scholarly journals Calibration of Material Models against TSTM Test for Crack Risk Assessment of Early-Age Concrete Containing Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
G. M. Ji ◽  
T. Kanstad ◽  
Ø. Bjøntegaard
Keyword(s):  
Risk Assessment ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Restraint Stress ◽  
Early Age ◽  
Material Models ◽  
Early Age Concrete ◽  
Mineral Additives ◽  
Cracking Risk ◽  
Furnace Slag

Making reliable cracking risk assessment involves experimental testing and advanced modeling of the time- and temperature-dependent behavior of the properties, the restraint conditions of the structure, and the external environmental conditions. Mineral additives such as silica fume (SF), blast furnace slag (BFS), and fly ash (FA) have been used extensively in production of high performance concrete in the last decades. The mineral additives such as fly ash and blast furnace slag will reduce the hydration heat during the hardening phase, and the mineral additives also have significant influence on the development of mechanic and viscoelastic properties at early age. Within the NOR-CRACK project, extensive test programs were performed to investigate the material properties related to cracking risk of early-age concrete containing mineral additives. In current paper, the advanced modeling of the heat of hydration, volume changes (autogenous shrinkage and thermal dilation) during hardening, the development of mechanical properties (E-modulus, compressive strength, and tensile strength), and creep/relaxation properties are discussed. Tests were performed in “temperature stress testing machine” (TSTM) to measure the restraint stress, and well-documented material models were verified by performing 1-D analysis of restraint stress development in the TSTM (Ji, 2008).

scholarly journals Numerical Modelling of Field Test for Crack Risk Assessment of Early Age Concrete Containing Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
G. M. Ji ◽  
T. Kanstad ◽  
Ø. Bjøntegaard
Keyword(s):  
Fly Ash ◽  
Wall Structure ◽  
Early Age ◽  
Measured Temperature ◽  
Finite Element Program ◽  
Stress Development ◽  
Thermal Dilation ◽  
Early Age Concrete ◽  
Mineral Additives ◽  
Cracking Risk

The high-strength/high-performance concretes are prone to cracking at early age due to low water/binder ratio. The replacement of cement with mineral additives such as fly ash and blast-furnace slag reduces the hydration heat during the hardening phase, but at the same time, it has significant influence on the development of mechanic and viscoelastic properties of early age concrete. Its potential benefit to minimize the cracking risk was investigated through a filed experiment carried out by the Norwegian Directorate of Roads. The temperature development and strain development of the early age concrete with/without the fly ash were measured for a “double-wall” structure. Based on experimental data and well-documented material models which were verified by calibration of restraint stress development in TSTM test, thermal-structural analysis was performed by finite element program DIANA to assess the cracking risk for concrete structures during hardening. The calculated and measured temperature and strain in the structure had good agreement, and the analysis results showed that mineral additives such as flay ash are beneficial in reducing cracking risk for young concrete. Furthermore, parameter studies were performed to investigate the influence of the two major factors: creep and volume change (autogenous shrinkage and thermal dilation) during hardening, on the stress development in the structure.

scholarly journals Effect of Mineral Admixtures on the Sulfate Resistance of High-Strength Piles Mortar

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3500
Author(s):  
Yanyan Hu ◽  
Linlin Ma ◽  
Tingshu He
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Strength ◽  
Mineral Admixtures ◽  
Quartz Powder ◽  
Sulfate Resistance ◽  
Powder Samples ◽  
Mineral Additives ◽  
Furnace Slag

Pre-stressed high-strength concrete piles (PHCP) are widely used in the building industry in China. The main aim of our research was to investigate the utilization of quartz powder, fly ash, and blast furnace slag as mineral additives to prepare PHCP mortar. The samples were prepared using steam and autoclaving steaming. The influence of minerals on the sulfate resistance of mortar was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. The results showed that when compared to single doped quartz powder samples, samples prepared using fly ash or blast furnace slag improved the sulfate resistance of the PHCP mortar. Furthermore, the resistance to sulfate attack of samples with dual doped quartz powder, fly ash, and blast furnace slag also improved. MIP tests showed that mineral additives can change the pore size distribution after autoclave curing. However, the number of aching holes increased after mixing with 20% quartz powder and caused a decrease in the sulfate resistance.

Early Age Cracking Characteristic of Concrete with Compound Admixtures

2013 ◽  
Vol 325-326 ◽  
pp. 71-74
Author(s):  
Yun Feng Li ◽  
Dong Sheng Zhang ◽  
Li Xu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Test Method ◽  
Mineral Admixture ◽  
Early Age ◽  
Furnace Slag

The shrinkage cracking of concrete plays an important role to the accelerated deterioration and shortening the service life of concrete structures. The mineral admixture will be a perfect component of high performance concrete and its utilization will be a valuable resource for recycling. Early age cracking characteristics of concrete with compound admixtures, such as steel slag, blast furnace slag, fly ash, are studied in this paper using plate test method. The better anti-cracking performance of concrete will be realized when blast furnace slag replacing cement at 30%, steel slag and fly ash as the equal mixture components replacing cement at 30%, three kinds of admixtures replacing cement at 30% under the proper proportion.

Improvement of the early-age reactivity of fly ash and blast furnace slag cementitious systems using limestone filler

2010 ◽  
Vol 44 (2) ◽  
pp. 437-453 ◽  
Author(s):  
Pierre Mounanga ◽  
Muhammad Irfan Ahmad Khokhar ◽  
Rana El Hachem ◽  
Ahmed Loukili
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Early Age ◽  
Limestone Filler ◽  
Cementitious Systems ◽  
Age Reactivity ◽  
Furnace Slag

Influence of Compounded Mineral Admixtures on Shrinkage and Early-Age Cracking Behaviors of Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 738-742
Author(s):  
Xue Fang Wang ◽  
Jian Lan Zheng
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Synergistic Effect ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Early Age ◽  
Volume Stability ◽  
Furnace Slag

Influence of compounded mineral admixtures on shrinkage and early-age cracking behaviors of concrete was studied, based on the fellow factors: fly ash to blast furnace slag(denoted as BSF) ratio, fly ash-metakaolin ratio, BSF-silica fume ratio. Research shows that the Pozzolanic admixtures compounded with cementitious admixtures have complementary and synergistic effect for hydration progress of concrete, which can enhance the volume stability and cracking behaviors of concrete. However, the pozzolanic admixture compounded with other pozzolanic admixture, two pozzolanic admixtures will grab Ca(OH)2 resource. And then if the dosage of mineral admixture is higher, the compounding will result to decrease the volume stability and cracking behaviors of concrete.

Early-Age Heat Evolution and Pore Structure of Portland Cement Blended with Blast Furnace Slag, Fly Ash or Limestone Powder

2009 ◽  
Vol 405-406 ◽  
pp. 242-246
Author(s):  
Jie Zhou ◽  
Guang Ye ◽  
Klaas van Breugel
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Portland Cement ◽  
Pore Structure ◽  
Blast Furnace Slag ◽  
Heat Evolution ◽  
Limestone Powder ◽  
Experimental Investigations ◽  
Early Age ◽  
Furnace Slag

Recently, blast furnace slag, fly ash and limestone powder are increasingly used as blending materials in producing concrete. The use of these materials not only has economical and environmental advantages, but also improves the mechanical properties, durability and workability of concrete. In this paper, the results of experimental investigations on the evolution of hydration heat and the development of microstructure of Portland cement blended with blast furnace slag, fly ash or limestone powder are presented. These results show that three blending materials accelerate the hydration of Portland cement, but result in less heat release during the first 72 hours. The Portland cement with blast furnace slag has a denser pore structure than the others.

scholarly journals New Composite Material for Masonry Repair: Mortar Formulations and Experimental Studies

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 912
Author(s):  
Walid Deboucha ◽  
Ibrahim Alachek ◽  
Jean-Patrick Plassiard ◽  
Olivier Plé
Keyword(s):  
Experimental Study ◽  
Composite Material ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Uniaxial Tensile ◽  
Mineral Additives ◽  
Furnace Slag

The need for retrofitting existing masonry structures is progressively becoming more important due to their continuous deterioration or need to meet the current design requirements of Eurocodes. Textile-Reinforced Mortar (TRM) composite systems have emerged as a sustainable repair methodology suitable for structure retrofitting. Nevertheless, their mechanical performance is still far from being fully investigated. This paper presents an experimental study on the tensile and bond behaviors of a new mortar-based composite consisting of mineral additives, blended cement mortar, and stainless-steel grid. Three different mineral additives (silica fume, fly ash, and blast furnace slag), in binary and ternary systems were used. The experimental study included uniaxial tensile coupon testing on composite specimens and bond tests on composite material applied to clay-brick substrate. The results obtained with the different textile-reinforced cement-based mortars were compared and are discussed here. It was found that, for mortar formulations containing mineral additives—such as fly ash or blast-furnace slag—with high tensile and bond strengths, an adequate adherence between the constituents was obtained. The developed mortar presents mechanical performances equivalent to traditional mortars without additives. The study contributes to the existing knowledge regarding the structural behavior of TRM and promotes the development of a low impact carbon cementitious matrix.

scholarly journals Freeze-Thaw Resistance of Cement Screed with Various Supplementary Cementitious Materials

2019 ◽  
Vol 58 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Ondřej Zobal ◽  
Martin Keppert
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Frost Resistance ◽  
Blast Furnace Slag ◽  
Ceramic Powder ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Freeze Thaw ◽  
Mineral Additives ◽  
Furnace Slag

Abstract This paper describes a study of the effect of partial replacement of ordinary Portland cement (OPC) by various mineral additives in the screed mixtures. Ceramic powder, blast furnace slag and fly ash were gradually employed in increments of 12.5 wt.% up to 50 wt.% to replace OPC. The mixtures were designed to a constant consistency. The influence of mineral additives was evaluated in terms of the air content in the fresh mixtures, the compressive strength, the flexural strength and the freeze-thaw resistance and using non-destructive measurements after 28 and 90 days. The accompanied paste sampleswere analysed using thermogravimetry to monitor the hydration process by means of total bound water content. The decrease in the mechanical properties and the frost resistance of the mixtures with the mineral additives were recorded, because of the necessity for a larger addition of water. According to the valid standards for concrete screed related to the frost resistance, it could be concluded that maximal suitable cement replacement contents are 12.5, 37.5 and 50 wt.% for ceramic powder, fly ash and blast furnace slag, respectively. The freeze-thaw resistance of the studied materials was found to be strongly related to the content of CSH and CAH hydrates.

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