scholarly journals Research on Curing Water Demand of Cementing Material System Based on Hydration Characteristics

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7098
Author(s):  
Wang Yao ◽  
Baolin Guo ◽  
Zhenyu Yang ◽  
Xingxing Yang ◽  
Yongzhi Guo ◽  
...  
Keyword(s):  
Water Demand ◽  
Pure Water ◽  
Bound Water ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Concrete Durability ◽  
Material System ◽  
Early Hydration ◽  
Cover Concrete ◽  
Cementing Material

The performance of cover concrete is acknowledged as a major factor governing the degradation of concrete structures. Curing plays a vital role in the development of concrete durability. The effects of different water-binder ratios and mineral admixtures on the curing water demand of concrete were studied by the surface water absorption test. Combined with the characteristics of the hydration heat and chemically bound water of the composition cementing material system, the law of variation for curing water demand was analyzed. The results show that the addition of mineral admixtures can reduce the early hydration rate and hydration exothermic characteristics, and the hydration degree decreases with the increase of mineral admixtures. Due to the filling effect and active effect, the addition of fly ash (FA) and ground granulated blast slag (GGBS) reduces the curing water demand. The curing water demand of cover concrete decreases with the increase of mineral admixture content, and the curing water demand of pure water is the maximum and that of mix FA and GGBS is the minimum. Moreover, there is a strong correlation between the cumulative curing water demand and the chemically bound water content, indicating that the power of water migration mainly comes from the hydration activity of the cementing material system. The results provide a theoretical basis for the fine control of a concrete curing system.

Analytical Study on the Flexural Behavior of Reinforced Concrete Beam with Mineral Admixture under Calcium Leaching Degradation

2018 ◽  
Vol 940 ◽  
pp. 123-127
Author(s):  
Il Sun Kim ◽  
Yoon Suk Choi ◽  
Chan Kyu Lee ◽  
Eun Ik Yang
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Pure Water ◽  
Reinforced Concrete Beam ◽  
Mineral Admixture ◽  
Flexural Behavior ◽  
Mineral Admixtures ◽  
Finite Element Program ◽  
Calcium Leaching ◽  
Element Program

Calcium leaching degradation could be happened in reinforcement concrete member due to the contact with pure water in underground condition. Thus, it is needed to evaluate the resistance of calcium leaching for concrete mixed with mineral admixtures. So, in this paper, to evaluate the flexural behavior in RC member with mineral admixture under calcium leaching degradation, we investigated the effect of calcium leaching using the non-linear finite-element program. From the results, the load capacity and flexible rigidity of a degraded RC member decrease when the degradation level increases with leaching period. And, regardless of the type of mineral admixtures, finite-element-method analysis effectively showed the characteristics of calcium leaching damaged RC beam.

scholarly journals Effects of Expansive Agents on the Early Hydration Kinetics of Cementitious Binders

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1900 ◽  
Author(s):  
Miao Miao ◽  
Qingyang Liu ◽  
Jian Zhou ◽  
Jingjing Feng
Keyword(s):  
Fly Ash ◽  
Hydration Heat ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Hydration Reaction ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Expansive Agent ◽  
Mechanical Performances ◽  
Kinetics Of

The addition of expansive agents could overcome the main disadvantages of raw concrete including high brittleness and low tensile strength. Few studies have investigated the early hydration kinetics of expansive cementitious binders, though the findings from the early hydration kinetics are helpful for understanding their technical performances. In this study, mixtures of 3CaO•3Al2O3•CaSO4 and CaSO4 (i.e., ZY-type™ expansive agent) with different proportions of mineral admixtures (e.g., fly ash and slag) were added into cement pastes to investigate the early hydration kinetics mechanism of expansive cementitious binders. Early hydration heat evolution rate and cumulative hydration heat were measured by isothermal calorimeter. Kinetic parameters were estimated based on the Krstulovic–Dabic model and Knudsen equations. Mechanical performances of expansive cementitious binders were tested in order to evaluate if they met the basic requirements of shrinkage-compensating materials in technical use. The early hydration heat released from cementitious binders containing ZY-type™ expansive agent was much greater than that released by pure cement, supporting the idea that addition of the expansive agent would improve the reaction of cement. The early hydration kinetic rates were decreased due to the reactions of the mineral admixture (e.g., fly ash or slag) and the ZY-type™ expansive agent in the cement system. The hydration reaction of cementitious binders containing ZY-type™ expansive agent obeyed the Krstulovic–Dabic model well. Three processes are involved in the hydration reaction of cementitious binders containing ZY-type™ expansive agent. These are nucleation and crystal growth (NG), interactions at phase boundaries (I), and diffusion (D). The 14-day expansion rates of cementitious binders containing ZY-type™ expansive agent are in the range of 2.0 × 10−4 to 3.5 × 10−4, which could meet the basic requirements of anti-cracking performances in technical use according to Chinese industry standard JGJ/T 178-2009. This study could provide an insight into understanding the effects of expansive agents on the hydration and mechanical performances of cementitious binders.

scholarly journals Metakaolin Influence on Concrete Durability Properties

2019 ◽  
Vol 8 (11) ◽  
pp. 1109-1111
Keyword(s):  
Water Absorption ◽  
Mineral Admixture ◽  
Engineering Properties ◽  
Mineral Admixtures ◽  
Concrete Durability ◽  
Acid Attack ◽  
Initial Water ◽  
Durability Properties ◽  
Weight Losses ◽  
Permanence Properties

Mineral admixtures are being used today almost in all concretes partially, to improve workability, engineering properties and also to enhance durability of the concrete. These admixtures are industrial by-products. In the present study, mineral admixture such as metakaolin (MK) is replaced partially in cement to investigate permanence properties of concrete in terms of initial water absorption, final water absorption and confrontation to acid attack. Inorder to identify the durability properties, concrete of M30 grade was prepared. The mineral admixture content was varied from 0% to 30% by volume of cement with 10% gradient. In acid attack, 3% H2SO4 solution is used for curing of specimens and the corresponding weight losses (%) were evaluated for curing periods of 7 days, 14 days and 28 days. Both initial and final water absorptions of the metakaolin-modified concrete have been improved when metakaolin content was increased up to 10% advantageously. And, also weight loss was decreased when metakaolin content varied from 0% to 30%.

Study on High Amount Mineral Admixtures Concrete Performance

2013 ◽  
Vol 357-360 ◽  
pp. 667-670
Author(s):  
Zhi De Huang
Keyword(s):  
Chloride Ion ◽  
Cementitious Material ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Material System ◽  
Ion Permeability ◽  
Main Research ◽  
Binder Ratio ◽  
Marine Concrete ◽  
Water Binder Ratio

Depended on Qingdao Bay Bridge construction, large amount mineral admixture replacing cement has been conducted systematical research aiming at marine concrete, main control index is chloride ion permeability resistance. The main research contents concrete working, mechanical properties and chloride ion permeability resistance at low water binder ratio and large amounts mineral admixture. Measures and adjustment are proposed for marine concrete construction control and cementitious material system that using amount mineral admixtures and low water binder ratio.

Effects of Fly Ash and Granular Blast-Furnace Slag on Development Rate of Strength of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 371-375
Author(s):  
Ji Wei Cai ◽  
Si Jia Yan ◽  
Gong Lei Wei ◽  
Lu Wang ◽  
Jin Jin Zhou
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Development Rate ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Conventional Concrete ◽  
Enhancing Effect ◽  
Substitution Content ◽  
Furnace Slag

Fly ash (FA) and granular blast-furnace slag (GBFS) are usual mineral admixtures to conventional concrete, and their contents substituted for Portland cement definitely affect development rate of strength of concrete. C30 and C60 concrete samples with FA and/or GBFS were prepared to study the influence of substitution content of the mineral admixtures on 3 d, 7 d and 28 d strength. The results reveal that the development rate of strength in period from 3 d to 7 d gets slow with increasing content of mineral admixtures except for concrete with only GBFS less than 20%. In the case of substituting FA as the only mineral admixture for part of cement, the development rate of strength of C30 concrete in period from 7 d to 28 d keeps roughly constant even that of C60 concrete increases. When substituting mineral admixtures in the presence of GBFS for cement within experimental range, the development rate of strength in period from 7 d to 28 d gets fast with increasing substitution content. The enhancing effect of combining FA and GBFS occurs in period from 7 d to 28 d for both C30 and C60 concretes (FA+GBFS≤40%), even occurs in period from 3 d to 7 d for C60 concrete. Based on 7 d strength and the development rate, 28 d strength of concrete can be predicted accurately.

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.

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.

scholarly journals Ideal supplementary cementing material – Metakaolin: A review

2020 ◽  
Vol 11 (1) ◽  
pp. 58-65
Author(s):  
G. Lizia Thankam ◽  
Neelakantan Thurvas Renganathan
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Mineral Admixture ◽  
Homogeneous Material ◽  
Interfacial Zone ◽  
Supplementary Cementing Materials ◽  
Pozzolanic Material ◽  
Efficient Packing ◽  
Cementing Material ◽  
Zone Microstructure

AbstractThough being an ancient trend, usage of the homogeneous material cement in the construction industry is steadily getting eradicated with the springing up of supplementary cementing materials (SCM). Metakaolin is an imminent mineral admixture extracted from the mineral ore kaolinite, which enhances the interfacial zone by more efficient packing at the cement paste-aggregate particle interface, thus reducing the bleeding and producing a denser, more homogeneous transition zone microstructure. This paper depicts the various repercussions of the pozzolanic material metakaolin in the fresh and hardened properties of concrete when replaced with cement in finite amount. Also, it states the behavior of high-performance concrete and self-compacting concrete with metakaolin.

Comparative Study of Metakaolin and Zeolite Tuff Influence on Properties of High-Strength Concrete

2022 ◽  
Author(s):  
Leonid I. Dvorkin ◽  
Vadim Zhitkovsky ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi
Keyword(s):  
High Strength ◽  
Economic Feasibility ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
High Dispersion ◽  
High Dispersity ◽  
Energy Consuming ◽  
Effective Use ◽  
Pozzolanic Properties ◽  
Zeolite Tuff

Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances to resources and energy consuming mineral admixtures like metakaolin and silica fume. The deposits of zeolites are developed in Transcarpathia (Ukraine), USA, Japan, New Zealand, Iceland and other countries. It is known that zeolite tuffs exhibit pozzolanic properties and are capable to substitution reactions with calcium hydroxide.However, the high dispersion of zeolite rocks leads to a significant increase in the water consumption of concrete. Simultaneous introduction of zeolite tuffs with superplasticizers, which significantly reduce the water content, creates the preconditions for their effective use in high-strength concrete.Along with dehydrated (calcined) zeolite, natural (non-calcined) zeolite expresses itself as an effective mineral admixture of concrete. When using non-calcined zeolite, the effect of increasing in compressive strength at the age of 3 and 7 days is close to the effect obtained when using dehydrated zeolite: 8-10% and 10- 12%, respectively, and 28 days the strength growth is 13-22%. The use of non-calcined zeolite has a significant economic feasibility, so it certainly deserves attention. There were compared the effect of zeolite to metakaolinThe results of the research indicate that the use of composite admixtures, consisted of calcined (non-calcined) zeolite tuff of high dispersity and superplasticizer of naphthalene formaldehyde type, allows to obtain concretes classes C50…C65.

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