The Influence of High Temperatures and Time on the Material and Mechanical Properties of Cement Binder with Fly Ash

2018 ◽  
Vol 760 ◽  
pp. 119-126 ◽  
Author(s):  
Ondřej Zobal ◽  
Pavel Padevět
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Dynamic Modulus ◽  
Cement Pastes ◽  
Temperature Load ◽  
Cement Binder ◽  
Pozzolanic Properties ◽  
Non Destructive

The paper deals with the use of fly ash in cement and concrete. Fly ash, primarily waste material, can be used as a binder because of pozzolanic properties. This fact positively influences the economic and ecological part of the construction. At present, also in the context of higher fire protection requirements fly ash, it is mentioned as a possible material for the protection of structures from fire. The article presents and discusses the results of destructive tests of tensile strength and compressive strength and non-destructive verification of dynamic modulus of elasticity of cement pastes with fly ash after high temperature load. The test samples were almost six years old.

Effect of Fly Ash and Activator on Performance of Steam-Cured Concrete

2010 ◽  
Vol 113-116 ◽  
pp. 1013-1016 ◽  
Author(s):  
Zhi Min He ◽  
You Jun Xie ◽  
Guang Cheng Long ◽  
Jun Zhe Liu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Precast Concrete ◽  
Early Age ◽  
Flexure Strength ◽  
Concrete Elements ◽  
Chemical Activator

In precast concrete elements manufacturing, steam-cured concrete incorporating 30% fly ash encountered the problem of a too low demoulding compressive strength. To resolve it, this paper developed a new steam-cured concrete (AFSC) incorporating fly ash and a chemical activator. Experiments were conducted to investigate the mechanical properties of AFSC. The corresponding mechanism was also discussed by testing the microstructure of concrete. Results indicate that the demoulding compressive strength of AFSC can meet production requirements, and compressive and flexure strength of AFSC at later ages increase well. Compared with that of ordinary steam-cured concrete, AFSC has a higher tensile strength, and the capability of AFSC to resist cracks is enhanced remarkably. At an early age, addition of the chemical activator can distinctly accelerate the extent of hydration of the fly ash cement systems, and thus the microstructure of concrete becomes denser.

Research on the Basic Mechanical Properties of Fly Ash Fiber Reinforced Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 8-12
Author(s):  
Shu Shan Li ◽  
Ming Xiao Jia ◽  
Dan Ying Gao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Compressive Modulus ◽  
Fiber Reinforced Concrete ◽  
Cement Ratio ◽  
Influence Mechanism ◽  
Fiber Concrete ◽  
Early Strength

The basic mechanical properties of fly ash fiber concrete were tested. The influences to the compressive strength, splitting tensile strength and compressive modulus of elasticity of fiber concrete by water-cement ratio, dosage of fly ash and other factors were analyzed. The influence mechanism of fly ash to concrete is discussed. The results indicate that with the increase of the dosage of fly ash, the early strength of double-doped concrete is reduced, while the later strength of concrete was obviously increased.

scholarly journals Effect of Steel Fibers on Heat of Hydration and Mechanical Properties of Concrete Containing Fly Ash

2019 ◽  
Vol 38 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Sajid Mehmood ◽  
Faheem Butt
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Construction Projects ◽  
Heat Of Hydration ◽  
Steel Fibers ◽  
Modulus Of Rupture ◽  
Consistent Increase ◽  
Lower Heat

This study investigated the effects of steel fibers on the fresh and hardened properties, and heat of hydration of concrete containing FA (Fly Ash). A total of 192 samples were cast comprising cubes, cylinders, and prisms, for six concrete mixes with varying contents of steel fibers by volume and a fixed content of FA i.e. 15% by weight of cement. The semi adiabatic setup was used to monitor temperature rise due to the heat of hydration in the concrete mixes for fourteen days. The use of FA increased workability, and decreased early compressive strength, tensile strength and heat of hydration of concrete. However, an increase in the compressive strength of FA concrete was observed by the addition of steel fibers up to 0.9% whereas a consistent increase in the splitting tensile strength and modulus of rupture was observed with the addition of the steel fibers from 0.4-1.8%. Further the test results showed that increasing steel fibers content decrease the evolution of heat due to hydration. It was concluded that the FA concrete with steel fibers can be used in precast industry and mass construction projects due to the improved mechanical properties and lower heat of hydration.

scholarly journals Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete

2021 ◽  
Vol 30 (3) ◽  
pp. 464-476
Author(s):  
Haider Owaid ◽  
Haider Al-Baghdadi ◽  
Muna Al-Rubaye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Sodium Hydroxide ◽  
Wood Ash ◽  
Splitting Tensile Strength ◽  
Waste Paper ◽  
Geopolymer Concrete

Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.

The Effect of Micronized Waste Marble Powder as Partial Replacement for Cement on Resulting Mechanical Properties of Cement Pastes

2017 ◽  
Vol 1144 ◽  
pp. 54-58
Author(s):  
Zdeněk Prošek ◽  
Karel Šeps ◽  
Jaroslav Topič
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reference Material ◽  
Dynamic Modulus ◽  
Blended Cement ◽  
Partial Replacement ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Cement Pastes ◽  
Marble Powder

This article was focused on the influence of the micronized waste marble powder on mechanical properties of cement pastes. Resulting blended cement was composed of Portland cement CEM I 42.5 R and micronized marble powder with different percentage amounts (0 wt. %, 5 wt. %, 10 wt. % and 15 wt. %). Testing was carried at prismatic samples of dimension 40 × 40 × 160 mm. The investigated mechanical properties were dynamic modulus of elasticity, dynamic shear modulus, flexural strength and compressive strength for the 28 days old samples. The results obtained from these materials were compared with reference material.

Evaluation of Relations among Basic Mechanical Properties of Fly-Ash Concrete with Machine-Made Sand

2013 ◽  
Vol 438-439 ◽  
pp. 15-19
Author(s):  
Chun Jie Liu ◽  
Chun Yan Jia ◽  
Chang Yong Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Concrete Structures ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Fly Ash Concrete ◽  
Axial Compressive Strength

Although the machine-made sand was widely used for concrete in recent years in China, it was short of studies on the relations among the basic mechanical properties of fly-ash concrete with machine-made sand (MSFAC). However, these relations such as the compressive strength, the tensile strength and the elastic modulus with the cubic compressive strength (i.e. strength grade) are the basis of design for concrete structures. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that only the tensile strength of MSFAC can be safely forecasted by the same formula of ordinary concrete specified in current Chinese design code. When the strength grade is higher than C45, the axial compressive strength of MSFAC is largely forecasted by the formula of ordinary concrete. The elastic modulus of MSFAC is larger than that of ordinary concrete, which should be prospect by the formula in this paper. This work gives out some cautions for the proper use of the MSFAC in concrete structures.

scholarly journals Mechanical properties of concrete composed of sintered fly ash lightweight aggregate

2018 ◽  
Vol 195 ◽  
pp. 01008
Author(s):  
Puput Risdanareni ◽  
Januarti Jaya Ekaputri ◽  
Ike Maulidiyawati ◽  
Poppy Puspitasari
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Lightweight Aggregate ◽  
Effective Solution ◽  
Binding Agent ◽  
Split Tensile Strength ◽  
Bonded Method

This paper investigates the effect of sintered fly ash lightweight aggregate as coarse aggregate substitution on the mechanical properties of concrete. The lightweight aggregate (LWA) was produced using the cold bonded method and then sintered at a temperature of 900°C. An alkaliactivated system was applied as a binding agent of the LWA. Fly ash was used as precursor while sodium hydroxide and sodium silicate were employed as alkali activators. Three variations of the LWA dosage were performed, which were 0%, 50%, and 100 % of the volume of coarse aggregate in the concrete mixture. The mechanical properties of the concrete investigated in this research are the compressive strength and split tensile strength. The result showed that the mechanical properties of the concrete slightly decrease along with the increased dosage of the LWA in the mixture. However, employing sintered fly ash the LWA is proven as an effective solution in reducing the concrete density without sacrificing its strength.

scholarly journals A Comprehensive Study on the Factors Affecting the Workability and Mechanical Properties of Ambient Cured Fly Ash and Slag Based Geopolymer Concrete

2021 ◽  
Vol 11 (18) ◽  
pp. 8722
Author(s):  
Rana Muhammad Waqas ◽  
Faheem Butt ◽  
Xulong Zhu ◽  
Tianshui Jiang ◽  
Rana Faisal Tufail
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Geopolymer Concrete ◽  
Factors Affecting ◽  
Naoh Solution ◽  
New Material ◽  
Comprehensive Study ◽  
Slag Content

Geopolymer concrete (GPC), also known as an earth friendly concrete, has been under continuous study due to its environmental benefits and potential as a sustainable alternative to conventional concrete construction. However, there is still a lack of comprehensive studies focusing on the influence of all the design mix variables on the fresh and strength properties of GPC. GPC is still a relatively new material in terms of field application and has yet to secure international acceptance as a construction material. Therefore, it is important that comprehensive studies be carried out to collect more reliable information to expand this relatively new material technology to field and site applications. This research work aims to provide a comprehensive study on the factors affecting the fresh and hardened properties of ambient cured fly ash and slag based geopolymer concrete (FS-GPC). Industrial by-products, fly ash from thermal power plants, and ground granulated blast furnace slag from steel industries were utilized to produce ambient cured FS-GPC. A series of experiments were conducted to study the effect of various parameters, i.e., slag content (10%, 20%, 30%, and 50%), amount of alkaline activator solution (AAS) (35% and 40%), sodium silicate (SS) to sodium hydroxide (SH) ratio (SS/SH = 2.0, 2.5 and 3.0), sodium hydroxide concentration (10 M, 12 M, and 14 M) and addition of extra water on fresh and mechanical properties of FS-GPC. The workability of the fresh FS-GPC mixes was measured by the slump cone test. The mechanical properties of the mixes were evaluated by compressive strength, split tensile strength, flexure strength, and static modulus tests. The results revealed that workability of FS-GPC is greatly reduced by increasing slag content, molarity of NaOH solution, and SS/SH ratio. The compressive strength was improved with an increase in the molarity of NaOH solution and slag content and a decrease in AAS content from 40% to 35%. However, the influence of SS/SH ratio on mechanical properties of FS-GPC has a varying effect. The addition of extra water to enhance the workability of GPC matrix caused a decrease in the compressive strength. The validity of the equations suggested by previous studies to estimate the tensile and flexural strength and elastic modulus of FS-GPC mixes were also evaluated. Based on the test results of this study, empirical equations are proposed to predict the splitting tensile strength, flexural strength, and elastic modulus of ambient cured FS-GPC. The optimal mixtures of FS-GPC in terms of workability and mechanical properties were also proposed for the field applications.

Changes of the Properties of Cement Paste with Fly Ash Exposed to the High Temperature

2016 ◽  
Vol 677 ◽  
pp. 138-143
Author(s):  
Romana Lovichová ◽  
Pavel Padevět ◽  
Jindřich Fornůsek
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Cement Paste ◽  
Material Properties ◽  
Bound Water ◽  
Material Structure ◽  
Cement Pastes ◽  
Strength In Bending

This paper describes influence of exposure to high temperatures on material properties of cement paste with addition of fly ash. The properties of cement pastes are significant to the assumption behaviour of concrete and concrete structures. In the cement paste containing fly ash, the effect of high temperature up to 600 ° C causes the changes of content in physically bound water and the change in the material structure. The results of research indicate changes that are reflected in the material properties of the cement paste as compressive strength, tensile strength in bending.

Effect of Fluidity of Cement Mortar and Dispersion of Basalt Fibers on Mechanical Properties of BFRC Composites

2013 ◽  
Vol 671-674 ◽  
pp. 1869-1872 ◽  
Author(s):  
Wen Min He ◽  
Shuan Fa Chen ◽  
Chuang Wang ◽  
Xue Gang Zhang ◽  
Rui Xiong
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Cement Mortar ◽  
Basalt Fiber ◽  
Cement Matrix ◽  
Basalt Fibers ◽  
Dispersion Degree ◽  
Actual Effectiveness

Basalt fiber (BF) has a lot of advantageous properties. The actual effectiveness of the fiber depends greatly on their dispersion degree in the composites. With the help of ultrasonic wave and a dispersant carboxymethyl cellulose (CMC), the even dispersion of short basalt fibers in water is realized. The fluidity of the basalt fiber cement mortar becomes less as the fiber content increasing. When the fluidity of mortar of BFRC is greater than 170mm, the even dispersion of short basalt fibers in BFRC can be realized. Fly ash can effectively improve the fluidity of BFRC and the density of cement matrix. When the amount of fly ash replaces the cement less than 25% by weight, it can improve both the compressive strength and tensile strength at age of 28 days.

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