scholarly journals The Mechanism of Compressive Strength Development for Cement Pastes Cured at High Temperature and the Possibility of Additives as to Improve Long-Term Strength

2010 ◽  
Vol 59 (10) ◽  
pp. 743-750
Author(s):  
Hiroaki MORI ◽  
Ryuichiro KUGA ◽  
Haruka TAKAHASHI ◽  
Masami UZAWA
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Strength Development ◽  
Term Strength ◽  
Cement Pastes ◽  
Compressive Strength Development

scholarly journals Evaluation of the long-term compressive strength development of the sewage sludge ash/metakaolin-based geopolymer

2021 ◽  
Vol 71 (343) ◽  
pp. e254
Author(s):  
D. Istuque ◽  
L. Soriano ◽  
M.V. Borrachero ◽  
J. Payá ◽  
J.L. Akasaki ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sewage Sludge ◽  
Strength Development ◽  
X Ray Diffraction ◽  
Sewage Sludge Ash ◽  
Dense Microstructure ◽  
Compressive Strength Development ◽  
Physicochemical Characterisation ◽  
Sludge Ash

This paper aimed to evaluate the long-term compressive strength development of the sewage sludge ash/metakaolin (SSA/MK)-based geopolymer. SSA/MK-based geopolymeric mortars and pastes were produced at 25ºC with different SSA contents (0 - 30 wt.%). Compressive strength tests were run within the 3-720 curing days range. A physicochemical characterisation (X-ray diffraction and scanning electron microscopy) was performed in geopolymeric pastes. All the geopolymeric mortars presented a compressive strength gain with curing time. The mortars with all the SSA evaluated contents (10, 20, 30 wt.%) developed a compressive strength over 40 MPa after 720 curing days at 25ºC. The maximum compressive strength of the mortars with SSA was approximately 61 MPa (10 wt.% of SSA), similarly to the reference mortar (100% MK-based geopolymer). The microstructure analyses showed that the SSA/MK-based geopolymer presented a dense microstructure with N-A-S-H gel formation.

Heavy Weight Cement System for Corrosive Environment: Preventing Strength Retrogression and H2S Corrosion

2021 ◽  
Author(s):  
Yulia Ramazanova ◽  
Ilshat Akhmetzianov ◽  
Vasilii Sukhachev ◽  
Alexander Sozonov ◽  
Svetlana Nafikova ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Cement Content ◽  
System Optimization ◽  
Strength Development ◽  
Corrosive Environment ◽  
Heavy Weight ◽  
H2s Corrosion ◽  
Cement System ◽  
Compressive Strength Development

Abstract Well cementing in high temperature and hydrogen sulfide (H2S) corrosive environment presents challenges in preventing cement compressive strength retrogression and selecting weighting agents inert to H2S. This paper presents the development of a cementing system for high pressure high temperature (HPHT) well with bottom hole static temperature in excess of 165°C, a drilling fluid density of 2.19 SG and a high concentration of H2S. A major operator in the Caspian Sea region accepted the cement design and successfully used it on the production liner section of the HPHT well. Cementing of the production liner was complex due to the requirement for a high-density cement system, narrow margin between the pore pressure and frac gradient, HPHT conditions and 18% H2S concentration in the formation fluid. Comprehensive laboratory testing was performed to evaluate the properties of the cement system including measurements of thickening time and compressive strength evaluation using a UCA and destructive method using ultra-HPHT curing chamber for cube sample curing. The presence of H2S limited the use of conventional weighting agents such as hematite and hausmannite, and the high temperature environment dictated the need for quartz silica. These factors required a nonstandard approach to cement blend formulation and flowability assessment. During cement system optimization, the target slurry density was achieved using barite which has a lower density compared to other common weighting agents and significantly reduces cement content in the blend but also is inert to H2S corrosion. A further challenge encountered during cement system optimization was strength retrogression that could not be prevented by the conventional approach of adding 30-40% quartz silica by weight of cement into the system. To overcome strength retrogression, much higher concentrations of silica were required. As a result, the low cement content led to insufficient compressive strength development at liner hanger depth. A solution was found by adding a Vinylamide/Vinylsulfonated polymer (VA/VS) polymer in a certain proportion to the slurry design. Thus, at elevated temperatures, it was observed that the VA/VS polymer tended not to delay compressive strength development while still extending the slurry thickening time. The developed heavy weight cement system was successfully implemented to isolate the 7-in liner on HPHT well. All the stages of job planning, design and execution, along with the slurry optimization process are presented.

Effects of Different Lithium Admixtures on Ordinary Portland Cement Paste Properties

2014 ◽  
Vol 919-921 ◽  
pp. 1780-1789 ◽  
Author(s):  
Yu Hai Deng ◽  
Chang Qing Zhang ◽  
Hai Qiang Shao ◽  
Han Wu ◽  
Nie Qiang Xie
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Lithium Carbonate ◽  
Lithium Hydroxide ◽  
Strength Development ◽  
Lithium Nitrate ◽  
Cement Pastes ◽  
Compressive Strength Development ◽  
Paste Properties

Lithium-based chemicals are known to their signal effect on restraining alkali-silica reaction but uncertain influence on workability and mechanical property in the concrete. The aim of this research is to analyze the effects of three lithium additiveslithium nitrate (LiNO3), lithium hydroxide (LiOH) and lithium carbonate (Li2CO3) at various dosages, with an extensive comparison on fluidities, setting times and compressive strength of cement pastes. The experimental study shows that test results vary with the type of admixture. In general, three conclusions can be made: 1) lithium nitrate and lithium hydroxide can enhance the fluidity of cement paste, but lithium carbonate has opposite effects; 2) all three lithium salts shorten setting time as well as decrease the strength at suitable dosages; 3) the variations in lithium additives dosages have different influence on the cement pastes setting time and compressive strength development.

KUBOTA KNC-03

Alloy Digest ◽  
2010 ◽  
Vol 59 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

scholarly journals The potential use of pumice in mine backfill

2020 ◽  
Vol 1 ◽  
Author(s):  
Mohammed A. Hefni
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Mining Industry ◽  
Strength Development ◽  
Natural Pozzolan ◽  
Mine Backfill ◽  
Natural Pozzolans ◽  
Cemented Backfill ◽  
Compressive Strength Development ◽  
Potential Use

Abstract The use of natural pozzolans in concrete applications is gaining more attention because of the associated environmental, economic, and technical benefits. In this study, reference cemented mine backfill samples were prepared using Portland cement, and experimental samples were prepared by partially replacing Portland cement with 10 or 20 wt.% fly ash as a byproduct (artificial) pozzolan or pumice as a natural pozzolan. Samples were cured for 7, 14, and 28 days to investigate uniaxial compressive strength development. Backfill samples containing 10 wt.% pumice had almost a similar compressive strength as reference samples. There is strong potential for pumice to be used in cemented backfill to minimize costs, improve backfill properties, and promote the sustainability of the mining industry.

High-temperature long-term strength of shells in aggressive media with regard for the mass exchange

2007 ◽  
Vol 43 (2) ◽  
pp. 153-162
Author(s):  
A. M. Lokoshchenko ◽  
D. O. Platonov
Keyword(s):  
High Temperature ◽  
Mass Exchange ◽  
Term Strength
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