The Flowability and Adsorption of Low Sulfate Cement with Superplasticizers

2013 ◽  
Vol 477-478 ◽  
pp. 904-907
Author(s):  
Ming Zhe An ◽  
Song Han
Keyword(s):  
Charge Density ◽  
Cement Paste ◽  
Water Demand ◽  
Cement Slurry ◽  
Sulfate Content ◽  
Standard Dosage ◽  
Slump Test ◽  
Adsorbed Amount ◽  
Lower Charge

The compatibility of low sulfate cement with naphthalene (NS) and polycarboxylate (PCE) type superplasticizers was discussed. The flowability of slurry and the adsorption of superplasticizers (SP) were investigated by mini slump test and TOC. The results show that severe compatibility degeneration is caused by low sulfate content in cement slurry. The water demand of slurry, the standard dosage and adsorbed amount of SPs were dramatically raised. In the cement slurry with low sulfate content, polycarboxylate type superplasticizers presents better performance than naphthalene type. The PCE with lower charge density presents better robustness. It is recommended in the preparation of concrete to avoid the incompatibility problems caused by lack of sulfate in cement paste.

scholarly journals Water demand of amorphous nano silica and its impact on the workability of cement paste

2012 ◽  
Vol 42 (2) ◽  
pp. 344-357 ◽  
Author(s):  
G. Quercia ◽  
G. Hüsken ◽  
H.J.H. Brouwers
Keyword(s):  
Cement Paste ◽  
Water Demand ◽  
Nano Silica

scholarly journals Effect of ultrafine natural steatite powder, super plasticizer and VMA on the fresh and hardened properties of self-compacting cement paste and mortar

2021 ◽  
Author(s):  
S. Christopher Gnanaraj ◽  
Ramesh Babu Chokkalingam ◽  
G. Lizia Thankam ◽  
S.K.M. Pothinathan
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Water Demand ◽  
Construction Material ◽  
Setting Time ◽  
Mineral Admixture ◽  
Self Healing ◽  
Chemical Admixtures ◽  
Hardened Properties ◽  
Viscosity Modifying Admixture

AbstractFor the past few decades innovation in construction material has grown a lot. This leads to special concrete such as self-compacting concrete, geopolymer concrete, self-healing concrete, etc. To prepare a special concrete apart from regular concreting material some sort of special materials was also needed, like mineral and chemical admixtures. Hence it is necessary to study the effect of these admixtures in cement paste and mortar before studying the same in concrete. Hence an attempt is made to study the effect of mineral and chemical admixtures in the fresh and hardened properties of cement paste and mortar. For this study ultrafine natural steatite powder is taken as mineral admixture and polycarboxylic based superplasticizer and glenium stream 2 were taken as chemical admixtures. Ultrafine natural steatite powder was used as additive to cement in various percentages like 0%, 5%, 10%, 15%, 20% and 25%. Superplasticizer and viscosity modifying admixture were taken as 1.5% and 0.5%, respectively. Then various combinations were worked out. To study the fresh property of cement paste consistency, initial setting time and miniature slump cone test were done based on the results yield stress of cement paste also calculated empirically. To study the hardened property compression test on cement mortar was done. Based on the test results it is clear that the addition of ultrafine natural steatite powder increases the water demand hence reduces the workability. On the other hand, it increases the compressive strength up to a certain limit. Adding superplasticizer increases the workability and reduces the water demand and viscosity modifying admixture reduces the bleeding and segregation effects hence increases the compressive strength.

Carbon Dioxide Corrosion and Corrosion Prevention of Oil Well Cement Paste Matrix in Deep Wells

2014 ◽  
Vol 692 ◽  
pp. 433-438 ◽  
Author(s):  
Jing Fu Zhang ◽  
Jin Long Yang ◽  
Kai Liu ◽  
Bo Wang ◽  
Rui Xue Hou
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Cement Paste ◽  
Oil Wells ◽  
Oil Well ◽  
Cement Slurry ◽  
Corrosion Prevention ◽  
Oil Well Cement ◽  
Oil Well Cement Paste ◽  
Well Cement

Carbon dioxide CO2could corrode the oil well cement paste matrix under agreeable moisture and pressure condition in deep oil wells, which could decrease the compressive strength and damage the annular seal reliability of cement paste matrix. The problem of oil well cement paste matrix corrosion by CO2was researched in the paper for obtain the feasible corrosion prevention technical measures. The microstructure and compressive strength of corroded cement paste matrix were examined by scanning electron microscopeSEMand strength test instrument etc. under different corrosion conditions. The mechanism and effect law of corrosion on oil well cement paste matrix by CO2were analyzed. And the suitable method to protect CO2corrosion in deep oil wells was explored. The results show that the corrosion mechanism of cement paste matrix by CO2was that the wetting phase CO2could generate chemical reaction with original hydration products produced from cement hydration, which CaCO3were developed and the original composition and microstructure of cement paste matrix were destroyed. The compressive strength of corrosion cement paste matrix always was lower than that of un-corrosion cement paste matrix. The compressive strength of corrosion cement paste matrix decreased with increase of curing temperature and differential pressure. The corroded degree of cement paste matrix was intimately related with the compositions of cement slurry. Developing and design anti-corrosive cement slurry should base on effectively improving the compact degree and original strength of cement paste matrix. The compounding additive R designed in the paper could effectively improve the anti-corrosive ability of cement slurry.

scholarly journals Effect of Acid Activation-Hydrophilic-Modified Sepiolite on Comprehensive Properties of Oil-Well Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yihang Zhang ◽  
Miao He ◽  
Mingbiao Xu ◽  
Peng Xu
Keyword(s):  
Cement Paste ◽  
Oil Well ◽  
Acid Activation ◽  
Cement Slurry ◽  
Comprehensive Properties ◽  
Oil Well Cement ◽  
Before And After ◽  
Sepiolite Fiber ◽  
Well Cement ◽  
Agent Treatment

In this paper, sepiolite was treated by acid activation, coupling agent treatment, and sulfonation modification. The purpose of this study was to explore the changes in the fluidity and mechanical properties of sepiolite cement slurry before and after modification. Therefore, the comprehensive properties of unmodified sepiolite fiber (HPS) and acid activation-coupling agent treatment-sulfonated sepiolite fiber (S-O-H-HPS) in oil-well cement slurry were evaluated. FT-IR and microscopic mechanism of cement paste fracture surface before and after sepiolite modification were analyzed. The results showed that HPS can effectively improve the toughness of cement paste, but when the content of HPS was more than 1%, the fluidity of cement paste deteriorated sharply and the compressive strength decreased gradually. The addition of S-O-H-HPS can significantly improve the fluidity and stability of HPS slurry. Without affecting the compressive strength, it can effectively improve the flexural strength and impact strength and reduce the elastic modulus of cement paste. The mechanism analysis showed that S-O-H-HPS can not only form network structure in cement paste but also improve the toughness of cement paste by forming a bridge. This also explains why the strength of S-O-H-HPS cement paste does not decrease significantly with the increase of S-O-H-HPS.

The Performance Evaluation of New Low Temperature early Strength Agent ZL-1

2013 ◽  
Vol 470 ◽  
pp. 842-846
Author(s):  
Ji Gang Wang ◽  
An Qi Tong ◽  
Zhen Zhong Fan ◽  
Qing Wang Liu
Keyword(s):  
Performance Evaluation ◽  
Low Temperature ◽  
Silica Fume ◽  
Cement Paste ◽  
Cement Slurry ◽  
Hydration Rate ◽  
Anionic Polymers ◽  
Temperature Conditions ◽  
Chlorine Ions ◽  
Early Strength

Low temperature early strength cement slurry is a slurry in order to meet the well cementation in low-temperature conditions. Daqing weather is characterized by the silica fume, solid alcohols, amines and anionic polymers prepared a certain proportion, got a new low temperature early strength agent, It can greatly accelerate the hydration rate of cement and promote the formation of the cement paste early strength; and no chlorine ions, able to overcome the problem caused by traditional chlorine early strength agent casing corrosion.

Violation of Kohler's Rule in the Magnetoresistance near the Lower Charge-Density-Wave Instability in NbSe3

2005 ◽  
Vol 74 (6) ◽  
pp. 1787-1791 ◽  
Author(s):  
Syuma Yasuzuka ◽  
Kazuhiko Yamaya ◽  
Yoshitoshi Okajima ◽  
Satoshi Tanda ◽  
Nao Takeshita ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Instability ◽  
Lower Charge

Pressure effect on large magnetoresistance in the lower charge-density-wave transition ofNbSe3

1999 ◽  
Vol 60 (7) ◽  
pp. 4406-4409 ◽  
Author(s):  
Syuma Yasuzuka ◽  
Yoshitoshi Okajima ◽  
Satoshi Tanda ◽  
Kazuhiko Yamaya ◽  
Nao Takeshita ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Pressure Effect ◽  
Density Wave ◽  
Lower Charge

scholarly journals Experimental Study of Reinforcing Broken Gangues by Colloid Cement Slurry

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xin Lyu ◽  
Ke Yang ◽  
Qiang Fu ◽  
Zhen Wei ◽  
Shuai Liu
Keyword(s):  
Failure Mode ◽  
Cement Paste ◽  
Failure Modes ◽  
Axial Strain ◽  
Optimal Choice ◽  
Strengthening Effect ◽  
Reinforcement Effect ◽  
Cement Slurry ◽  
Load Bearing ◽  
Failure Patterns

Studies on jet grouting materials mainly focus on the aggregates in cement or the environment where they are maintained and rarely deal with the cohesiveness, reinforcement load-bearing characteristics, and surface spalling. In this study, cement slurries with different colloid contents were prepared to explore the characteristics and reinforcement effect of broken gangues. These were then subjected to mechanical testing to measure the strength and axial strain performance, and the failure modes and failure patterns were discussed. The results indicated that the colloid component has a significant strengthening effect on the early strength of the samples. As the age increased, the sample axial strain and elastic modulus of the colloid cement paste increased as the colloid component provides viscoelasticity when it resists deformation. The sample strength of cement paste decreases after the addition of broken gangue while the strength of class E samples increases significantly during each age. The cement paste sample showed penetrating splitting failure, the colloidal component effectively controlled the peeling of sample surface, and the failure mode after adding gangue was relatively complicated. The instability modes of the samples are divided into dispersed load-bearing instability and cumulative load-bearing instability, and the content of colloid components affects the failure mode of the samples. A colloid component proportion of 23.33% is the optimal choice, which has an obvious reinforcement effect on the broken gangue.

scholarly journals Milling of peat-wood fly ash: Effect on water demand of mortar and rheology of cement paste

2018 ◽  
Vol 180 ◽  
pp. 143-153 ◽  
Author(s):  
Jouni Rissanen ◽  
Katja Ohenoja ◽  
Paivo Kinnunen ◽  
Marcello Romagnoli ◽  
Mirja Illikainen
Keyword(s):  
Fly Ash ◽  
Cement Paste ◽  
Water Demand
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