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International Journal Of Advancement In Engineering Technology, Management and Applied Science (IJAETMAS)

ISSN: 2349-3224 || www.ijaetmas.com || Volume 04 - Issue 01 || January- 2017 || PP. 15-23

CONCRETE MADE FROM CERAMIC ELECTRICAL INSULATOR WASTE

YOUNUS ATest Engineer, Farm Machinery Testing Centre, KCAET, Tavanur, Kerala, India

Abstract— Concrete which contains waste products as aggregate is called ‘Green’ concrete. Concrete made with ceramic electrical insulator waste as coarse aggregate shows good workability, compressive, tensile and flexural strengths and modulus of elasticity. Further, study of its durability will ensure greater reliability in its usage.

Waste material produced by the sanitary ceramics industry can be reused as aggregate in structural concrete mixes, as well as to analyze the economic and environmental benefits of this reuse. Firstly, aggregates were classified in order to assess their suitability for concrete mixing. Once the necessary assays had been carried out, different mixes were produced by gradually substituting part of the natural coarse aggregate with the recycled ceramic material. These concrete mixes were tested to determine their structural properties and results show that we can be optimistic when considering use of this kind of waste material in structural concrete. Permeation characters are used widely to quantify durability properties of concrete. This is an experimental investigation on the permeation characteristics [volume of voids and water absorption, chloride penetration, and sorption] of concrete with ceramic electrical insulator waste coarse aggregate (hereafter it is called recycled aggregate concrete) of six different water–cement ratios in comparison with those of corresponding conventional concrete mixes From the results it has been observed that there is no significant change in the basic trend of permeation characteristics of this recycled aggregate concrete when compared to the conventional concrete.

Keywords— Concrete , ceramic, electrical insulator, Waste material,

INTRODUCTION

The main objective of the reuse of material is to minimize the impact of human activities on the environment and the planet. The use of alternative aggregate is a natural step towards solving part of the depletion of natural aggregate, and the alternative aggregate processed from waste materials would appear to be an even more sensible solution. The need to develop concrete with non-conventional aggregates rose due to environmental trends as well as economical reasons.

It has been estimated in a survey that about 30% of daily production goes as waste in a ceramic electrical insulator industry, which is not reused in any form at present and hence, piling up every day. There is pressure on the ceramic electrical insulator industries to find a solution for its disposal. However the ceramic electrical insulator waste is highly resistant to biological degradation forces. This waste is durable, hard and almost inert to normal chemicals. Clay minerals become highly reactive when they are incinerated at temperatures between 600-900°C and then ground to cement fineness. They are mainly formed by siliceous and aluminous compounds. The loss of water due to thermal treatments causes destruction of their crystalline structure, and they are converted into unstable amorphous state. If they are then mixed with calcium hydroxide and water, they undergo pozzolanic reaction and form compounds with enhanced strength and durability. Therefore, they have a potential to be used in mortar and concrete. In this seminar, a wide range of parameters of concrete containing waste ceramics as partial replacement of natural aggregate is presented.

The movement of gases, liquids and ions through concrete is called permeation. Different permeation processes for deleterious substances through concrete are diffusion, absorption and permeability. The permeation of water in concrete provides a path for the

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penetration of deleterious materials such as chloride and sulfate ions which can lead to corrosion of reinforcement in reinforced concrete structures. The durability of concrete can be assessed by the measurement of concrete permeation characteristics

Waste ceramic materials may become a cheaper but almost equivalent alternative to metakaolin or ground granulated blast furnace slag, fly ash and other materials as supplementary binder in concrete. The ceramic industry often produces calcined clays that result from burning illite-group clays which are commonly used in the production of red-clay ceramic products. A portion of these products (which amounts up to 2% depending on producer and country) is discarded as scrap, thus constitutes industrial waste. The residues of ceramic bricks and floor and roof tiles ground to a suitable fineness can though become active pozzolans [1-3]. So, they have a potential to be used in mortar and concrete. The measurements of properties of materials containing supplementary cementing materials are similarly as with many other cement based composites mostly concentrated on mechanical properties. This may not always be sufficient because superior mechanical properties are often not accompanied by comparably good resistance against water or salt penetration.

Fig.1.a. Ceramic electrical insulator Fig.1.b. Ceramic electrical insulator

waste materials

2. MATERIALS USED

Ceramic electrical insulator waste coarse aggregate

The ceramic electrical insulator waste (Fig. 2) is produced from the nearby ceramic electrical insulator industry and their surfaces are de-glazed manually by chisel and hammer. With the help of jaw crusher the de-glazed ceramic electrical insulator wastes are broken into 20 mm maximum size coarse aggregate.

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Crushed granite coarse aggregate

Crushed granite coarse aggregate of maximum size 20 mm is used in conventional concrete.

Fig.2. Ceramic electrical insulator waste coarse aggregate & Crushed granite course aggregate .

Other ingredients

Ordinary Portland cement 53Grade and river sand of specific gravity 2.67 and fineness modulus 2.62 and potable water are used in both ceramic electrical insulator waste coarse aggregate concrete and conventional concrete mixes.

MIX DESIGN

The mix design for the ceramic electrical insulator waste coarse aggregate concrete is based on absolute volume method. By conducting trial mixes and proportion of these mixes are adjusted to arrive at an optimum mix proportion, which is used throughout the entire investigation. The ceramic electrical insulator waste coarse aggregate concrete mixes are proportioned with six different water–cement ratios (0.35, 0.40, 0.45, 0.50, 0.55, and 0.60). The volume of water and coarse aggregate are kept constant while the volume of cement and sand is varied. In a similar manner, by following the absolute volume method .

WASTE FROM THE CERAMIC INDUSTRYTest specimens

For each mix, six cubes (100 mm) and six cylinders (100 mm ɸ and 200 mm




height) are cast. The specimens are cast in steel molds and compacted on a vibrating table. They are de- molded after 24 h, and cured under water at 27 ± 2 °C for 28 days. Cubes are used for testing of water absorption and volume of voids. The cylindrical specimens are cut into four equal pieces of thickness 50 mm using a circular cutting saw. Out of the four pieces the middle two pieces are used for sorption and chloride diffusion tests.

Saturated water absorption and volume of voidsThe saturated water absorption and the volume of voids of ceramic electrical

insulator waste coarse aggregate concrete and conventional concrete cube specimens are determined using the procedure given in ASTM C642-06. The cube specimen is dried in an oven at a temperature of 105 °C for 24 h. After removing the specimen from the oven, it is allowed to cool in dry air and weighed. The specimen is then immersed in water for 48 h and the saturated surface dry (SSD) weight of the specimen is measured. Then the specimen is immersed in water and boiled continuously for 5 h. It was taken out, cooled, surface moisture is removed by a towel and then the saturated surface dry (SSD) weight is measured. Finally the specimen is suspended by a wire and the apparent weight was measured in water. Percentage of water absorption is the ratio of the difference between the weight of SSD sample after immersion and the weight of oven dry sample to the weight of oven-dry sample. Volume of voids is the ratio of the difference between the weight of SSD sample after boiling and the weight of oven-dry sample to the difference between the weight of SSD sample after boiling and the apparent weight of sample in water.

Sorptivity

Sorptivity is a term used for water ingress into pores under unsaturated conditions due to capillary suction. The sorptivity values of ceramic electrical insulator waste coarse aggregate concrete and conventional concrete are determined by the measurement of water absorption by capillary rise. The specimens are 100 mm diameter and 50 mm thick concrete disc, saw-cut from the 100 mm X 200 mm cylinders. Each disc’s side surface is coated with an impermeable epoxy coating to prevent the absorption through side surface during the test

Fig.3 Experimental arrangement of sorptivity test

Then the specimens are oven dried at 105 ± 5 °C to constant weight. Initial weights are taken after cooling to atmospheric temperature. The specimens are kept in a water tray with small supports, as shown in Fig. 3. and the water level was maintained in such a way that only the bottom 3–5 mm of the specimens were submerged in water. At any time




t, the water absorbed through the bottom of the specimen is the difference between the initial weight and the weight at that time. These values can be used to determine the sorptivity S Where, I is the cumulative water absorption per unit area of inflow surface in g/mm2, t is elapsed time in minutes and S is the sorptivity of concrete. S can be obtained from a linear

regression of I versus t1/2 plot.

Chloride diffusionThe resistance to chloride penetration is one of the simplest measures to determine

the durability of concrete. Separate specimens of similar size were cut from the same cylinder for conducting RCPT. Test duration is 6hour.The RCP test is conducted on saturated and surface dry specimens. Experimental arrangement is shown in Fig.4.The specimens are placed in testing apparatus where one end of the specimen is exposed into a solution containing NaCl solution and other end in NaOH solution. There increase the rate of chloride penetration into specimen, thus speeding up the test. A constant 60V potential is applied across the specimen. Current across the specimen is measured at least every 30 minutes during 6hour test. As the chloride penetrate deeper into the concrete, it become more conductive and current reading increases. The rate of ingress of chlorides depends on the pore structure of concrete.

Fig.4. Experimental arrangement of Rapid Chloride Penetration Test.

3. RESULTS AND DISCUSSIONSaturated water absorptionFig. 5 shows the variation of saturated water absorption with water–cement ratio. Both the ceramic electrical insulator waste coarse aggregate concrete and the conventional concrete behave in a similar way and water absorption increases with increase in water–cement ratio. Water absorption is defined as the transport of liquids in porous solids caused by surface tension acting in the capillaries. In the present investigation, at the age of 28 days, the water absorption of ceramic electrical insulator waste coarse aggregate concrete for different water–cement ratios were 3.74–7.21% whereas for conventional concrete. it varies from 3.1% to 6.52% for respective water–cement ratios




Fig.5. w/c ratio VS water absorption %.

Volume of voids

Volume of voids present in concrete depends on the mix proportion and properties of aggregates used. Fig.6 shows the relationship between the water–cement ratio and the volume of voids in ceramic electrical insulator waste coarse aggregate concrete and conventional concrete. From the figure it can be seen that the volume of voids increases with increase in water–cement ratio for both the ceramic electrical insulator waste coarse aggregate concrete and theconventional concrete.

Fig.6. w/c ratio VS volume of voids %Sorptivity

After a period of sorption the initial rate of ingress observed decreases as the water has accessed all the larger capillary pores. Sorptivity is now occurring via finer pores and indicates the increasing importance of small pores with time. The average values of the test results of sorptivity are represented by bar a chart in Fig. 7. The sorptivity reduces with decrease in water– cement ratio for both ceramic electrical insulator waste coarse aggregate concrete and conventional concrete.




Fig.7. w/c ratio VS sorptivity

Chloride diffusion

As expected, the RCPT. charges reduce with decrease in water– cement ratio, the test results are presented in the Fig. 8. When capillary pores are relatively dry, absorption dominates and when they are relatively saturated, diffusion becomes the dominant transport process. In this investigation sorptivity specimens were dry and RCPT specimens were saturated. The concrete disc specimens for sorptivity and RCPT were similar in size, cut from the same cylindrical specimen and both the tests were conducted for a period of 6 hour duration

Fig.8. w/c ratio VS RCPT charge

Discussion

Theoretically, the factors controlling the permeation characteristics of concrete materials are the relative volume of paste matrix, the pore structure of the bulk matrix and the interfacial transition zone (ITZ) around the aggregate particle. Various studies show that the rougher the aggregate surface texture used in concrete for the better the bonding.




the difference of the test results of permeation characteristics between the ceramic electrical insulator waste coarse aggregate concrete and the conventional concrete is due to an increase in porosity of the ITZ [5], the reason perhaps may be due to the smooth surface texture of the ceramic electrical insulator waste coarse aggregate which is responsible for the bonding of aggregate with surrounding mortar. All the transport processes occur in the pore system and this depends on the total pore volume, pore size, threshold pore radii and the continuity of the capillary pores. The results from microstructural study seemed to suggest that the addition of mineral admixtures like pulverized fuel ash, grounded granulated blast furnace slag, micro silica, etc. to ceramic electrical insulator waste coarse aggregate concrete may improve the particle packing density of ITZ and in turn permeation characters will be improved.

Advantages: Economical Ambient temperature hardened material Energy efficiency Excellent resistance to water High temperature resistance Ability to consume waste Less maintenance required

Limitations: Quasi-brittle failure mode Low tensile strength Low toughness Formwork is needed Long curing time Working with cracks

4. CONCLUSIONSThe permeation characteristics of ceramic electrical insulator waste coarse aggregate

concrete were comparable to those of conventional concrete. The permeation characteristic values increase with increase in water–cement ratio

for both the ceramic electrical insulator waste coarse aggregate concrete and the conventional concrete.

The difference in the test results of permeation characters are due to the surface texture of ceramic electrical insulator waste coarse aggregate.

The permeation characteristics of ceramic electrical insulator waste coarse aggregate concrete may be improved by adding mineral admixtures like fly ash, slag, micro silica, etc

The ceramic electrical insulator waste coarse aggregate can be used for the production of concrete.

5.REFERENCES

[1] Neville AM. Properties of concrete. London: Pitman Publishing Limited; 1981[2] Park SG. Recycled concrete construction rubble as aggregate for new concrete, New Zealand; 1999.




[3] Khaloo AR. Crushed tile coarse aggregate concrete. Ceramic Concrete Aggregates 1995 [4] Topcu IB, Guncan NF. Using waste concrete as aggregate. Ceramic Concrete 1995[6] Ramamurthy K, Gumaste KS. Properties of recycled aggregate concrete. Indian Concrete J 1998[7] Basri HB, Mannan MA, Zain MFM. Concrete using waste oil palm shells asaggregate 1999[8].Milind Gupta &A K Pandey. Experimental studies on brick masonry in compression The Indian Concrete Journal –2012


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