Synergistic effects of curing conditions and magnesium oxide addition on the physico-mechanical properties and firing resistivity of Portland cement mortar

2018 ◽  
Vol 176 ◽  
pp. 676-689 ◽  
Author(s):  
H.A. Abdel-Gawwad ◽  
S.A. Abo El-Enein ◽  
Mohamed Heikal ◽  
S. Abd El-Aleem ◽  
A.A. Amer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Magnesium Oxide ◽  
Cement Mortar ◽  
Synergistic Effects ◽  
Curing Conditions ◽  
Oxide Addition

Effect of Nanometer Magnesium Oxide Addition on the Cast Microstructure of X80 Pipeline Steel

2013 ◽  
Vol 401-403 ◽  
pp. 610-613
Author(s):  
Jian Ming Wang ◽  
Yang Liu ◽  
Yan Liu ◽  
Qian He Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Magnesium Oxide ◽  
Pipeline Steel ◽  
Harsh Environment ◽  
Second Phase ◽  
X80 Pipeline Steel ◽  
Oxide Addition ◽  
Second Phase Particles ◽  
Cast Microstructure

The pipeline steel as an application in pipeline construction must have good comprehensive mechanical properties due to the harsh environment of the pipeline engineering. So this experiment takes the X80 pipeline steel as the research object, the thermal stability second phase particles which would not be dissolved or aggregated at high temperature will be expected by means of adding nanomagnesium oxide into the steel with the method of carrier dispersion addition. The effect of nanometer magnesium oxide addition on the cast microstructure of X80 pipeline steel was analysed. The results show that the cast microstructure is consist of the ferrite and a small amount bainite. And the bainite is distributed at the boundary of the ferrite grains. When adding 0.02 wt% nanometer magnesium oxides, the number of bainite increases significantly in the cast microstructure, which is mostly distributed at the boundary of the ferrite grains.

EFFECT OF STYRENE-BUTADIENE COPOLYMER (SBR) LATEX ON MECHANICAL AND TRANSPORT PROPERTIES OF PORTLAND CEMENT MORTAR

2020 ◽  
Vol 15 (4) ◽  
pp. 185-197
Author(s):  
Daniel Hatungimana ◽  
Şemsi Yazici ◽  
Şevket Orhan ◽  
Ali Mardani-Aghabaglou
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Detrimental Effect ◽  
Cement Mortar ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Replacement Level ◽  
Cement Production ◽  
Cement Ratio ◽  
Styrene Butadiene

ABSTRACT Portland cement is extensively used as a binder in concrete production. However, with Portland cement production, 5% of the natural resources used in this production are consumed, constituting 5–7% of the total CO2 emission. In order to mitigate the environmental problems associated with cement production, styrene-butadiene rubber latex was used as cement replacement up to 20%. In this study, compressive strength, flexural strength, unit weight, water absorption, open porosity, water sorptivity and the chloride ion permeability of Portland cement mortar mixtures modified by styrene-butadiene rubber (SBR) polymeric latex were investigated. For this purpose, the sand/cement ratio and the water/cement ratio were kept constant as 3/1 and 0.5, respectively. In addition to the control mixture containing no polymer, 1, 2, 3, 5, 10 and 20 wt.% of cement was replaced with SBR. In this way, seven mortar mixtures were prepared. Mixed curing (wet cure and dry cure) method was applied to the mortar specimens. Results showed that up to a 5% replacement level, it is possible to improve the mechanical properties of cement mortars with SBR latex addition. However, at a 10% and 20% replacement level, SBR had a significant detrimental effect on the mechanical properties of polymer modified mortars. However, the transport properties decreased with the incorporation rate of SBR latex and the detrimental effect of SBR replacement was more pronounced in 20% SBR mortar mixtures.

Simulation of Mechanical Properties of Light-Burned Magnesium Oxide-Containing Concrete for Historical Dam Temperatures

2017 ◽  
Vol 744 ◽  
pp. 45-54
Author(s):  
Yong Min Yang ◽  
Zhao Heng Li ◽  
Tong Sheng Zhang ◽  
Qi Jun Yu
Keyword(s):  
Mechanical Properties ◽  
Body Temperature ◽  
Magnesium Oxide ◽  
Constant Temperature ◽  
Variable Temperature ◽  
Curing Temperature ◽  
Engineering Practice ◽  
Curing Conditions ◽  
Mgo Concrete ◽  
Curing Regime

Previous studies showed that curing regime has a significant influence on mechanical properties of light-burned magnesium oxide (MgO) concrete. However, research has been limited mostly to constant-temperature studies, whereas dams manufactured from concrete exist in variable-temperature environments. In order to achieve material performance parameters that agree more closely with engineering practice, the development of mechanical properties of light-burned MgO concrete curing at constant temperature and simulated dam body temperature was studied. The compressive strength, elastic modulus and ultimate tensile strain of light-burned MgO concrete increased with the increase of curing temperature, MgO content and curing age. These constant-temperature properties were similar to those under simulated dam body temperature curing conditions. A comparison of experimental results of simulated dam body temperature curing and constant temperature curing showed that a thermostatic curing system was suitable for calculating the laws of mechanics development for dam concrete.

Review on the Effect of Bottom Ash in Performance of Portland Cement Mortar

2015 ◽  
Vol 815 ◽  
pp. 164-169
Author(s):  
Ng Hooi Jun ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Husin ◽  
Soo Jin Tan ◽  
Mohd Firdaus Omar
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Mechanical Performance ◽  
Cement Mortar ◽  
Bottom Ash ◽  
The Other ◽  
Other Hand

Utilization and suitability of bottom ash in Portland cement have been increasing significantly in recent year. Bottom ash has substantial effects on mechanical properties with different composition of replacement in mixture of bottom ash and Portland cement. Bottom ash was used to determine the feasibility of the substitution as recycling product from industry depending on the percentage of the bottom ash. On the other hand, bottom ash offers a better solution for maintaining materials characteristic of Portland cement mortar and also provide beneficial mechanical performance. The result of using bottom ash in Portland cement mortar showed that it could make better the mechanical properties and hence disposed bottom ash wastes safely in technical, economic and environmental methods.

Hybrid effects of carbon fibers on mechanical properties of Portland cement mortar

2015 ◽  
Vol 65 ◽  
pp. 1222-1228 ◽  
Author(s):  
Xiang Shu ◽  
Ryan K. Graham ◽  
Baoshan Huang ◽  
Edwin G. Burdette
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Carbon Fibers ◽  
Cement Mortar

Mechanical Properties of Recycled Binder/Micro-Filler Cement-Based Material

2014 ◽  
Vol 1054 ◽  
pp. 234-237 ◽  
Author(s):  
Martin Lidmila ◽  
Jaroslav Topič ◽  
Tomáš Plachy ◽  
Zdeněk Prošek ◽  
Václav Nežerka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Efficiency ◽  
Flexural Strength ◽  
Portland Cement ◽  
Production Process ◽  
Mechanical Performance ◽  
Concrete Structures ◽  
Recycled Concrete ◽  
Strength Parameters ◽  
Curing Conditions

The presented study addresses the mechanical performance of micro-filler cement-based material produced from recycled concrete sleepers. Such material can be considered both, as a binder and filler at the same time. The main advantage of such material is the energy efficiency of the production process, since there is no demand for increased temperature. Compression and flexural strength parameters of such material are compared with those of a composite based on commonly used Portland cement. Moreover, the influence of curing conditions on the strength parameters was investigated as well. The results indicate that the recycled sleepers can be used in the form of micro-filler cement-based to replace a certain portion of cement in concrete and reduce cost of concrete structures.

scholarly journals Evaluation of Carbon Nanotube Incorporation in Cementitious Composite Materials

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1504 ◽  
Author(s):  
Ana Catarina Jorge Evangelista ◽  
Jorge Fernandes de Morais ◽  
Vivian Tam ◽  
Mahfooz Soomro ◽  
Leandro Torres Di Gregorio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Portland Cement ◽  
New Technologies ◽  
Cement Mortar ◽  
Construction Material ◽  
Optimal Dosage ◽  
Potential Contribution ◽  
Sem Images ◽  
Split Tensile Strength

Over the last decades, new materials with outstanding performance have been introduced in the construction industry. Considering these new technologies, it is worth mentioning that nanotechnology has revolutionized various areas of engineering. In the area of civil engineering and construction, cement is used for various purposes and the search to improve its performance has been receiving growing interest within the scientific community. The objective of this research was to evaluate the behavior of cement mortar produced by the addition of multi-walled carbon nanotubes (MWCNTs) in different concentrations by comparing their physical and mechanical properties with the properties of the nanotube-free composite. Motivated by the lack of consensus in the literature concerning to the optimal dosage of CNTs in cementitious matrices, three different carbon nanotube ratios, 0.20, 0.40 and 0.60 wt % Portland cement, were investigated with the aim of evaluating the mechanical properties. Destructive tests were carried out to determine the compressive strength, flexural strength and split tensile strength. Additionally, a non-destructive test was performed to determine the dynamic elastic modulus and density. Scanning electron microscopy (SEM) images showed the interaction between the MWCNTs and the hydration products of Portland cement mortar. The results indicated the potential contribution of 0.40 wt % cement CNTs to the enhancement of the mechanical properties of the cement composite as a promising construction material.

scholarly journals Carbon Storage in Portland Cement Mortar: Influences of Hydration Stage, Carbonation Time and Aggregate Characteristics

2021 ◽  
Vol 3 (3) ◽  
pp. 563-580
Author(s):  
Luqman Kolawole Abidoye ◽  
Diganta B. Das
Keyword(s):  
Particle Size ◽  
Portland Cement ◽  
Carbon Storage ◽  
Cement Mortar ◽  
Fine Sand ◽  
Coarse Sand ◽  
Curing Time ◽  
Curing Conditions ◽  
Surface Areas ◽  
Ettringite Formation

This study elucidates the effects of the particle size, carbonation time, curing time and pressure on the efficiency of carbon storage in Portland cement mortar. Using pressure chamber experiments, our findings show how carbonation efficiency increases with a decrease in the particle size. Approximately 6.4% and 8.2% (w/w) carbonations were achieved in the coarse-sand and fine-sand based mortar samples, respectively. For the hydration/curing time of 7 h, up to 12% carbonation was achieved. This reduced to 8.2% at 40 h curing period. On the pressure effect, for comparable curing conditions, 2 bar at 7 h carbonation time gives 1.4% yield, and 8.2% at 5 bar. Furthermore, analysing the effect of the carbonation time, under comparable conditions, shows that 4 h of carbonation time gives up to 8.2% yield while 64 h of carbonation gives up to 18.5%. It can be reliably inferred that, under similar conditions, carbonation efficiency increases with lower-sized particles or higher-surface areas, increases with carbonation time and higher pressure but decreases with hydration/curing time. Microstructural analyses with X-ray diffraction (XRD) and scanning electron microscopy (SEM) further show the visual disappearance of calcium-silicate-hydrate (C-S-H) together with the inhibition of ettringite formation by the presence of CO2 and CaCO3 formation during carbonation.

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