Hydration and physical characteristics of ultrahigh-volume fly ash-cement systems with low water/binder ratio

2018 ◽  
Vol 161 ◽  
pp. 509-518 ◽  
Author(s):  
Jing Yu ◽  
Gengying Li ◽  
Christopher K.Y. Leung
Keyword(s):  
Fly Ash ◽  
Physical Characteristics ◽  
Binder Ratio ◽  
Water Binder Ratio

scholarly journals Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Hong-zhu Quan ◽  
Hideo Kasami
Keyword(s):  
Fly Ash ◽  
Experimental Studies ◽  
Drying Shrinkage ◽  
Replacement Ratio ◽  
Fly Ash Concrete ◽  
Air Content ◽  
Carbonation Resistance ◽  
Binder Ratio ◽  
Water Binder Ratio

In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

Influence of the Fly-Ash Content of Concrete at Low Water-Binder Ratio on Hydration Degree of Binders and Cement

2011 ◽  
Vol 250-253 ◽  
pp. 445-449
Author(s):  
Li Wei Xu ◽  
Jian Lan Zheng
Keyword(s):  
Fly Ash ◽  
Temperature Rise ◽  
High Performance Concrete ◽  
Ash Content ◽  
Adiabatic Temperature ◽  
Mineral Admixture ◽  
Hydration Degree ◽  
Adiabatic Temperature Rise ◽  
Binder Ratio ◽  
Water Binder Ratio

The hydration degree of binders and cement is investigated by measuring the adiabatic- temperature rise of concrete at low water-binder ratio with different fly-ash content. The results denote that, with a constant water-binder ratio, both of the hydration degree of binders and that of cement decrease with the increasing fly-ash content in the early stage. In a later stage, however, the hydration degree of cement increases with the increasing fly-ash content and the hydration degree of binders peaks when the fly-ash content is 35%. Fly ash is one of the mineral admixture of which high-performance concrete is made up. It brings down the rise of concrete temperature significantly and helps solve the problems of shrinkage and crack of concrete structure. Because the hydration mechanism in common concrete is different from that in concrete with low water-binder ratio, and the hydration environment is different between concrete and cement pastes, to determine the adiabatic-temperature rise of concrete directly conforms to the actual situation. The adiabatic-temperature rise, adiabatic-temperature-rise rate, hydration degree of both binders and cement are investigated by measuring adiabatic-temperature rise of concrete with different fly-ash content.

Modeling the Heat of Hydration of Concrete Incorporating Fly Ash

2016 ◽  
Vol 705 ◽  
pp. 332-337 ◽  
Author(s):  
Zheng Gang Lu ◽  
Xiu Xin Wang
Keyword(s):  
Fly Ash ◽  
Temperature Rise ◽  
Heat Of Hydration ◽  
Hyperbolic Type ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Rise ◽  
Equivalent Age ◽  
Binder Ratio ◽  
Water Binder Ratio ◽  
Release Coefficient

The hydration evolution of concrete with different water-binder ratios and fly ash replacement percentages are studied by experimental investigation. Based on equivalent age concept, the effect of water-binder ratio as well as fly ash dosage on the ultimate temperature rise and heat release coefficient are analyzed with the hyperbolic-type calculating model of adiabatic temperature rise adopted. It is indicated that the adiabatic temperature rise will be reduced with the increase of water-binder ratio and the incorporation of fly ash. The hydration evolution process will be accelerated with the decrease of water-binder ratio, but slowed down when the amount of fly ash is enhanced.

Experimental Study on Workability and Strength of Green High Performance Concrete with High Volume Fly Ash

2013 ◽  
Vol 859 ◽  
pp. 52-55 ◽  
Author(s):  
Yong Qiang Ma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Ash Content ◽  
Splitting Tensile Strength ◽  
Binder Ratio ◽  
Water Binder Ratio

A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.

Study on Tensile Creep Characteristics of High Strength Concrete

2016 ◽  
Vol 835 ◽  
pp. 535-541
Author(s):  
Guan Guo Liu ◽  
Guo Rong Zhang ◽  
Yun Sheng Zhang ◽  
Lu Lu
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Creep Testing ◽  
Tensile Creep ◽  
Free Shrinkage ◽  
Inhibition Effect ◽  
Creep Characteristics ◽  
Binder Ratio ◽  
Water Binder Ratio

A set of concrete tensile creep testing apparatus was constructed. The tensile creep characteristics of concrete under different loading ages (1d, 3d and 7d), different water-binder ratio (0.29, 0.33 and 0.37) and different fly ash proportion (0%, 20% and 40%) were researched. The results show that tensile creep increases with increasing of water-binder ratio obviously as well as with decreasing of loading ages. The tensile creep is inhibited by addition of fly ash, and the inhibition effect increases with the increase of fly ash proportion. Free shrinkage is counteracted 42%~62% by tensile creep. The internal tension of concrete is effectively relieved so that the possibility of cracking of concrete is decreased at early ages.

scholarly journals Early Strength Development of Soft Clay Stabilized by One-Part Ground Granulated Blast Furnace Slag and Fly Ash-Based Geopolymer

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiyao Zheng ◽  
Jun Wu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Soft Clay ◽  
Strength Development ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio ◽  
Early Strength ◽  
Furnace Slag ◽  
Water Binder Ratio

One-part or “just add water” geopolymer is a cementitious material, which is friendly to environment and users in applications. However, the mechanical behavior of the soft soil stabilized by one-part geopolymer is not well acknowledged. In this study, soft clay was stabilized with ground granulated blast furnace slag (GGBFS) and fly ash (FA)-based geopolymer, which is a mixture of solid aluminosilicate precursor (Al-Si raw materials: GGBFS and FA), solid alkali activator, and water. The objective was to adopt one-part geopolymer as an alternative soil binder to completely replace ordinary Portland cement (OPC) for stabilizing the soft clay and evaluate the effect of the factors (i.e., GBFS/FA ratio in Al-Si precursor, activator/Al-Si precursor ratio, and water/binder ratio) that influenced the early strength. Results showed that the increase of the FA content in the Al-Si precursor increased the unconfined compressive strength (UCS) values significantly through the geopolymerization process. The highest UCS values were achieved with 90% GGBFS to 10% FA in the precursor when the activator/precursor and water/binder ratio is 0.15 and 0.7, respectively. The UCS values of geopolymer-stabilized clay could reach 1.5 MPa at 14 days at ambient temperature, which is much higher than that of OPC-stabilized clay. The microstructure and mineralogy analyses indicated that the prolific hydration products, such as calcium silicate hydrate (C-S-H), calcium aluminum hydrate (C-A-H), and calcium aluminum silicate hydrate (C-A-S-H), contributed greatly to strengthen the soft clay by forming the soil skeleton and infilling among clay particles, while sodium aluminosilicate (N-A-S-H) gel is only served to fill the part of porosities in the soil and cannot effectively enhance the UCS of the one-part geopolymer-stabilized soft clay. This paper results suggested that one-part GGBFS-FA–based geopolymers have the potential to replace OPC in the manufacture of stabilized soft clay.

scholarly journals EFFECTS OF MIX PROPORTION ON ELECTRICAL RESISTIVITY OF CONCRETE WITH FLY ASH

2017 ◽  
Vol 7 (2) ◽  
pp. 53-65
Author(s):  
Su Wai Hnin ◽  
Pakawat Sancharoen ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Fly Ash ◽  
Chloride Penetration ◽  
Mix Proportion ◽  
Binder Ratio ◽  
Saturated Concrete ◽  
Paste Content ◽  
Water Saturated ◽  
Water Binder Ratio

The aim of this paper is to investigate the effects of mix proportion on electrical resistivity of concrete with fly ash. The electrical resistivity of concrete is measured by using four Wenner probes. The varied parameters in this study were water/binder ratio, fly ash content, and paste content. Electrical resistivity of water-saturated concrete at several different ages was studied and compared with compressive strength and rapid chloride penetration. Based on experimental results, a good relationship was obtained between results of compressive strength and rapid chloride penetration with electrical resistivity of concrete. The results of this study can be applied further to predict electrical resistivity of concrete when mix proportions are provided. According to the results, lower water/binder ratio concrete had higher resistivity than those with higher water/binder ratios. When cement was replaced at 40% by fly ash, electrical resistivity increased four times when compared to that of OPC concrete.

An Abrasion Damage of Fly Ash Concretes Previously Subjected to Scaling

2016 ◽  
Vol 258 ◽  
pp. 587-590
Author(s):  
Aneta Nowak-Michta
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Abrasion Resistance ◽  
Air Entrainment ◽  
Binder Ratio ◽  
Abrasion Damage ◽  
Water Binder Ratio ◽  
Class F

Effect of quantity and quality of fly ash and compressive strength of concretes with their addition on abrasion resistance previously subjected to scaling is analyzed in the paper. The abrasion resistance was measured in Böhme test according to EN 1338: 2005. The cement was replaced with 20, 35, and 50% of Class F siliceous fly ash in three categories of losses on ignition A, B and C by mass. The water-binder ratio, the air-entrainment and the workability of mixtures were maintained constant at 0.38, 4,5% and 150 mm respectively.Prior scaling causes a decrease in abrasion resistance of fly ash concretes. In addition, both quantitative and qualitative fly ash parameters and compressive strength have an influence on abrasion damage.

Application of Sulfoaluminate Cement for Solidification/Stabilization of Fly Ash from Municipal Solid Waste Incinerators

2012 ◽  
Vol 178-181 ◽  
pp. 795-798 ◽  
Author(s):  
Qi Na Sun ◽  
Jing Miao Li ◽  
Bao Quan Huo ◽  
Ji Bing Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
High Performance ◽  
Curing Time ◽  
Leaching Toxicity ◽  
Binder Ratio ◽  
Waste Incinerators ◽  
Water Binder Ratio

Sulfoaluminate cement (SAC) was utilized for the solidification/stabilization of fly ash from municipal solid waste (MSW) incinerators. The effects of fly ash amount and water/binder ratio were investigated on compressive strength and heavy metals leaching toxicity of solidified matrices at different curing times. The results showed that prolonged curing time, lower fly ash amount and water/binder ratio enhanced the compressive strength and decreased the leaching concentrations of Zn, Pb and Cu. For 28 days cured matrices with fly ash amount 50% and water/binder ratio 0.30, the compressive strength was 32.6 MPa and the leaching concentrations of Zn, Pb and Cu were 14.73, 0.75 and 0.43 mg/L respectively. The leaching concentrations of Zn, Pb and Cu met the demand of GB 5085.3-2007. SAC is proved to be effective for MSW incinerator fly ash solidification/stabilization and high performance matrices for disposal and reuse may be achieved with further formula optimization.

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