Effect of chemical admixtures on borogypsum containing cement mortar

2017 ◽  
Vol 16 (4) ◽  
pp. 227-239 ◽  
Author(s):  
Kubra Kunt ◽  
Fatma Dur ◽  
Meral Yildirim ◽  
Emek Moroydor Derun
Keyword(s):  
Cement Mortar ◽  
Chemical Admixtures

scholarly journals Preparation of Electric- and Magnetic-Activated Water and Its Influence on the Workability and Mechanical Properties of Cement Mortar

2021 ◽  
Vol 13 (8) ◽  
pp. 4546
Author(s):  
Kaiyue Zhao ◽  
Peng Zhang ◽  
Bing Wang ◽  
Yupeng Tian ◽  
Shanbin Xue ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Paste ◽  
Cement Mortar ◽  
Environmental Issues ◽  
Chemical Admixtures ◽  
Untreated Water ◽  
Alternating Voltage

Cement-based materials prepared with activated water induced by a magnetic field or electric field represent a possible solution to environmental issues caused by the worldwide utilization of chemical admixtures. In this contribution, electric- and magnetic-activated water have been produced. The workability and mechanical properties of cement mortar prepared with this activated water have been investigated. The results indicate that the pH and absorbance (Abs) values of the water varied as the electric and magnetic field changed, and their values increased significantly, exhibiting improved activity compared with that of the untreated water. In addition, activated water still retains activity within 30 min of the resting time. The fluidity of the cement paste prepared with electric-activated water was significantly larger than that of the untreated paste. However, the level of improvement differed with the worst performance resulting from cement paste prepared with alternating voltage activated water. In terms of mechanical properties, both compressive strength and flexural strength obtained its maximum values at 280 mT with two processing cycles. The compressive strength increased 26% as the curing time increased from 7 days to 28 days and flexural strength increased by 31%. In addition, through the introduction of magnetic-activated water into cement mortar, the mechanical strength can be maintained without losing its workability when the amount of cement is reduced.

scholarly journals Effectiveness of Thermal Stimulation of Superplasticizers on Fresh Properties of Cement Mortar

2021 ◽  
Author(s):  
Mizuki Takigawa ◽  
Hiroshi Nemoto ◽  
Shin-ichiro Hashimoto ◽  
Shigeyuki Date
Keyword(s):  
Cement Mortar ◽  
Plastic Viscosity ◽  
Thermal Stimulation ◽  
Polycarboxylic Acid ◽  
Construction Sites ◽  
Shear Tests ◽  
Polymer Molecules ◽  
Chemical Admixtures ◽  
Environmental Temperatures ◽  
Stimulation Of

AbstractPolycarboxylic acid-based superplasticizers are used in various types of concrete work. Wide variations in environmental temperatures are known to affect how well chemical admixtures perform as superplasticizers, influencing the properties of the concrete. However, little has been reported on changes in performance caused by thermal variations. Previous studies have reported that heating superplasticizers change the polymer structure, improving and sustaining cement particles' dispersibility. Moreover, the improved fluidity from thermal stimulation is not temporary. The effect has been observed to remain for about seven days, with the residual characteristics differing depending on the superplasticizers used. Therefore this study evaluates mortar stiffness when using thermally stimulated superplasticizers and evaluates how the stimulation affects construction performance using measures such as the flow and rheological properties (plastic viscosity) of fresh mortar, vane shear tests, blade viscometer tests, and mortar vibration box tests. Mortar's fluidity was found to improve by about 25% when using thermally stimulated additives, with plastic viscosity dropping by up to 45% and the stress likely to be needed for pumping also being reduced by about 16%. Filling speed was also found to increase by about 26%. Thus, thermal stimulation improves mortar and concrete construction performance, and it may be possible in the future to carry out the construction with fewer workers utilizing this technology’s benefits. The study indicates a need for further investigation of how thermal stimulation affects polymer molecules’ adsorption efficiency with cement to elucidate the mechanism at full scale and propose ways to adopt thermal stimulation at actual construction sites.

Studying effects of chemical admixtures on the workability retention of zeolitic Portland cement mortar

2014 ◽  
Vol 72 ◽  
pp. 262-269 ◽  
Author(s):  
Hessam AzariJafari ◽  
Ali Kazemian ◽  
Babak Ahmadi ◽  
Javad Berenjian ◽  
Mohammad Shekarchi
Keyword(s):  
Portland Cement ◽  
Cement Mortar ◽  
Chemical Admixtures

scholarly journals Effects of selected chemical admixtures on physical and mechanical properties of cement mortar

2020 ◽  
Vol 30 (3) ◽  
pp. 305-310
Author(s):  
SS Bethe ◽  
MN Haque ◽  
MR Islam
Keyword(s):  
Mechanical Properties ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Chemical Admixtures ◽  
Super Plasticizer ◽  
The Difference

This study was aimed to determination of appropriate dosage of selected chemical admixtures to reduce water cement ratio for mortar mix also to determine its effects on physical and mechanical properties of cement mortar. Amount of water used in concrete is very important for the physical and mechanical properties. Less amount of water increase the strength but reduce the workability. Water retarding admixture can reduce the water cement ratio with desired workability. In this experiment plasticizer (master pel 707) and super plasticizer (master polyheed 8632) was used. The used dosages of admixture were 0.5%, 1% and 1.5% according to cement weight. The test was done at 3 days, 7 days, 28 days and 91 days. 2.76″ cube mold was used for the work. The experiment was done to find the difference between with and without admixture used in mortar. Water used reduced with add of plasticizer and super plasticizer. In the experiment the workability of normal mortar and admixture used mortar remain same. The compressive strength is high for 1.5% super plasticizer used sample. So 1.5% super plasticizer is recommended for high strength. Progressive Agriculture 30 (3): 305-310, 2019

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.

An Examination on Hybrid Structures Renovated from the Old Railway Steel Bridges with Polymer Cement Mortar

2016 ◽  
Vol 106 (1) ◽  
pp. 1014-1019
Author(s):  
Nozomu TANIGUCHI ◽  
Yusuke SUGINO ◽  
Fujikazu OHKUBO ◽  
Weiwei LIN ◽  
Shinya SATAKE ◽  
...  
Keyword(s):  
Cement Mortar ◽  
Steel Bridges ◽  
Hybrid Structures
Sign in / Sign up

Export Citation Format

Share Document