khatib ◽  
Lyazzat Bekbayeva ◽  
Craig Williams
Keyword(s):  
Mechanical Properties ◽  
Glycidyl Methacrylate ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Monomethyl Ether ◽  
Butyl Methacrylate ◽  
Glycol Monomethyl Ether ◽  
Flow Table ◽  
Polyoxyethylene Glycol ◽  
Polymer Latex

The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA.

scholarly journals Influence of polypropylene microfibre (PPMF) dispersion procedure on fresh and hardened rendering mortar properties

2020 ◽  
Vol 20 (2) ◽  
pp. 7-23 ◽  
Author(s):  
Sérgio Roberto Andrade Dantas ◽  
Ramoel Serafini ◽  
Roberto Cesar de Oliveira Romano ◽  
Fúlvio Vittorino ◽  
Kai Loh
Keyword(s):  
Drying Shrinkage ◽  
Air Entrainment ◽  
Squeeze Flow ◽  
Fresh Properties ◽  
Capillary Water ◽  
Immersion Method ◽  
Flow Table ◽  
Hardened State ◽  
Dimensional Variation ◽  
Reference Specimens

Abstract This study was carried out to evaluate the influence of a polypropylene microfibre (PPMF) dispersion procedure on fresh and hardened state properties of rendering mortars. Specimens prepared with two different PPMF dispersion procedures were evaluated comparatively with reference specimens prepared without adding PPMF. Changes in the fresh properties were monitored using flow table, squeeze flow, and air-entrainment tests. The hardened state was characterized by capillary water absorption, air-permeability, dynamic elastic modulus (E), tensile strength according to the Brazilian test, and porosity by the Archimedes immersion method. Results show that the fresh mortar properties were not affected by dispersion procedure and all hardened mortar properties were statistically similar, except for the dimensional variation of the specimens. The study also shows that adding polypropylene microfibres in a dispersed form was more effective in terms of controlling total drying shrinkage than directly adding fibres to the cementitious matrix (as recommended by the manufacturer) or the reference mortar.

Study of Rheological Properties of Modified Concrete Mixtures at Vibration

2019 ◽  
Vol 968 ◽  
pp. 96-106
Author(s):  
Oleksandr Pshinko ◽  
Olena Hromova ◽  
Dmytro Rudenko
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Physical Nature ◽  
Concrete Mixture ◽  
Practical Significance ◽  
Vibration Displacement ◽  
Concrete Mixtures ◽  
Variable Quantity ◽  
Vibration Compaction ◽  
Mechanism Of Interaction

Study of rheological properties of concrete mixtures based on modified cement systems in order to determine process parameters. Methodology. To study structural-mechanical properties of modified concrete mixtures of different consistency at their horizontal vibrating displacement an oscillatory viscometer was designed. Results. The optimization of the process of vibration displacement of concrete mixtures with the specification of parameters of vibration impacts taking into account structural-mechanical properties of the mixture is performed. It has been established that the viscosity of the modified cement system of the concrete mixture is a variable quantity, which depends on the parameters of the vibration impacts. Scientific novelty. The mechanism of interaction of the modified concrete mixture with the form and the table vibrator during its vibration compaction is determined. On the basis of this, a model of concrete laying process control is proposed, that allows to predict the ability to form a dense concrete structure. Practical significance. Disclosed physical nature of the process of vibrating displacement of modified concrete mixtures using the principles of physical-chemical mechanics of concrete allows reasonably choose the best options for vibration impacts.

scholarly journals Effects of Steel Fiber Percentage and Aspect Ratios on Fresh and Harden Properties of Ultra-High Performance Fiber

2021 ◽  
Vol 2 (3) ◽  
pp. 501-515
Author(s):  
Rajib Kumar Biswas ◽  
Farabi Bin Ahmed ◽  
Md. Ehsanul Haque ◽  
Afra Anam Provasha ◽  
Zahid Hasan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
High Performance ◽  
Steel Fiber ◽  
Setting Time ◽  
Fiber Reinforced Concrete ◽  
Future Research ◽  
Manufacturing Cost ◽  
Aspect Ratios ◽  
High Performance Fiber

Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.

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