Development and Evaluation of Vermiculite Tiles, Mortar and Concrete

Development and Evaluation of Vermiculite Tiles, Mortar and Concrete

Development and Evaluation of Vermiculite Tiles, Mortar and Concrete

Pannirselvam. N

Associate Professor,

SRM Institute of Science and Technology, Kattankulathur.

Former Professor and Head of the Department, Krishnasamy College of Engg. & Tech., Cuddalore, India

Santhoshini. R

Student of Undergraduate Program, Krishnasamy College of Engg. & Tech., Cuddalore, India

Abstract: Heat inherited through the roof of the building is the major cause of unconditioned building or the major load for the air conditioned building. Vermiculite being a phyllosilicate group of hydrated magnesium-aluminium-iron silicate with the suggested formula of [(Mg, Fe, Al)3(Al, Si)4O10 (OH)2.4H2O] is an inert material which resists the heat penetration. It is widely used as a filler material because of its low bulk density, high refractoriness, low thermal conductivity and adequate chemical inertness. This article mainly aims at the development and evaluation of vermiculite tiles which exhibits low water absorption, better strength properties and low heat penetration and better thermal insulation, when compared with traditional famous conventional tiles used for the flooring purpose. The usage of this material would decrease the structural weight. Various mixes were prepared using different percentage of vermiculite and water-cement ratio. The vermiculite tiles are light in weight which is easy to handle. The cement mortar cubes of dimensions 70.6 mm x 70.6 mm x 70.6 mm and mortar tiles of dimensions 304.8 mm x 304.8 mm x 6 mm were casted with replacement of fine aggregate with vermiculite in the ratio of 1:3 (C:F.A.). The fine aggregate was replaced with vermiculite in the fashion of 0.5 parts, 1 parts, 1.5 parts, 2 parts and 2.5 parts. The concrete cubes were casted in the dimensions of 150 mm x 150 mm x 150 mm with the mix ratio of 1:1.586:3.06 with the partial replacement of fine aggregate with vermiculite in the fashion of 50%, 75% and 80%.

Keywords: Better thermal insulation, Inertness, Light weight, Low heat penetration, Low water absorption, Reduced structural weight, Vermiculite tiles.

I.INTRODUCTION

Cost of energy and its crisis are alarming and adversely affecting the individual and the society in one form or the other. Thermal insulation (Barrier) has been considered as the best solution to reduce the energy load in individuals. Maximum heat transmission (more than 60%) takes place through roof surface of the buildings. Thermal insulations provides barrier for incoming heat into the building envelope and prevent inside heating. Use of thermally insulating materials impart comfort inside the room on one end and reduce the energy requirement for cooling in summer. Vermiculite is the key tool in considering energy thrifty buildings.

Fig. 1 Vermiculite

Vermiculite is an excellent mineral characterized by the high thermal insulation parameters which make it useful for many purposes, including those for manufacturing different kinds of fire-proofing materials as well as production of boards. Vermiculite occurs as golden-brown to greenish flakes. As a mineral it is distinguished by an outstanding ability to gain in volume (10-30 times) when exposed to high temperatures. This phenomenon is accompanied by water loss. Its bulk density in the natural form is between 600 and 1050 kg/m3 and after swelling 65-130 kg/m3. Because of low density, it is mainly used in expanding form.

Exfoliated vermiculite is also characterized by the properties of good sound insulation, good thermal insulation and good adhesion to different kinds of surfaces. Non-combustible vermiculite products emit neither smoke nor toxic fumes and make no hazard to the environment. Vermiculite is formed by hydration of certain basaltic minerals. Its moulded shapes, bonded with sodium silicate is used in high temperature insulation, refractory insulation, packing material, fire proofing of structural steel and pipes, as loose fill insulation, light weight aggregate for plaster and cementitious spray fire proofing.

Vermiculite is a rich mineral which is well known for its ability of exfoliation which expands rapidly when it is heated. It is categorized based on its grades, density and many factors which are broadly classified into crude and exfoliated vermiculite but vermiculite is mostly used in exfoliated form that serves various applications.

Approximately 25-30% of the total energy consumption in the world is used in buildings. About 80% of the energy consumed in commercial and residential buildings is used for space heating and cooling. An important way of achieving better energy efficiency in buildings is to improve their thermal insulation properties. Reduction of the heat loss in building decreases the consumption of energy and, thus, reduces the cost if heating and cooling. Enhanced thermal protection is a therefore a prerequisite to construct or rehabilitate buildings to reach a reasonable energy consumption, satisfactory thermal comfort conditions, and low operational costs. Energy saving can be obtained by insulation since a significant part of heat losses or heat gains occurs through walls and ceilings.

An analysis of conduction heat transfer through structure is of great importance in civil engineering problems, such as heat flow into a building in energy-efficient building design, thermal loading of structures due to diurnal variations of temperature, planning and design of building for thermal comfort, design of radiation shields in nuclear power stations, analysis of bridge deck and other exposed structures for solar thermal loading, etc.

1. River Sand

   Table 3 Physical Properties of fine aggregate

   Sl. No.	Description	Value
   1.	Specific Gravity	2.5
   2.	Fineness Modulus	5.495
   3.	Bulk Density	1648 kg/m3
   4.	Dry Density	1575 kg/m3
   5.	Zone	II

2. Vermiculite

The vermiculite is a highly thermal insulating material which can be used as a filler material in the concrete for avoiding the effect of heat inheritance in the roof of the building.

Table 4 Physical properties of Vermiculite

A. Cement

Sl. No.	Description	Value
1.	Fineness Modulus	6.965
2.	Specific Gravity	1.1
3.	Bulk density	388 kg/m3
4.	Dry Density	607 kg/m3

II.MATERIALPROPERTIES

The chemical and physical properties of the Portland Pozzolona Cement are given in the table 1 & 2.

Table 1 Chemical properties of the cement

1. Coarse Aggregate

   The proportioning of coarse aggregate 60% of 20 mm and 40% of aggregate greater than 12.5 mm is used in the concrete. The physical properties of the coarse aggregate are given in table 5.

   Table 5 Physical properties of coarse aggregate

   Sl. No.	Description	Value
   1.	Fineness Modulus	4.91
   2.	Secific Gravity	2.65
   3.	Water absorption	0.35%

   Table 2 Physical properties of cement

   Sl. No.	Composition	Percent
   1.	SiO2	19.4
   2.	Al2O3	5.6
   3.	Fe2O3	2.4
   4.	CaO	63.1
   5.	MgO	2.6
   6.	SO3	2.9
   7.	Na2O	0.8
   8.	K2O	1
   9.	CI	0.01
   10.	Insoluble material	3.3
   11.	Loss on ignition	3.3

   III. MIX PROPORTIONS FOR SPECIMENS

   1. Vermiculite Mortar Cubes and Tiles

      The vermiculite mortar cubes were prepared in the ratio of 1:3 with the partial replacement of river sand by vermiculate in the following mix ratios in table 6. The mortar cubes were casted by considering both volume batching and weight batching.

      Sl. No.	Description	Value	Remarks
      1.	Specific gravity	3.10	Tested results are satisfactory as per IS 1489 part-1 (1991)
      2.	Consistency	33%
      3.	Initial setting time	40 mins.
      4.	Final setting time	350 mins
      5.	Soundness	10 mm
      6.	Fineness	10%

      Table 6 – Vermiculite Mortar Cubes (Vol., wt. batching) and tiles

      Sl. No.	Mix Proportion	Ratio
      1.	C:S	1 : 3
      2.	C:VM	1 : 3
      3.	C:S:VM	1 : 0.5 : 2.5
      4.	C:S:VM	1 : 1 : 2
      5.	C:S:VM	1 : 1.5 : 1.5
      6.	C:S:VM	1 : 2 : 1
      7.	C:S:VM	1 : 2.5 : 0.5

   2. Fine Aggregate

The physical properties of fine aggregate and vermiculite that are used in the manufacture of vermiculite tiles, mortar and concrete are presented in table 3 & 4.

1. Vermiculite Concrete

   The vermiculite concrete was casted in the grade M20 with mix ratio of 1:1.586:3.06.

   Table 7 Vermiculite Concrete

   Sl. No.	Percentage of Sand and VM
   1.	Conventional Concrete (100% sand and 0% VM)
   2.	50% Sand , 50% VM
   3.	75% Sand , 25% VM
   4.	80% Sand , 20% VM

   IV.CASTING OF SPECIMENS

   1. The vermiculite mortar cubes were casted in the cube moulds of dimension 70.6 mm x 70.6 mm x 70.6 mm.

   2. The vermiculite concrete cubes were casted in the cube moulds of dimension 150 mm x150 mm x150 mm.

   3. The vermiculite tiles were casted in the mould of dimension 304.8 mm x 304.8 mm x 6 mm.

Fig. 5. Mixing of specimens

Fig. 6. Mortar Cubes (70.6 mmx70.6 mmx70.6 mm)

Fig. 7. Concrete Cubes (150 mmx150 mmx150 mm)

Fig. 8. Vermiculite Tiles (304.8 mm x 304.8 mm x 304.8 mm)

V. RESULT AND ANALYSIS

The casted specimens after 3, 7, 14 and 28 days of curing are subjected to the following test:

• Compression Test

• Durability Test

• Thermal Conductivity test.

A. Compression Test

1. Mortar Cubes (Weight Batching)

   Table 8 Compressive strength for wt. batched cubes in N/mm2

   Ratio	3 Days	7 Days	14 Days	28 Days
   C:S 1:3	12	23.5	34	43.5
   C:VM 1:3	0.8	0.8	0.8	1.0
   C:S:VM 1:0.5:2.5	1	1	1	1.2
   C:S:VM 1:1:2	1.2	1.4	1.8	2.4
   C:S:VM 1:1.5:1.5	1.4	1.6	2.0	3.0
   C:S:VM 1:2:1	1.6	1.8	2.2	3.4
   C:S:VM 1:2.5:0.5	2.2	3.4	4.6	5.8

2. Mortar Cubes (Volume Batching)

   Ratio	7 Days	28 Days
   C:S 1:3	23.47	43.54
   C:VM 1:3	3	3.6
   C:S:VM 1:0.5:2.5	3.6	4.0
   C:S:VM 1:1:2	3	4.4
   C:S:VM 1:1.5:1.5	3.41	6.01
   C:S:VM 1:2:1	6.62	9.02
   C:S:VM 1:2.5:0.5	9	12.23

   Table 9 Compressive strength for volume batched cubes

3. Concrete Cubes

Table 10 Compressive strength for concrete cubes

4) Concrete Cubes

Table 14 TC for concrete cubes

Ratio	7 Days	28 Days
Conventional Concrete	26.49	31.91
50% Sand, 50% VM	8.71	10.08
75% Sand, 25% VM	12.22	17.15
80% Sand, 20% VM	10.8	14.3

Sl. No.	Ratio	Temp
1.	100% S, 0% VM	36.25
2.	50% S, 50% VM	23.62
3.	75% S, 25% VM	24.14
4.	80% S, 20% VM	25.98

B). Thermal Conductivity (TC)Test

1. Mortar Cubes (Weight Batching)

   Table 11 TC for weight batched mortar cubes

   Sl. No.	Ratio	Temp.
   1.	1 : 3	32.61
   2.	1 : 3	21.26
   3.	1 : 0.5 : 2.5	22.69
   4.	1 : 1 : 2	23.86
   5.	1 : 1.5 : 1.5	23.08
   6.	1 : 2 : 1	24.39
   7.	1:2.5:0.5	25.92

2. Mortar Cubes (Volume Batching)

   Table 12 TC for weight batched mortar cubes

   Sl. No.	Ratio	Temp.
   1.	1 : 3	32.54
   2.	1 : 3	24.10
   3.	1 : 0.5 : 2.5	24.54
   4.	1 : 1 : 2	24.67
   5.	1 : 1.5 : 1.5	25.09
   6.	1 : 2 : 1	25.35
   7.	1:2.5:0.5	25.43

3. Vermiculite Tiles

SL. NO.	RATIO	STRENGTH	TEMP.
1.	1 : 3	9.84	30.26
2.	1 : 3	2.46	21.16
3.	1 : 0.5 : 2.5	4.37	21.65
4.	1 : 1 : 2	5.47	22.65
5.	1 : 1.5 : 1.5	6.56	23.12
6.	1 : 2 : 1	6.56	23.69
7.	1:2.5:0.5	8.20	25.03

Table 13 TC for volume batched mortar cubes

VI CONCLUSION

The developed high-temperature heat-insulating cement-based materials produced by using expanded vermiculite can be used in thermal power plants with the hot-wall temperature as an alternative to lightweight chamotte components and fibrous heat insulators. Since the mix ratios are one of the significant parameters influencing the strength and the thermal conductivity of cement-based composites, results of the TC and strength as a function these parameters were compiled. Thermal conductivity decreased by the increase in the content of the expanded vermiculite in the mix. The thermal conductivity for the specimens with complete replacement of river sand by expanded vermiculite was observed to be lower than the other specimens with partial replacements. The development of the models based on the existing experimental data was carried out to predict material properties for the design of the composite materials.

In order to develop or increase the performance of similar materials in the future, mix proportions may be optimized by taking into account different mix proportions and curing conditions. Cement based material produced by expanded vermiculite can be used as a new material and structural component with good physical material properties for housing and other structures. Composites to be produced with expanded vermiculite may become viable and promising construction material for the point of view of energy conscious and ecological design in the future. The self weight of the concrete is also reduced by the incorporation of the expanded vermiculite in the concrete composite.

The vermiculite concrete tends to show better strength properties when the river sand is replaced by 25% when compared with the other proportions. The graph for strength values of the vermiculite concrete is found to be lower for the 50% replacement of the river sand and tends to increase further for 25% replacement and drops gradually for the 20% replacement of river sand by the expanded vermiculite. While the graph for the thermal insulation of the specimens increased with the increase in the content of expanded vermiculite. The strength parameters and the thermal conductivity of the vermiculite composites for both mortar cubes and concrete cubes tends to decrease with the increase in the content of expanded vermiculite.

The heat in the roof of the building can be reduced to a great extent by incorporating the expanded vermiculite and the required strength can be achieved by adding considerable amount of admixtures to the composites. Vermiculite tiles exhibits low water absorption, better strength properties and low thermal conductivity which can be used in roof slab of the buildings, computer rooms and cold storages, etc. The shrinkage and creep resistance is one of the greater advantages

in vermiculite tiles and the concrete and it does not undergo any chemical reaction with concrete and it is eco-friendly.

ACKNOWLEDGEMENT

The authors thank TNSCST for the grant provided to carry out the project and the authors also thank the management of Krishnasamy College of Engg. & Tech., for their constant support and encouragement in carrying out this project.

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