Quantitative evaluation of mineral admixtures on the properties, pore structure, and durability of cement-based composites

2012 ◽  
Vol 19 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Chinlai Lee ◽  
Maochieh Chi ◽  
Ran Huang
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Silica Fume ◽  
Mercury Intrusion Porosimetry ◽  
Cementitious Material ◽  
Mineral Admixtures ◽  
Penetration Test ◽  
Compressive Strength Test ◽  
Testing Data ◽  
Influence Of Water

AbstractThe influence of water/cementitious material ratio, silica fume, and fly ash as partial Portland cement replacement materials on the properties, pore structure, and durability of cement-based composites was evaluated by conducting compressive strength test, mercury intrusion porosimetry test, water absorption, rapid chloride penetration test, and scanning electron microscopy (SEM). Water/cementitious material ratio, and replacement percentage of silica fume and fly ash have significant effects on the pore structure and durability of cement-based composites. Composites with silica fume or fly ash have a denser structure than the control composite on SEM micrographs. Silica fume has about 5–10 times as much effect as fly ash, according to results of multiple linear regression analyses of testing data.

Ultrasound In Situ Testing of early Hydration Process of Supplementary Cementitious Pastes

2011 ◽  
Vol 477 ◽  
pp. 132-135 ◽  
Author(s):  
Zhi Yong Liu ◽  
Yun Sheng Zhang ◽  
Guo Wen Sun ◽  
Qian Jiang ◽  
Wei Wei Zhu
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Hydration Process ◽  
Mineral Admixtures ◽  
Early Hydration ◽  
Water To Cement Ratio ◽  
Influence Of Water ◽  
Binder Ratio ◽  
Water To Binder Ratio

The early hydration process was investigated using ultrasonic monitoring apparatus for pastes made with various mineral admixtures: silica fume (4%, 13%), slag (10%, 30%, 50%, 70%), and fly ash (10%, 30%, 50%). The influence of water to binder ratio (0.23, 0.35 and 0.53) was also studied. The results show that the hydration rate of cementitious material is obviously accelerated with decreasing in water to cement ratio and Silica fume addition, while the reverse phenomenon is observed when fly ash and slag are incorporated.

Microstructure of High Strength Concrete Mercury Intrusion Porosimetry and Thermogravimetry Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 3781-3786 ◽  
Author(s):  
Iqbal Khan Mohammad
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Calcium Hydroxide ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Mercury Intrusion Porosimetry ◽  
High Strength ◽  
Thermogravimetry Analysis ◽  
Mercury Intrusion ◽  
Strength Concrete

Microstructural properties such as pore structure and hydration play a decisive role in determining the properties of a concrete. This paper presents the investigation on pore structure and hydration process of high strength concrete. Pore structure study was conducted using mercury intrusion porosimetry and hydration progress was monitored using thermogravimetry analysis on various blended combinations of cementitious materials incorporating fly ash and silica fume as partial cement replacement. It was found that silica fume refined the pore structure efficiently and reduced the calcium hydroxide content as early as 1 day. All ternary blended systems containing fly ash and silica fume exhibited lower calcium hydroxide content and refined pore structure in comparison to their respective blended pastes.

scholarly journals Predicting Pumpability and Shootability of Crushed Aggregate Wet-Mix Shotcrete Based on Rheological Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kyong-Ku Yun ◽  
Pangil Choi ◽  
Jung Heum Yeon
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Silica Fume ◽  
Steel Fiber ◽  
Wide Spectrum ◽  
Granulated Blast Furnace Slag ◽  
Compliance Testing ◽  
Testing Data ◽  
Crushed Aggregate ◽  
Pump Pressure

This study aims to estimate the pumpability and shootability of wet-mix shotcrete (WMS) made with crushed aggregates and various admixtures such as silica fume, fly ash, ground granulated blast furnace slag (GGBFS), metakaolin, and steel fiber based on rheological properties. The IBB rheometer was employed as an apparatus to measure the rheological properties of freshly mixed shotcrete such as flow resistance and torque viscosity. Results have shown that the use of silica fume and metakaolin led to satisfactory pumpability, whereas mixtures with fly ash and steel fiber failed to meet the pumping criteria at normal pump pressure. The build-up thickness, an indicator to represent shotcrete shootability, was predicted to vary between 68 and 218 mm, demonstrating that the use of admixtures resulted in a wide spectrum of shootability. In particular, the use of metakaolin was found to substantially increase the predicted build-up thickness only with a small replacement. The findings of this study are expected to be used as an easy-to-use guideline for estimating pumpability and shootability of WMS when no compliance testing data is available.

Shrinkage of Blended Cement Pastes with Mineral Additions

2013 ◽  
Vol 539 ◽  
pp. 55-59
Author(s):  
Yi Chen ◽  
Wu Yao ◽  
Dan Jin
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Blended Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Mineral Additions ◽  
By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

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.

Effect of steel slag powder, fly ash, and silica fume on the mechanical properties and durability of cement mortar

2019 ◽  
Vol 9 (9) ◽  
pp. 1049-1054
Author(s):  
Yunxia Lun ◽  
Fangfang Zheng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Mortar ◽  
Steel Slag ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Slag Powder ◽  
Steel Slag Powder

This study is aimed at exploring the effect of steel slag powder (SSP), fly ash (FA), and silica fume (SF) on the mechanical properties and durability of cement mortar. SSP, SF, and FA were used as partial replacement of the Ordinary Portland cement (OPC). It was showed that the compressive and bending strength of steel slag powder were slightly lower than that of OPC. An increase in the SSP content caused a decrease in strength. However, the growth rate of compressive strength of SSP2 (20% replacement by the weight of OPC) at the curing ages of 90 days was about 8% higher than that of OPC, and the durability of SSP2 was better than that of OPC. The combination of mineral admixtures improved the later strength, water impermeability, and sulfate resistance compared with OPC and SSP2. The compressive strength of SSPFA (SSP and SF) at 90 days reached 70.3 MPa. The results of X-ray diffraction patterns and scanning electron microscopy indicated that SSP played a synergistic role with FA or SF to improve the performance of cement mortar.

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.

scholarly journals Application of Automated Image Analysis to the Study of Cement Paste Microstructure

1994 ◽  
Vol 370 ◽  
Author(s):  
David Darwin ◽  
Mohamed Nagib Abou-Zeid
Keyword(s):  
Image Analysis ◽  
Silica Fume ◽  
Cementitious Material ◽  
Automated Image Analysis ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Size Distributions ◽  
Cement Pastes ◽  
Backscattered Electron ◽  
Hydration Phases

AbstractDigital acquisition and analysis of backscattered electron images provide powerful tools for the study of cement-based materials. The techniques can provide useful information on hydration phases, size distributions of unhydrated particles and voids, effects of changes in the watercementitious material ratio and the use of mineral admixtures, and the distribution of microcracks. The results of automated analyses of cement pastes with different water-cement ratios and pastes containing silica fume are presented. The analyses demonstrate that microstructural data vary significantly from image to image, requiring multiple images to limit the effects of scatter. The analyses also indicate that, although the pastes exhibit different degrees of hydration, the size distributions of the unhydrated cement particles are nearly identical. In contrast, the size distribution of larger voids differs significantly as a function of water-cementitious material ratio and with the use of silica fume as a partial replacement for cement. The calcium hydroxide content obtained based on image analysis exceeds but generally parallels that obtained with thermogravimetric analysis. The majority of microcracks in both nonloaded and loaded specimens occur through or adjacent to the lowest density hydration phase.

Sign in / Sign up

Export Citation Format

Share Document