Influence of Variable Temperature Curing on Mechanical Properties of Fly Ash Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 178-181
Author(s):  
Ya Ding Zhao ◽  
Xue Ying Li ◽  
Ling Chao Kong ◽  
Wei Du

Under variable temperature curing conditions(30 oC ~70 oC), concrete with fly ash whose compressive strength, flexural strength, and dynamic elastic modulus are better than ones without fly ash.Compared with constant temperature 20oC, 50 oC and 70 oC, variable temperature curing(VTC) is benefit for the improvement of mechanical properties of 30% fly ash concrete, but which is no advantage to improve performance of 50% fly ash concrete.

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.


2013 ◽  
Vol 438-439 ◽  
pp. 15-19
Author(s):  
Chun Jie Liu ◽  
Chun Yan Jia ◽  
Chang Yong Li

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.


2013 ◽  
Vol 800 ◽  
pp. 361-364
Author(s):  
Lin Chun Zhang

A series of experiments were carried out to investigate the effect of wollastonite and fly ash combination on the compressive strength, flexural strength, modulus of elasticity, coming off amount, loss percentage of dynamic elastic modulus as well as surface scaling of concrete. The studies show that the effect of mixing wollastonite and fly ash can reach excellent mechanical and durability performance. The effect of mixing wollastonite and fly ash improve the mechanical and durability is better than mixing fly ash alone. The concrete mixes containing wollastonite and fly ash indicated that wollastonite addition 15% was found advantageous in improving concrete quality.


2008 ◽  
Vol 59 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Jenica Paceagiu ◽  
Maria Georgescu

The paper brings information on the influence of curing conditions such as humidity, variable temperature and chemical solutions, on the compressive strength and weight variation of the magnesia phosphate binding materials, obtained from magnesite, mono-ammonia phosphate, borax and sand having a granulation ranging between 0.1-1 mm, with or without fly ash addition. The XRD and SEM�EDX analysis were made for obtaining information concerning the reaction products formed in phosphate magnesia binding materials cured in conditions of variable humidity.


2013 ◽  
Vol 539 ◽  
pp. 70-74
Author(s):  
Yun Fang Meng ◽  
Yong Qi Wei ◽  
De Zhi Wang ◽  
Ke Gao

The effects of rubber powder (RP) and fly ash (FA) with various dosages on flexural and compressive strength of recycled mortars were investigated. Experimental results indicated that the single addition of 4 wt.% RP helped to improve the flexural strength of recycled mortars, but the compound addition of RP and FA in recycled mortars reduced the strength, whatever the compressive or flexural strength; the mechanical properties of recycled mortars with or without RP or FA were better than that of ordinary mortars.


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.


2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.


2011 ◽  
Vol 418-420 ◽  
pp. 441-444 ◽  
Author(s):  
Feng Lan Li ◽  
Yan Zeng ◽  
Chang Yong Li

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. 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 the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.


2014 ◽  
Vol 660 ◽  
pp. 312-316
Author(s):  
Mochamad Solikin ◽  
Budi Setiawan

This paper reports an investigation on mechanical properties of high volume fly ash (HVFA) concrete produced using different types of mixing water i.e. tap water and saturated lime water. The mechanical properties of ordinary Portland cement concrete are also investigated as control tests. The concrete were tested for their compressive strength, flexural strength and splitting tensile strength at the curing ages of 56 days. The results showed that strength development of high volume fly ash concrete up to 56 days is lower than ordinary portal cement. In addition, the flexural strength and splitting strength of concrete are lower than ordinary Portland cement. Moreover, the use of saturated lime water as mixing water reduces the mechanical properties of class C high volume fly ash concrete.


2021 ◽  
Vol 7 ◽  
Author(s):  
D. Ali ◽  
U. Sharma ◽  
R. Singh ◽  
L. P. Singh

In the present study, the mechanical and durability properties of silica nanoparticle (SNP)-incorporated fly ash (FA) concrete mix were examined after 365 days of exposure. The dosages of FA replaced by cement in the present study were 30%, 40%, and 50%, while 3% SNPs were added by the weight of cement in the FA incorporated mix. For a comparison of SNPs with silica fume (SF), 6% SF was added (by the weight of cement) and entire casting was performed at a constant water to binder (w/b) ratio of 0.29. The present work is the extension of a previous study wherein durability properties of the same mixes were reported for up to 180 days of exposure. Compressive strength results show that in the presence of SNPs, the enhancement in compressive strength was in the range of 10–14%, while, in presence of SF, 8–10% of the enhancement was observed as compared to control. However, exposed samples in a carbonation environment showed that the compressive strength of the control and SF incorporated mix increased, while SNP-incorporated samples showed negligible enhancement. Further, sulphate exposed mix show that compressive strength decreases, however, the SNP-incorporated mix showed the lowest reduction compared to other mixes. Therefore, the study shows that the SNP-incorporated mix has higher mechanical properties and more durability compared to other mixes in a severe environment.


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