scholarly journals Influence of mineral admixtures on shrinkage deformation of stone from lime solution

2021 ◽  
Vol 18 (2) ◽  
pp. 142-149
Author(s):  
N. N. Shangina ◽  
◽  
T. Yu. Safonova ◽  
Keyword(s):  
Strength Properties ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Cement Stone ◽  
Active Type ◽  
Lime Solution

The analysis of research works devoted to the study of different mineral admixtures influence on development of shrinkage deformation of cement stone is presented.There were studued strength properties and shrinkage deformation of stone from lime building solution based on binder agent with active mineral admixture. The authors give the data on the influence of active type admixture on the change of air shrinkage of stone aged up to 28 days, and the comparison of these date with plain solution content without admixtures has been carried out. It has been established that shrinkage for stone aged 28 days from mixture with metakaolin is 10 percent lower than that of stone of the same age from mixture with microsilica suspension.

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.

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.

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 Mechanical Properties and Microscopic Mechanism of Coral Sand-Cement Mortar

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Luoxin Wang ◽  
Junshuai Mei ◽  
Jing Wu ◽  
Xingyang He ◽  
Hainan Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cement Mortar ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Hardened Cement ◽  
Hydration Reaction ◽  
Microscopic Mechanism ◽  
X Ray ◽  
Volume Stability ◽  
Coral Sand

The workability and mechanical performance of coral sand-cement mortar (coral mortar, for short) and the modification effects of mineral admixtures on the coral mortar were studied in this paper. The results showed that the strength of coral mortar was lower than that of standard mortar, but the strength of coral mortar was improved by compositing with the mineral admixture, which can be attributed to the improvement of the microstructure and interface transition area. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to explore the microscopic mechanism involved in the mechanical properties, volume stability, and hydration of mortar. The analyses revealed that the internal curing effect of coral sand improved the mechanical properties of mortar and its ability to resist shrinkage. The uneven surface of coral sand formed a meshing state of close combination with the hardened cement mortar, which helped to improve the volume stability of mortar. The Ca2+ and Mg2+ ions from coral sand participated in the hydration reaction of cement, which contributed to generating more hydration products. Moreover, the microaggregate filling and pozzolanic effects of fly ash and slag improved the mechanical properties of coral mortar and resistance to chloride ion diffusion.

Study on the Durability of Concrete with Mineral Admixtures to Sulfate Attack by Wet-Dry Cycle Method

2011 ◽  
Vol 295-297 ◽  
pp. 165-169
Author(s):  
Guan Guo Liu ◽  
Jing Ming ◽  
Xiong Wen Zhang ◽  
Ai Bin Ma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Change Environment ◽  
Physical Mechanisms ◽  
Chemical Attack ◽  
Tidal Area

Sulfate attack is one of several chemical and physical mechanisms of concrete deterioration. In actual situation, concrete structures always suffer from the coupled effects of multifactor such as wet-dry cycle and sulfate attack when exposed to tidal area or groundwater level change environment. Partial replacement of cement with mineral admixture is one of the efficient methods for improving concrete resistance against sulfate attack. In this regard, the resistance of concrete with fly ash and slag to sulfate attack was investigated by wet-dry cycle method. The degree of sulfate attack on specimens after different cycles was observed using scanning electron microscopy. The results of compressive strength and percentage of compressive strength evolution factor at various cycling times show an increase in the sulfate resistance of concrete with 60% of fly ash and slag than that only with 40% fly ash. The microstructural study indicates that the primary cause of deterioration of concrete under wet-dry cycle condition is swelling of the sulfate crystal rather chemical attack.

scholarly journals Evaluation of Heat Insulation and Surface Resistivity of Mineral Lightweight Aggregate Concrete(MLAC)

2020 ◽  
Vol 10 (21) ◽  
pp. 7871
Author(s):  
Jung-Nan Chang ◽  
Tung-Tsan Chen ◽  
Chang-Chi Hung ◽  
Her-Yung Wang
Keyword(s):  
Heat Insulation ◽  
Lightweight Aggregate ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Unit Weight ◽  
Lightweight Aggregate Concrete ◽  
Control Group ◽  
K Value ◽  
Aggregate Concrete ◽  
Binder Ratio

In this study, the fixed water/binder ratio is 0.40, four mineral admixtures: fly ash (FA), blast furnace slag (BFS), desulphurization slag (DLS), and glass LED powder (GLP), were added to lightweight aggregate concrete (LWAC), replacing 10% or 30% of the cement content, to study their heat insulation efficiency and engineering performance and to compare the economic impact of mineral admixtures on LWAC. In terms of heat insulation, the thermal conductivity (K value) of the controlled sample was 0.484 kcal/(m.h. °C) and the addition of mineral admixtures changed the concrete unit weight and water absorption ratio, thus reducing the K value by 0.41% to 25.71% and improving the heat insulation. As the mineral admixture hydration products and chemical contents differed, the heat insulation of the LWAC varied as well. The study indicated that the heat insulation is the greatest in concrete with the addition of 30% FA, followed by concrete with the addition of 10% GLP. The addition of mineral admixtures is 30%, the resistivity is 72–455% of the control group, and the resistivity of FA and GLP is higher than the control group. The study is indicated that the proper addition of mineral powder material has an apparent effect on increasing heat insulation efficiency.

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.

Evaluation of Fresh Properties and Rheology of Mortar Using Carbon-Free Fly Ash and Normal Fly Ash

2020 ◽  
Vol 1005 ◽  
pp. 76-81
Author(s):  
Ghawsaddin Nazari ◽  
Shunya Yamanaka ◽  
Shigeyuki Date
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Great Influence ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Fresh Properties ◽  
Initial Setting Time ◽  
Usual Solution ◽  
Initial Setting ◽  
Flow Loss

Usage of mineral admixture and chemical admixture in concrete or mortar is a usual solution to reach full compaction, particularly where reinforcement blockage and lack of skilled labor happen. In this paper effect of mineral admixtures (Carbon-free fly ash, hereafter CfFA, and normal fly ash) on fresh properties and rheology of mortar have been investigated. As a result, it was confirmed that CfFA increased significantly the fluidity and air content of mortar in comparison to normal fly ash, both in 15% and 30% replacement; however, the flow loss and air stability within one hour were almost equal. In addition, the initial setting time has also been affected by variation of materials. The two mixing of 30% and 15% of CfFA had a shorter setting time in comparison to the mortar with normal fly ash. Furthermore, CfFA based mortar had a great influence on rheology of mortar. Compared to normal fly ash, CfFA Considerably decreased the plastic Viscosity and increased the productivity of the mortar, both in non-vibrated and vibrated condition, particularly those with 30% replacement.

A Research on the Anti-Sulfate Corrosion Effects of the Concrete Mixed with Complex Multi-Mineral Admixture

2011 ◽  
Vol 71-78 ◽  
pp. 755-759
Author(s):  
Ying Tang ◽  
Guo An Wang
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Significant Influence ◽  
Ash Content ◽  
Performance Characteristics ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Corrosion Effect ◽  
Slag Content

This paper is focused on the method for improving capability of anti-sulfate corrosion of concrete. Based on the performance characteristics of mineral admixture, propose a method that mixing concrete with complex multi-mineral admixture to improve the effect of anti-sulfate corrosion. Finally, the ability of anti-sulfate corrosion and anti-dry-wet cycle, in different case, is studied and compared. The results show that concrete mixed with complex multi-mineral admixture is advantageous to improve the anti-sulfate corrosion effects of the concrete. The proportion of mineral admixtures has significant influence on the anti-sulfate corrosion effect. As the silica fume and slag content increased, the fly ash content decreased, the ability of anti-sulfate corrosion enhanced.

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