Experimental Study on Activity of Fly Ash Replacing Cement in Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 46-49
Author(s):  
Chang Yong Li ◽  
Long Jiang ◽  
Yang Liu ◽  
Zhi Ming Xu
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Cement Ratio ◽  
Active Factor ◽  
Water Cement Ratio ◽  
Binder Ratio ◽  
Mass Factor ◽  
Compressive And Flexural Strengths ◽  
Water Binder Ratio

The test and contrast mortars were made by changing water-binder (water-cement) ratio from 0.4 to 0.6, fly ash replacing rate from 10% to 30% and over-mass factor of fly ash from 1.3 to 1.7 with different methods of equal-replacing and over-mass replacing cement by fly ash. The variation of compressive and flexural strengths of mortar with water-binder ratio and admixing amount of fly ash are analyzed based on the test strengths. The formulas for calculating active factor of fly ash are proposed, and the regularity of active factor with the change of water-binder ratio and admixing amount of fly ash are given out.

Environmental Sustainability and Engineering Performance of Self-Compacting Mortar Incorporating Fly Ashes

2012 ◽  
Vol 253-255 ◽  
pp. 559-563 ◽  
Author(s):  
Putri Zulaiha Razi ◽  
Hashim Abdul Razak
Keyword(s):  
Fly Ash ◽  
Environmental Sustainability ◽  
Cement Content ◽  
Co2 Reduction ◽  
Fly Ashes ◽  
Cement Ratio ◽  
Low Co2 ◽  
Slump Flow ◽  
Binder Ratio ◽  
Water Binder Ratio

This paper investigated the effect of fly-ash on environmental sustainability and engineering performance of mortar. Samples of mortar were prepared with different dosage of superplasticizer to gives three ranges of workability that is normal slump flow, high slump flow and self-compacting flow. Cement content of 550 kg/m³, water/binder ratio of 0.35, binder/cement ratio of 2.00 and fly ash replacement 10%,20%, 40%, and 60% were adopted for the mix proportion.The relationship to look into are the potential of CO2 reduction in the mortar mixes while cement content were replace by fly ash. Results showed that self-compacting mixes with 20 % replacement by fly ash provides an increase in 28 day strength, enhancing the durability with low % of water absorption and reducing the environmental impact with low CO2 footprint. This gives it the best balance of durability and environmental sustainability impact of the mixes.

Experimental Study on Thermal Conductivity of Road Concrete

2012 ◽  
Vol 178-181 ◽  
pp. 1573-1576
Author(s):  
Yan Cong Zhang ◽  
Ling Ling Gao ◽  
Jun Min Shen
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Gas Content ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Air Content ◽  
Main Factor

In order to analyses affection to thermal conductivity from various factors, such as: coarse aggregate, mortar ratio, sand ratio, water cement ratio, fly ash and air content, thermal conductivity of a series of concrete specimens were determined based on thermal conductivity meter. The results showed that: coarse aggregate, mortar ratio and gas content is the main factor affecting concrete thermal conductivity. Meanwhile, water-cement ratio, sand ratio and fly ash had few effects on the thermal conductivity. In addition, a certain formula to predict thermal conductivity of concrete was proposed.

scholarly journals Effectiveness of Locally Available Superplasticizers on the Workability and Strength of Concrete

2018 ◽  
Vol 4 (12) ◽  
pp. 2919 ◽  
Author(s):  
Ashfaque Ahmed Jhatial ◽  
Samiullah Sohu ◽  
Muhammad Tahir Lakhiar ◽  
Jam Shahzaib ◽  
Ahsan Ali Buriro
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Water Content ◽  
Research Work ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimum Dosage ◽  
Chemical Admixtures ◽  
Compressive And Flexural Strengths

Though superplasticizers (SP) are well-known chemical admixtures which are added into concrete to enhance the workability and achieve higher strength while reducing the water content. But the rapid increase in different SP in Pakistan has created confusion on the effectiveness of SP. This experimental study was carried out to study the effect of locally available SP on the workability and compressive strength of M15 grade concrete. Three different SP were utilized, with dosage ranging from 0.5% to 2.5% with an increment of 0.5%. The water-cement ratio remained constant at 0.5 for all samples. Based upon the results, all three SP increased the workability as well as strength of concrete. The optimum dosage was determined to be 1.5% to 2.00% for all three SPs used in this research work. BASF 561 was determined to be more effective, as it achieved the maximum workability as well as compressive and flexural strengths.

Assessment of Hydration Degree of Cement in the Fly Ash-Cement Pastes Based on the Calcium Hydroxide Content

2014 ◽  
Vol 875-877 ◽  
pp. 177-182 ◽  
Author(s):  
Xiang Li ◽  
Hua Quan Yang ◽  
Ming Xia Li
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Cement Hydration ◽  
Ash Content ◽  
Content Increase ◽  
Hydration Degree ◽  
Equilibrium Calculation ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio

The hydration degree of fly ash and the calcium hydroxide (CH) content were measured. Combined with the equilibrium calculation of cement hydration, a new method for assessment of the hydration degree of cement in the fly ash-cement (FC) pastes based on the CH content was developed. The results reveal that as the fly ash content increase, the hydration degree of fly ash and the CH content decrease gradually; at the same time, the hydration degree of cement increase. The hydration degree of cement in the FC pastes containing a high content of fly ash (more than 35%) at 360 days is as high as 80%, even some of which hydrates nearly completely. The effect of water-cement ratio to the hydration degree of cement in the FC pastes is far less distinct than that of the content of fly ash.

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 Compressive Strength and Flexural Strength of Combined Aggregate Concrete

2014 ◽  
Vol 1065-1069 ◽  
pp. 1899-1902
Author(s):  
Yan Kun Zhang ◽  
Yu Cheng Wang ◽  
Xiao Long Wu
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Test Method ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Comprehensive Test

In this article, the flexural strength of combined aggregate concrete with four kinds of water-cement ratio (0.3,0.35.0.4, 0.45), and six ceramsite replace rate (0%, 20%, 40%, 60%, 80%, 60%) are studied with comprehensive test method. Experiment shows that the ceramsite replace rate of combined aggregate has greater influence on the flexural strength than the water-cement ratio. The flexural strength increases with the increasing of compressive strength, and the formula of the flexural strength and compressive strength of combined aggregate concrete is given.

Sign in / Sign up

Export Citation Format

Share Document