DOI : 10.17577/IJERTV2IS4492
- Open Access
- Total Downloads : 886
- Authors : A. Aielstein Rozario, Dr.C.Freeda Christy, M.Hannah Angelin
- Paper ID : IJERTV2IS4492
- Volume & Issue : Volume 02, Issue 04 (April 2013)
- Published (First Online): 16-04-2013
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Experimental Studies on Effects of Sulphate Resistance on Self-Curing Concrete
A.Aielstein Rozario*, Dr.C.Freeda Christy**, M.Hannah Angelin***
*School of Civil Engineering, Karunya University, CBE-114
**School of Civil Engineering, Karunya University, CBE- 114.
***Department of Civil Engineering, Coimbatore Institute of Technology, CBE- 014.
Abstract
This paper presents a detailed experimental study on sulphate attack measurement on self curing concrete at ages 28 days, and 56 days. The main investigation in this study is variation of water soluble polymer dosage of 0.05% and 0.1%. The concrete produced by the addition of fly ash as a partial replacement of cement. The percentage of weight loss and of concrete was studied. The test result indicates that use of water soluble polymers in concrete has improved performance of concrete.
Key words: Sulphate attack, Self-curing, PEG, Fly ash.
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Introduction
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Introduction to self curing
The major objective of the present invention is to provide a method for self-curing concrete. Adding water soluble polymers into concrete while mixing is called as self curing concrete. The self-curing agent can absorb moisture from atmosphere and then release into concrete, that concrete which is self- cured without any need of external curing after placing of concrete. So, the evaporation of water after removal of formwork can be minimized, and the
degree of hydration of cement is improved without external curing, and the compressive strength will be enhanced together with reduced shrinkage arising from evaporation of water, and make the concrete ideal for placing without any external curing. In this paper we deals with the effects of sulphate attack on self curing concrete.
There are several tests are available to find out the durability of concrete. Here, the Sulphate resistance test was done, the amount of soluble sulfates present in the material is a vital factor in determining the potential for sulfate attack on concrete. It depends on the penetration in the concrete specimen.
The end result of sulphate attack can be excessive expansion, delamination, cracking, and loss of strength. So the concrete should have the ability to resist the penetration of sulphate component to become a durable concrete. The objective of this work was to evaluate the behavior of self curing concrete when exposed to sulphate. The deterioration of concrete (weight loss) was evaluated.
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Experimental Part
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Materials Used
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Cement:
Ordinary Portland cement (53grade) was used in this study.
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Fly ash:
Fly ash is the best known and one of the most commonly used pozzolans. Class F is generally low in lime, usually under 5 per cent and contains of silica, alumina and iron (greater than 70 percent) than class C fly ash. Fly ash from Mettur Thermal power plant was used. It improves the cement paste microstructure because of production of C-S-H, and it is reactive, but at a much slower rate.
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Fine Aggregate:
Clean and dry river sand available locally was used as fine aggregate. IS 4.75 mm sieve was used.
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Coarse Aggregate:
20 mm aggregate was used as coarse aggregate.
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Water:
For the casting work and for the curing of specimens were done with the potable well and bore water at locally presented As per IS 456 -2000.
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Poly Ethylene Glycol (PEG):
PEG-400 Molecular weight was used as a self curing agent.
2.2 Test procedure:
The concrete mix were mixed and presented using a tilting drum mixer. The workability of self curing concrete was measured using the slump cone method. The workability of concrete mixes was comparable with slump ranging from 100 mm. The mix design is as per IS 10262:2000. The cube size of 100mm x 100
mm was taken for this test. The concrete mix design is for different grades like M20, M30, M40 and M50. The percentage of fly ash replacements are 10%, 15%, 20%, 25% used. The percentage of PEG dosages 0.05% and 0.1% are used for all grades of concrete with different replacements of fly ash.
2.2.1 Sulphate attack on concretes
The sulphate attack testing procedure was conducted by immersing concrete specimens after the specified initial curing in a water tank contacting 5% sodium sulphate and 5% magnesium sulphate separately for 28, and 56 days respectively. This type of testing represents an accelerated testing procedure, which indicates the performance of particular concrete mixes to sulphate attack on concrete. The sulphate solution was replaced whenever the pH value is exceeding 9.5. The percentage of sulphate attack was evaluated by measuring the weight losses of the specimens were conducted at 28, and 56 days respectively.
Formula used:
% of weight loss = [(Final weight – Initial weight)/ Initial weight] x 100
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Results and Discussion
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Sulphate Resistance Test:
Sulphate attack on ordinary Portland cement matrix is generally characterized by sulphate ions with products of cement hydration will cause expansion, cracks and spalling as well as loss of mass and strength.Various studies to minimize the attack and prolong the service life of concrete structures exposed to sulphate environments have been carried out. By the visual examination it is clear that the specimen subjected to sulphate attack behaves very differently and also degree of deterioration is high.
Tabe-1: Percentage of weight loss at 28th and 56th day for different grades:
Sl.No
GRADE OF CONCRETE
% OF WEIGHT LOSS AT 28TH DAY
% OF WEIGHT LOSS AT 56TH DAY
01
M20
0.8
2.70
02
M30
0.39
1.87
03
M40
0.79
1.46
04
M50
0.77
0.72
Tabe-2: Percentage of weight loss at 28th and 56th day for different grades with the replacement of fly ash:
Sl. No
GRADE OF CONCRETE
% OF FLY REPLACEMENT
% OF WEIGHT LOSS AT 28TH DAY
% OF WEIGHT LOSS AT 56TH DAY
01
M20
10%
3.38
3.47
15%
3.20
2.82
20%
3.10
2.64
25%
2.35
2.0
02
M30
10%
2.26
1.97
15%
2.04
1.85
20%
1.58
1.851
25%
1.56
1.56
03
M40
10%
0.793
1.55
15%
0.790
1.45
20%
0.780
1.15
25%
0.781
1.11
04
M50
10%
0.781
1.098
15%
0.76
0.2
20%
0.386
0.40
25%
0.384
0.378
Tabe-3: percentage of weight loss at 28th and 56th day for different grades with replacement of fly ash and different dosages of PEG:
Sl.No
GRADE OF CONCRETE
% OF FLY ASH
PEG DOSAGES
% OF WEIGHT LOSSAT 28TH DAY
% OF WEIGHT LOSS AT 56TH DAY
01
M20
10%
0.05%
6.45
6.42
0.1%
3.77
4.23
15%
0.05%
2.60
3.71
0.1%
2.50
2.85
20%
0.05%
2.12
2.81
0.1%
2.0
2.72
25%
0.05%
1.88
2.42
0.1%
1.55
2.33
02
M30
10%
0.05%
1.48
2.32
0.1%
1.29
2.25
15%
0.05%
1.19
1.93
0.1%
1.08
1.88
20%
0.05%
0.92
1.82
0.1%
0.84
1.67
25%
0.05%
0.79
1.56
0.1%
0.78
1.54
03
M40
10%
0.05%
0.766
1.47
0.1%
0.763
1.40
15%
0.05%
0.756
1.25
0.1%
0.754
1.22
20%
0.05%
0.749
1.22
0.1%
0.746
1.20
25%
0.05%
0.740
1.18
0.1%
0.729
1.14
04
M50
10%
0.05%
0.740
1.140
0.1%
0.40
1.132
15%
0.05%
0.39
1.11
0.1%
0.38
1.10
20%
0.05%
0.386
0.93
0.1%
0.3819
0.78
25%
0.05%
0.3816
0.72
0.1%
0.371
0.36
Fig-1: The container contains Na2So4 solution Fig-2: The cubes were immersed in the
Na2So4 solution
Fig-3: The deteriorated concrete specimen Fig-4: The concrete specimens are cured in On the 3rd day room temperature
% OF WEIGHT LOSSFOR M20 GRADE CONCRETE
7 6.64.542
6
5
4
3
2
1
% OF WEIGHT LOSSFOR M20 GRADE CONCRETE
7 6.64.542
6
5
4
3
2
1
0
0
PERCENTAPGE RPEPLACEMPENTSPOF FLY ASPH WIPTH DIFFERPENT DP OSAGES OF PEG
PERCENTAPGE RPEPLACEMPENTSPOF FLY ASPH WIPTH DIFFERPENT DP OSAGES OF PEG
4.23
4.23
3.71
3.71
3.47
3.47
3.1
3.1
2.82 2.81
2.82 2.81
2.72
2.72
2.7 2.64
2.7 2.64
2.42
2.42
2.33 2.32
2.33 2.32
28th Day
56th Day
28th Day
56th Day
0% 10% 10% 10%
FA FA
0% 10% 10% 10%
FA FA
FA
FA
15%
FA
15%
FA
15% 15%
15% 15%
FA
FA
FA
FA
20%
FA
20%
FA
20% 20%
20% 20%
FA
FA
FA
FA
25%
FA
25%
FA
25% 25%
25% 25%
FA
FA
FA
FA
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
% OF WEIGHT LOSS
% OF WEIGHT LOSS
Graph-1: Percentage of weight loss at 28th and 56th day for M20 grade with replacement of fly ash and different dosages of PEG
2.5
% OF WEIGHT LOSS
% OF WEIGHT LOSS
2
2.25
% OF WEIGHT LOSS FOR M30 GRADE CONCRETE
1.82
1.82
2 1.97 1.93 1.87 1.88 1.851 1.85
1.56
1.5
1.55 1.48
1.029
1.19
1.08
1.67
1.56 1.56 1.55
1
0.5
0.92
0.84
0.8
0.793
0.79
0.79
0.79
28TH DAY
56TH DAY
0
0% 10% FA
10% FA
10% FA
15% FA
15% FA
15% FA
20% FA
20% FA
20% FA
25% FA
25% FA
25% FA
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
0.05% 0.1%
P P P P P P P P
PERCENTAGE OF FLY ASH WITH DIFFERENT DOSAGE OG PEG
Graph-2: Percentage of weight loss at 28th and 56th day for M30 grade with replacement of fly ash and different dosages of PEG
% OF WEIGHT LOSS FOR M40 GRADE CONCRETE
% OF WEIGHT LOSS FOR M40 GRADE CONCRETE
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1.54
1.47 1.46 1.47 1.45
1.4
1.25
1.22 1.22
1.2 1.18
1.15 1.14
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1.54
1.47 1.46 1.47 1.45
1.4
1.25
1.22 1.22
1.2 1.18
1.15 1.14
0.05% 0.1% 0.05% 0.1% 0.05% 0.1% 0.05% 0.1%
P P P P P P P P
PERCENTAGE OF FLY ASH WITH DIFFERENT DOSAGE OF PEG
0.05% 0.1% 0.05% 0.1% 0.05% 0.1% 0.05% 0.1%
P P P P P P P P
PERCENTAGE OF FLY ASH WITH DIFFERENT DOSAGE OF PEG
0.781 0.781 0.78 0.78 0.77 0.766 0.76
0.781 0.781 0.78 0.78 0.77 0.766 0.76
0.76 0.763 0.756 0.754 0.749 0.746
0.76 0.763 0.756 0.754 0.749 0.746
28th Day
56th Day
28th Day
56th Day
0% 10% 10%
FA FA
0% 10% 10%
FA FA
10%
FA
10%
FA
15% 15% 15% 20% 20% 20% 25% 25% 25%
15% 15% 15% 20% 20% 20% 25% 25% 25%
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
FA
1
1
0.93
0.93
0.8
0.8
0.74 0.729 0.74
0.74 0.729 0.74
0.78
0.78
0.72 0.72 0.72
0.72 0.72 0.72
0.6
0.6
0.4 0.39
0.4 0.39
0.39 0.386 0.386 0.3840.38190.391600.4.380.03.73871
0.39 0.386 0.386 0.3840.38190.391600.4.380.03.73871
% OF WEIGHT LOSS
% OF WEIGHT LOSS
% OF WEIGHT LOSS
% OF WEIGHT LOSS
Graph-3: Percentage of weight loss at 28th and 56th day for M40 grade with replacement of fly ash and different dosages of PEG
% OF WEIGHT LOSS FOR M50 GRADE CONCRETE
% OF WEIGHT LOSS FOR M50 GRADE CONCRETE
1.2
1.14 1.132 1.11
1.11 1.1 1.098
1.2
1.14 1.132 1.11
1.11 1.1 1.098
0
0
0% 10% 10% 10% 15% 15% 15% 20% 20% 20% 25% 25% 25%
FA FA FA FA FA FA FA FA FA FA FA FA 0.05% 0.1% 0.05% 0.1% 0.05% 0.1% 0.05% 0.1%
P P P P P P P P
PERCENTAGE OF FLY ASH WITH DIFFERENT DOSAGES OF PEG
0% 10% 10% 10% 15% 15% 15% 20% 20% 20% 25% 25% 25%
FA FA FA FA FA FA FA FA FA FA FA FA 0.05% 0.1% 0.05% 0.1% 0.05% 0.1% 0.05% 0.1%
P P P P P P P P
PERCENTAGE OF FLY ASH WITH DIFFERENT DOSAGES OF PEG
0.4
0.4
0.2
0.2
28th Day
56th Day
28th Day
56th Day
Graph-4: Percentage of weight loss at 28th and 56th day for M50 grade with replacement of fly ash and different dosages of PEG
-
-
Results and Discussion:
The permeability of concrete decreases with increase in the replacement of fly ash with cement and in addition of P.E.G dosages.
So the penetration of chemicals is decreased with the addition of PEG and the concrete is safe against sulphates.
The percentage of weight loss of the concrete specimens are also decreased for every grades of concrete.
From the results, we know that the self- curing concrete has the ability to resist the sulphates present in the soils and in the sea waters. It is very economical also, So it can be adoptable for the constructions.
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References:
-
Aiminxu Test methods for sulphate resistance of concrete and mechanism of sulphate attack September 1998.
-
Ian Longworth Sulfate damage to concrete floors on sulfate-bearing hardcore February 2008.
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QCL Group sulphate attack and chloride ion penetration: their role in concrete durability March 99.
-
Corral-Higuera R, Arredondo-Rea S.P, Neri-Flores M.A., Gómez- Soberón J.M., Almeraya Calderón F, Castorena-González J.H, Almaral- Sánchez J.L Sulfate Attack and Reinforcement Corrosion in Concrete with Recycled Concrete Aggregates and Supplementary Cementing Materials 1 March 2011.