scholarly journals Influence of Steam Curing Method on the Performance of Concrete Containing a Large Portion of Mineral Admixtures

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mengyuan Li ◽  
Qiang Wang ◽  
Jun Yang
Keyword(s):  
Chloride Ion ◽  
Mineral Admixtures ◽  
Strength Development ◽  
Steam Curing ◽  
Chloride Permeability ◽  
Curing Conditions ◽  
Volume Stability ◽  
Ettringite Formation ◽  
The Impact ◽  
Reaction Degree

A comparison was made between the impact of raising the thermostatic temperature and the impact of prolonging the thermostatic time on the performance of steam-cured concrete containing a large portion of fly ash (FA) or ground granulated blast furnace slag (GGBS) by analysing the form removal strength, chemically combined water content, reaction degree, strength development, chloride permeability, and volume stability. For the materials and test conditions reported in this study, raising the thermostatic temperature is more favourable for concrete containing FA, as indicated by the significantly higher form removal strength and the higher growth of reaction degree of FA compared with prolonging the thermostatic time. With an increase in the thermostatic temperature, the hydration degree of a binder containing FA or GGBS initially increases and subsequently decreases. Although concrete containing FA can obtain satisfactory form removal strength with steam curing at 80°C, the late strength development of concrete containing FA is slow for the same curing conditions. The effect of the late performance of resistance to chloride ion permeability improved by FA is better than the effect improved by GGBS. The risk of destroying the structure of concrete containing a large portion of FA or GGBS due to delayed ettringite formation (DEF) is minimal when specimens were steam-cured at 80°C.

Effect of Mineral Admixtures and Water/Binder Ratios on the Resistance to the Chloride Ions Penetration into Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 758-761
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Chloride Ion ◽  
Test Methods ◽  
Chloride Ions ◽  
Mineral Admixtures ◽  
Chloride Permeability ◽  
Furnace Slag

In this study, concrete prisms were made with three mineral admixtures: fly ash, blast furnace slag or silica fume and with three water-to-binder ratios(w/b). Chloride penetration was measured by the rapid chloride permeability test (RCPT)-ASTM C1202, 150-days ponding test and alternate wetting and drying test by cyclic loading with salt solution and oven drying, and the results by the three test methods were compared. This paper discussed the effects of mineral admixtures and w/b on the concrete chloride permeability. Blending concrete with blast furnace slag, fly ash or silica fume was beneficial with regard to the resistance against chloride ion penetration. Concrete specimens with lower w/b showed lower chloride permeability.

Experimental Study on Permeability Resistant and Pore Structure of High Content Mineral Admixtures of HPC

2013 ◽  
Vol 860-863 ◽  
pp. 1232-1236
Author(s):  
Hai Cheng Yang
Keyword(s):  
Pore Structure ◽  
Water Absorption ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Mineral Admixtures ◽  
Chloride Permeability ◽  
Influence Of Water ◽  
Marine Engineering ◽  
Curing Age

The influence of water absorption and chloride permeability for high content mineral admixtures HPC with W/B ratio and curing age have been tested, pore structure of concrete have been tested by mercury intrusion method (MIP) and the relationship with permeability resistance also have been analyzed. The research show that chloride ion penetration resistance and water absorption decreased significantly with the extension of curing age and low W/B ratio. Marine engineering high-performance concrete with double adding fly ash and blast furnace slag has excellent resistance to chloride ion permeability. The pore structure of concrete can optimize by double adding and the pore distribution are more reasonable.

Evolution of Capillary Porous Structure in Steam Curing Concrete with Mineral Admixtures

2012 ◽  
Vol 450-451 ◽  
pp. 3-7
Author(s):  
Ming Fang Ba ◽  
Chun Xiang Qian
Keyword(s):  
Fly Ash ◽  
Porous Structure ◽  
Evolution Model ◽  
Mineral Admixtures ◽  
Porous Structures ◽  
Capillary Porosity ◽  
Hydration Degree ◽  
Steam Curing ◽  
Curing Conditions ◽  
Cast Concrete

The capillary porous structures of the pre-cast concrete with different initial steam-curing duration were analyzed with MIP techniques. Then the hydration degree of cement, fly ash and slag in pre-cast concrete versus time were obtained respectively by combing the hydrochlorides and EDTA selecting dissolution methods, based on which the corresponding evolution of capillary porosity was determined. The comparison between calculated results and experimental capillary porosity showed that the proposed evolution model of capillary porosity could be adopted to reveal the developing trend of capillary porosity of pre-cast concrete with fly ash and slag under certain curing conditions

scholarly journals Curing Effects on High-Strength Concrete Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Afaf M. O. Wedatalla ◽  
Yanmin Jia ◽  
Abubaker A. M. Ahmed
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Chloride Diffusion ◽  
Steam Curing ◽  
Curing Conditions ◽  
Strength Concrete ◽  
Concrete Properties ◽  
Curing Methods ◽  
The Impact

This study was conducted to investigate the impact of hot and dry environments under different curing conditions on the properties of high-strength concrete. The concrete samples were prepared at a room temperature of 20°C and cured under different curing conditions. Some specimens underwent standard curing from 24 h after casting until the day of testing. Some specimens underwent steam curing in a dry oven at 30°C and 50°C after casting until the day of testing. Other specimens were cured for 3, 7, 21, and 28 days in water and then placed in a dry oven at 30°C and 50°C and tested at the age of 28 days, except for the specimens that were cured for 28 days, which were tested at the age of 31 days, to study the effect of curing period on the strength of concrete exposed to dry and hot environments after moist curing. The effects of hot and dry environments on high-strength concrete with different water/binder ratios (0.30, 0.35, and 0.40), using (30%) fly ash for all mixes, and (0%, 5%, and 10%) silica fume with the binder (450, 480, and 520 kg), respectively, were separately investigated, and the effects of curing under different conditions were evaluated by measuring the compressive strength, flexural strength, microhardness, and chloride diffusion and by assessing the concretes’ microstructure. The relationships between these properties were presented. A good agreement was noted between the concrete compressive strength and concrete properties at different temperatures, curing periods, and curing methods.

Study on the Influence of Painting Processes on the Protective Property of Concrete Coating

2012 ◽  
Vol 509 ◽  
pp. 88-92
Author(s):  
Yan Zheng ◽  
Qian Jin Mao ◽  
Ya Li Wang ◽  
Zi Ming Wang ◽  
Su Ping Cui
Keyword(s):  
Penetration Depth ◽  
Chloride Ion ◽  
Chloride Permeability ◽  
Acrylic Emulsion ◽  
Effective Measure ◽  
Water Based ◽  
Protective Performance ◽  
The Impact ◽  
The Relationship ◽  
Durability Of Concrete

With the development of construction project the durability of concrete is becoming more and more prominent, and surface coating is an effective measure to enhance the durability of concrete. Water-based silicone acrylic emulsion coating and water-based fluorocarbon resin coating were chose as prime and topcoat respectively. The impact of the coating’s thickness and viscosity on the durability of concrete and the relationship between the viscosity of the coating and its penetration depth were testified by chloride ion permeability-resistance property of concrete. The results show that thickness is proportional to the protective performance of the coating, and the penetration depth highly depends on viscosity. And the result of coating-4 viscosity method shows that samples with viscosity between 15 and 25 seconds have better chloride permeability resistance.

scholarly journals Effect of Curing Conditions on the Strength Development of Alkali-Activated Mortar

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1455
Author(s):  
Lijuan Kong ◽  
Zirui Fan ◽  
Wenchen Ma ◽  
Jiatao Lu ◽  
Yazhou Liu
Keyword(s):  
Volume Density ◽  
Water Evaporation ◽  
Strength Development ◽  
Steam Curing ◽  
Curing Conditions ◽  
Granulated Blast Furnace Slag ◽  
Boltzmann Function ◽  
Time Required ◽  
Furnace Slag ◽  
Alkali Activated

In this study, the strength development and microstructure evolution of alkali-activated fly ash (AAF), granulated blast furnace slag (AAG), and metakaolin (AAM) mortars under standard curing, steam curing, and oven curing conditions were investigated. The results show that 80 °C steam curing was more suitable for AAF mortar. Although oven curing was not as good as steam curing under the same temperature, the water evaporation increased the volume density of the N-A-S-H gel and refined the pore structure. For AAG mortar, the strength developed according to a Boltzmann function with time under steam curing conditions, which increased rapidly in the first 8 h, but grew little after about 15 h. Moreover, the strength development was severely limited by steam curing at 60 °C, and decreased under oven curing conditions due to the formation of microcracks that were induced by temperature stress and chemical shrinkage. For AAM mortar, the strength developed according to an Allometric power function with time under steam curing conditions, and the N-A-S-H gel formed in AAM had a higher polymerization degree and denser structure compared to that in AAF. The compressive strength of AAM mortar was 31.7 MPa after 80 °C steam curing for 4 h, and the standard curing time required to reach the same strength was less than 24 h, indicating that the standard curing was more suitable.

The impact of Fe dosage on the ettringite formation during high ferrite cement hydration

2020 ◽  
Author(s):  
Dawei Wan ◽  
Wenqin Zhang ◽  
Yong Tao ◽  
Zonghua Wan ◽  
Fazhou Wang ◽  
...  
Keyword(s):  
Cement Hydration ◽  
Ettringite Formation ◽  
The Impact

Permeability of Lightweight Aggregate Concrete with Mineral Admixture

2013 ◽  
Vol 857 ◽  
pp. 105-109
Author(s):  
Xiu Hua Zheng ◽  
Shu Jie Song ◽  
Yong Quan Zhang
Keyword(s):  
Pore Structure ◽  
Lightweight Concrete ◽  
Chloride Ion ◽  
Lightweight Aggregate ◽  
Total Porosity ◽  
Normal Weight ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

This paper presents an experimental study on the permeability and the pore structure of lightweight concrete with fly ash, zeolite powder, or silica fume, in comparison to that of normal weight aggregate concrete. The results showed that the mineral admixtures can improve the anti-permeability performance of lightweight aggregate concrete, and mixed with compound mineral admixtures further more. The resistance to chloride-ion permeability of light weight concrete was higher than that of At the same strength grade, the anti-permeability performance of lightweight aggregate concrete is better than that of normal weight aggregate concrete. The anti-permeability performance of LC40 was similar to that of C60. Mineral admixtures can obviously improve the pore structure of lightweight aggregate concrete, the total porosity reduced while the pore size decreased.

Influence of Curing Conditions on the Impact of Natural Aggregate Coatings on Concrete Performance

2011 ◽  
Vol 2232 (1) ◽  
pp. 25-33
Author(s):  
Jose F. Muñoz ◽  
Jacob B. Effinger ◽  
M. Isabel Tejedor ◽  
Marc A. Anderson ◽  
Steven M. Cramer
Keyword(s):  
Curing Conditions ◽  
Natural Aggregate ◽  
The Impact

scholarly journals Effectiveness of Using Active Games for Strength Development in 10-Year-Old Boys at the Initial Training Stage in Kyokushin Karate

2021 ◽  
Vol 21 (1) ◽  
pp. 84-89
Author(s):  
Svitlana Marchenko ◽  
Bahtiiar Satdyiev
Keyword(s):  
Strength Development ◽  
Left Hand ◽  
Hand Grip ◽  
Standing Long Jump ◽  
Training Stage ◽  
Fitness Indicators ◽  
Long Jump ◽  
The Right ◽  
Grip Test ◽  
The Impact

The objective of the study was to examine the level of strength fitness indicators of 10-year-old boys who do Kyokushin Karate, and experimentally test the effectiveness of the impact of play techniques on the dynamics of strength development. Materials and methods. The study involved 40 10-year-old boys. The children and their parents were informed about all the features of the study and gave their consent to participate in the experiment. To achieve the objective set, the following research methods were used: analysis of scientific and methodological literature, pedagogical testing, and methods of mathematical statistics for processing research results. Results. There were the biggest changes in the results of the tests “Standing long jump” by 15.9% (р < 0.001), “Sit-ups in 30 s” by 16.0% (р < 0.001), “Pull-ups” by 18.3% (р < 0.001), and “Bent arm hang” by 15.6% (р < 0.001). The experimental group boys’ result of the “Standing long jump” changed from low to above average. The lowest increase in results was observed in the “Right hand grip test” by 7.2% (р < 0.001), “Left hand grip test” by 6.9% (р < 0.001), and“Push-ups” by 11.8% (р < 0.001). Conclusions. The initial level of the boys’ strength fitness is sufficient and conforms to age norms. Most of them had an average – 30.36%, an above average – 19.64%, and a high – 23.21% level of strength abilities development. The data obtained give reason to recommend that teachers and coaches use active games aimed at developing strength. As a result of using play load (5 games, 3 repetitions with rest intervals of 40 s), there was a statistically significant increase in strength indicators (р < 0.001).

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