Mechanical Characteristics of Concrete Exposed to External Flexural Load, De-Icing Salt and Freeze-Thaw Cycles

2011 ◽  
Vol 250-253 ◽  
pp. 33-39
Author(s):  
Xiao Lu Yuan ◽  
Bei Xing Li ◽  
Shang Chuan Zhao ◽  
Shi Hua Zhou
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Ordinary Portland Cement ◽  
Mechanical Characteristics ◽  
Concrete Strength ◽  
Mineral Admixtures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw

This paper investigates mechanical characteristics of concrete exposed to external flexural load, de-icing salt and freeze-thaw cycles. Concrete specimens made with ordinary Portland cement or ordinary Portland cement incorporating fly ash with the replacement of 10% or 20%, or 0.7/10000 air-entraining agent and 20% fly ash, or ground blast furnace slag with the replacement of 15% or 30%, were made and exposed to flexural load, freeze-thaw and de-icing salt environment. Mechanical properties of concrete including compressive strength and flexural strength were measured. Phase composition of samples was determined by means of x-ray diffraction (XRD). Results indicate that increasing flexural stress ratios reduced compressive strength and flexural strength of concrete, and presented higher improvement of mineral admixtures in concrete strength. Incorporation of mineral admixtures and air-entraining agent decreased the loss of concrete strength. X-ray diffraction analysis showed the presence of abundant calcium chloroaluminate and ettringite in paste samples.

scholarly journals Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash

2018 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Longhui Wang ◽  
Yafeng Gong
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pervious Concrete ◽  
Early Age ◽  
Pavement Materials ◽  
Freeze Thaw ◽  
Replacement Method ◽  
Porosity And Permeability ◽  
Volume Method

Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.

scholarly journals Influence of Mineral Admixtures on Corrosion Inhibition Effect of Nitrites

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Mengna Yang ◽  
Junzhe Liu ◽  
Hui Wang ◽  
Yushun Li ◽  
Yanhua Dai ◽  
...  
Keyword(s):  
Fly Ash ◽  
Corrosion Inhibition ◽  
Ion Concentration ◽  
Mineral Admixtures ◽  
X Ray Diffraction ◽  
Nitrite Ion ◽  
X Ray ◽  
Inhibition Effect ◽  
Diffraction Patterns ◽  
Micro Analysis

Chemical quantitative analysis of effective anticorrosion component and micro-analysis of hydration products of fly ash and slag on the influence of the nitrites corrosion inhibition was studied by the free nitrite ion concentration and X-ray diffraction pattern. The free nitrite ion concentration was used to describe the corrosion inhibition effect of nitrites. And the X-ray diffraction patterns were used to analyze the adsorption properties. The research results show that fly ash and slag were beneficial for improving the corrosion inhibition effect of nitrites. Cement-based materials with slag at low content presented high free nitrite ion concentration, but the addition of low content of fly ash harmed the corrosion inhibition effect of nitrites. The specimens incorporated with both fly ash and slag can reach the highest free nitrite ion concentration when the compounding proportion was 1:1. It was concluded that the extent of mineral admixtures of the corrosion inhibition effect of nitrites was affected by its type and content.

scholarly journals Strength Characteristics of High Strength Concrete (HSC) with and without Coarse Aggregate

2019 ◽  
Vol 9 (2) ◽  
pp. 4701-4704
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Mechanical Characteristics ◽  
Coarse Aggregate ◽  
High Strength ◽  
Set Up

This paper aimed to investigate the mechanical characteristics of HSC of M60 concrete adding 25% of fly ash to cement and sand and percentage variations of silica fumes 0%,5% and 10% to cement with varying sizes of 10mm,6mm,2mm and powder of granite aggregate with w/c of 0.32. Specimens are tested for compressive strength using 10cm X 10cmX10cm cubes for 7,14,28 days flexural strength was determined by using 10cmX10cmX50cm beam specimens at 28 days and 15cm diameter and 30cm height cylinder specimens at 28 days using super plasticizers of conplast 430 as a water reducing agent. In this paper the experimental set up is made to study the mechanical properties of HSC with and without coarse aggregate with varying sizes as 10mm, 6mm, 2mm and powder. Similarly, the effect of silica fume on HSC by varying its percentages as 0%, 5% and 10% in the mix studied. For all mixes 25% extra fly ash has been added for cement and sand.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.

Influence of Wollastonite or Plant Fiber on Performance of Autoclaved Cement Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 692-695
Author(s):  
Tie Quan Ni ◽  
Li Zhang ◽  
Bing Yuan
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bending Strength ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Cement Concrete ◽  
Plant Fiber ◽  
X Ray ◽  
Strength Change ◽  
Chemical Composition Analysis

The influence of wollastonite or plant fiber on the property of autoclaved cement concrete is studied by chemical composition analysis, X-ray diffraction analysis, scanning electron microscopy and energy spectrum analysis. The results showed that the two fibers were benefit to bending strength of autoclaved cement concrete. The suitable content of wollastonite was about 15% of cement mass, and the increased amplitude of flexural strength was more than 30% and the compressive strength slightly increased for autoclaved cement concrete admixed wollastonite. The optimal content of plant fiber was about 1.5% of cement mass, the increased amplitude of the flexural strength was more than 20%, and the compressive strength change of autoclaved cement concrete was not significant for autoclaved cement concrete admixed plant fiber.

The Influence of Combined Admixture of Super-Fine Limestone Powder and Low-Quality Fly Ash on the Performance of Cement Mortar

2013 ◽  
Vol 652-654 ◽  
pp. 1181-1184
Author(s):  
Guo Qiang Xu ◽  
Zhi Guo You ◽  
Lin Gao ◽  
Dian Li Han
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Limestone Powder ◽  
Mineral Admixtures ◽  
Test Results ◽  
Maximum Compressive Strength

The influence of admixture of super-fine limestone powder and low-quality fly ash in different proportions on the fluidity and strength of cement mortar is studied. The test results show that the mortar fluidity increases with the increase of the super-fine limestone powder (the mixing amount of fly ash reduces), and the strength of cement mortar can improve when limestone powder and low-quality fly ash are combined admixed to a certain ratio. The maximum flexural strength of the 28d mortar is 9.8MPa and its maximum compressive strength is 42.2MPa, and at this time, the limestone powder accounts for 33.3% of the mineral admixtures. However, when the mixing amount of super-fine limestone powder is over a certain range, the strength of 28d cement mortar will reduce.

Magnesium Phosphate Cement with Large Volume of Fly Ash

2012 ◽  
Vol 174-177 ◽  
pp. 802-805 ◽  
Author(s):  
Zhu Ding ◽  
Bi Qin Dong ◽  
Feng Xing
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Large Volume ◽  
Sodium Phosphate ◽  
Cement Mortar ◽  
Cementitious Materials ◽  
X Ray Diffraction ◽  
Monoammonium Phosphate ◽  
Ammonia Gas ◽  
X Ray

The accumulation of fly ash leads to severe problems in ecological environments. Various ways to excite the activity of fly ash in Portland cement based cementitious materials have been carried out for many years. In the present study, effect of large volume of fly ash in phosphate cement was studied. Dead burned magnesia, two phosphates (monoammonium phosphate and monosodium phosphate), and fly ash were used. The fabricated cement mortar specimens with different fly ash dosages were cured for 28 days in the lab air. Compressive strength was determined in 1d, 3d, 7d and 28d respectively. It is showed the compressive strength reduced with increase of fly ash content and increased with the curing time. After cured 28 days, the compressive strength of cement mortar developed to14MPa, when 80% fly ash was used. The reaction product, Na2HPO4•17H2O was found by X-ray diffraction analysis in sodium phosphate based cement. No ammonia gas was emitted and large volume of fly ash can be used in cement prepared from sodium phosphate. It is a new environmentally friendly cement material.

scholarly journals The Filler Effect on Compressive Strength of Sulfur Concrete

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wenwei Lin ◽  
Fan Fei ◽  
Qunjie Li
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Fly Ash ◽  
Scanning Electron Microscope ◽  
Chemical Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compressive Performance ◽  
Bonding Mode ◽  
Scanning Electron

The sulfur concrete samples were prepared by the optimized process, which were mixed with cement, fly ash and slag, respectively. The influence of the type and content of filler on the compressive strength of sulfur concrete was studied. The phase and micromorphology of filler and sulfur mixture were characterized by X-ray diffraction and scanning electron microscope, and the bonding mode was studied. The results show: the cement filler has the best effect on the compressive performance of sulfur concrete,and the compressive strength is 87.2 MPa by adding cement filler with the same quality as sulfur; there is no chemical reaction between filler and sulfur, and the filler is physically bonded to sulfur matrix.

scholarly journals Effect of Elevated Temperature on Alkali Activated Slag and Fly Ash based Geopolymer Concrete

2020 ◽  
Vol 9 (4) ◽  
pp. 1241-1250
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Flexural Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Geopolymer Concrete ◽  
Base Materials ◽  
Activated Slag ◽  
Alkali Activated

Activated Slag (AAS) and Fly Ash (FA) based geopolymer concrete a new blended alkali-activated concrete that has been progressively studied over the past years because of its environmental benefits superior engineering properties. Geopolymer has many favorable characteristics in comparison to Ordinary Portland Cement. Many base materials could be utilized to make geopolymer with the convenient concentration of activator solution. In this study, the experimental program composed of two phases; phase on divided into four groups; Group one deliberated the effect of sodium hydroxide molarity and different curing condition on compressive strength. Group two studied the effect of alkali activated solution (NaOH and Na2SiO3) content on compressive strength and workability. The effect of sand replacement with slag on compressive strength and workability was explained in group three. Group four studied the effect of slag replacement with several base materials Fly Ash (FA), Ordinary Portland Cement (OPC), pulverized Red Brick (PRB), and Meta Kaolin (MK). Phase two contains three mixtures from phase one which had the highest compressive strength. For each mixture, the fresh concrete test was air content. In addition the hardened concrete tests were the compressive strength at 3, 7, 28, 90, 180, and 365 days, the flexural strength at 28, 90, and 365 days, and the young's modulus at 28, 90, and 365 days. Moreover; the three mixtures were exposed to elevated temperature at 100oC, 300oC, and 600oC to study the effect of elevated temperature on compressive and flexural strength.

scholarly journals Impact of Nanosilica in Ordinary Portland Cement Over Its Durability and Properties

2021 ◽  
Author(s):  
Gude Reddy Babu ◽  
Pala Gireesh Kumar ◽  
Nelluru Venkata Ramana ◽  
Bhumireddy Madhusudana Reddy
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Flexural Strength ◽  
Scanning Electron Microscope ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
X Ray Diffraction ◽  
Cement Strength ◽  
The Impact ◽  
Scanning Electron

The present examination illustrates the impact on the hardened and fresh cement mortar and cement with the inclusion of nanosilica of size 40 nm in various environmental conditions (UltraTech, India). It is quite notified that an elevation in compressive strength as well as flexural strength along with an improvisation in the performance and life span of cement mortar. The samples of M5 grade blended with a ninety percentage of concrete and remaining with nanosilica was identified to have a finer working elevation in as well as in standards when collated with the conventional cement mortar. The corollary of hardened and fresh cement, strength parameters were looked upon with the aid of XRD (X-ray Diffraction). Also, the SEM (Scanning Electron Microscope) test holds a predominant role in analysis.

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