ABSTRACT
Construction Industry is always on hunt for Innovative Material and Innovative construction technologies. Concrete is the second largest material used on Earth after water. Concrete has proved its worth in the construction industry for being the most robust and durable. However, “Sustainable Concrete” is the need of the hour. Production of conventional concrete is quite an energy intensive process. A lot of energy, virgin materials, and Co2 production is associated with its making.
Present study is an attempt to study the use of Industrial Waste Product and an Innovative manufactured product as a replacement of Coarse aggregates that constitutes to almost about 70% volume of concrete. Materials taken up for the study are Grog – Fired Clay brick waste and SINTAGG – Synthetic aggregates made of sintered flyash.
The study evaluates the efficacy of M25 grade of Concrete produced replacing the conventional kapachi 100% both by Grog and SINTAGG. Cubes and cylinders cast using this concrete will be tested in Compression and Tension. Workability of concrete achieved was 80-100 mm for Grog based concrete and was 150 mm for SINTAGG based concrete. Density of cubes for Control, Grog based, SINTAGG based was found to be 2500kg/m3, 2200kg/m3, 2000kg/m3 respectively. This proves the use of such innovative aggregates in making of Light Weight Concrete.
CHAPTER: 1 INTRODUCTION
1.1 Background:
Aggregates are the important constituents in the concrete composite that help in reducing shrinkage and impart economy to concrete production. Most of the aggregates used are naturally occurring aggregates, such as crush rock, gravel and sand which are usually chemically interactive or inert when bonded together with cement. On the other hand, the modern technological society is generating substantially high amounts of solid wastes both in municipal and industrial sectors; posing an engineering challenging task for this effective and efficient disposal. Hence, partial or full replacement of aggregates by the other compatible materials like sintered fly ash, crushed rock dust, quarry dust, glass powder, recycled concrete dust, and others are being researched from past two decades, in view of conserving the ecological balance. Even though, use of several types of industrial solid wastes like metallurgical waste, glass pieces, fly ash, quarry dust, tyre and rubber waste, crushed concrete waste, sludges and others in making good field concrete is being effectively done at European countries, U.S.A., U.K., and Australia; Asian countries could not gear up to that level to match with those countries . Therefore, resource exploitation and waste disposal problems are currently rocking the sustainable development in those countries (including India).
1.2 Scope of work:
• Identification and procurement of innovative and industrial waste such as Grog and SINTAGG from the Ahmedabad city and use as a full replacement of coarse aggregate in structural concrete.
• Assessment of physical properties of lightweight aggregates and normal weight aggregates.
• Mix design of lightweight concrete and normal concrete and Casting and testing of cubes and cylinder specimens of lightweight concrete and normal concrete for 28 day compressive strength and tensile strength.
• Comparison of compressive and tensile strength on the basis on experimental results and analytical results.
CHAPTER: 2 LITERATURE SURVEY
2.1 Classification of Lightweight Concrete :
Lightweight concrete (LWC) can be broadly classified as,
1. LOW DENSITY CONCRETE:
These are employing chiefly for insulation purposes. With low unit weight, seldom exceeding 800 kg/m³, heat insulation value are high. Compressive strength is low, regarding from about 0.69 to 6.89 N/mm2.
2. MODERATE STRENGTH CONCRETE
The use of these concrete requires a fair degree of compressive strength, and thus they fall about midway between the structural and low density concrete. These are sometimes designed as ‘fill’ concrete. Compressive strength are approximately 6.89 to 17.24 N/mm² and insulation values are intermediate.
3. STRUCTURAL CONCRETE
Concrete with full structural efficiency contain aggregates which fall on the other end of the scale and which are generally made with expanded shale, clay, slates, slag, and fly-ash. Minimum compressive strength is 17.24 N/mm². Most structural LWC are capable of producing concrete with compressive strength in excess of 34.47 N/mm². The concrete may consist of entirely lightweight aggregates or a combination of normal and lightweight aggregates. For practical reasons, it is common practice to use normal sand as fine aggregate and lightweight coarse aggregate of maximum size 19mm. Since the unit weight of structural LWC are considerably greater than those of low density concrete, insulation efficiency is lower. However, thermal insulation values for structural LWC are substantially better.
2.2 Classification of Lightweight Aggregates :
Lightweight aggregates can be classified in two categories namely natural lightweight aggregates and artificial lightweight aggregates.
As a part of study in the project, lightweight aggregate concrete made with two types of lightweight aggregates has been utilized. Thus, we shall study these two types of lightweight aggregates in detail.
Natural Lightweight Aggregate Artificial Lightweight Aggregate
a) Pumice
b) Diatomite c) Scoria
d) Volcanic Cinders e) Sawdust
f) Rice Husk a) Artificial Cinders b) Coke Breeze
c) Foamed Slag
d) Expanded Clay
e) Expanded Shales and Slate
f) Sintered Flyash
g) Exfoliated Vermiculite
h) Expanded Perlite
i) Thermocole Beads
Table 1: Classification of Lightweight Aggregates
1. Expanded Clay
When certain glass and shales are heated to the point of incipient fusion, they expand or what is termed as bloat to many times their original volume on account of the formation of gas within the mass at fusion temperatures. The cellular structure so formed is retained on cooling and product is used as lightweight aggregate. “Haydite”, “Rocklite”, “Gravelite”, “LECA”, “Aglite”, “Kermazite”, are some of the patent names given to bloated clay or shale manufactured in various western countries adopting different techniques.
2. Sintered Fly Ash (Pulverized Fly Ash)
Fly ash is finely divided residue, comprising of spherical glassy particles, resulting from the combustion of powdered coal. By heat treatment these small particles can be made to combine thus forming porous pellets or nodules which have considerable strength. The fly ash is mixed with limited amount of water and is first made into pellets and then sintered at a temperature of 1000֠ to 1200֠ C. The sintering process is similar to that used in manufacture of Portland cement. Sintered fly ash is one of the most important types of structural lightweight aggregate used in modern times. It has high strength/density ratio and relatively low drying shrinkage.
2.3 Industrial Waste – Grog :
• Grog is a granular material that has been crushed down from fired brick, or other pre-fired ceramic product.
• Fire bricks are used in foundry bed and walls; and lining of chimney, cooking chamber in wood fired ovens etc.
• Inside lining of Crucible furnace, Cupola furnace, Induction furnace etc. that are used for melting the metal to be used to make a metal casting are made up of fire bricks.
2.3.1 GENESIS OF GROG :
FIRE BRICKS
Fire bricks are the products manufactured (as per IS: 6 and IS: 8 specifications) from refractory chamotte, plastic, and non plastic clays of high purity. The different raw materials are properly homogenized and pressed in high capacity presses to get the desired shape and size. Later, these are fired in oil-fired kiln at
Apart from this, they exhibit excellent non susceptibility to chemicals, thermal shocks, and carbon deposits. The sample fire bricks and its application in furnace are depicted in Figs.1 and 2, respectively.
Fig 1 Fire Bricks samples. Fig. 2 – Fire Bricks used in a typical furnace.
GROG (Spent Fire Bricks SFB)
Due to the exposure to continuous high temperature (i.e. 1,000… 1,200ºC) for a period of 10 to 15 days, they lose some of the physical and mechanical properties and need to be replaced by fresh fire bricks, and is being done usually done once in fortnight. Then, the SFB is an industrial solid waste to be disposal off properly and Fig. 3 shows the broken SFB.
Fig. 3 – Broken fire bricks after complete usage
• After 25 to 30 tonne production of metal , inside fire brick lining of furnace needs to reconstruct.
• This reconstruction of lining generates about waste of 300 bricks.
• As per data from Ahmedabad Engineering And Manufacturing Association , around 900 registered foundries are located in Ahmedabad region.
• Around 800-900 kg waste generates from one foundry.
Supplier of Aggregates
Name of the Company: GBC India
A/408, Neelkanth Palace, 100 ft Road, Satellite, Ahmedabad. M: +91 98250 70625
W: www.gbcindia.org
Proprietor: Mr. Sandeep Vidwans
Sandeep Vidwans founded GBC in 2005 with a vision to empower environment by providing innovative products designing, solutions aiming to improve energy efficiency in buildings, keeping environment, and socio-economic developments
GBC currently offers a wide variety of eco-friendly products for building material purpose. The two types of lightweight aggregate for lightweight concrete used in this study have been procured from GBC India.
Figure 4 Light Expanded Clay Aggregates Figure 5 Sintered Pulverized Fly Ash Aggregates
Chapter 3: Literature Review
3.1 Research Papers
‘Hollow Core Slabs in Construction Industry’
Vidya Jose, Dr.P. Rajeev Kumar (M tech Student, Dept of Civil Engineering, Toc H Institute of Engineering and Technology, Arakunnam, Kerala, India & Professor, Dept of Civil Engineering, Toc H Institute of Engineering and Technology, Arakunnam, Kerala, India) Published in International Journal of Innovative Research in Science, Engineering and Technology
A hollow core slab is a precast prestressed concrete member with continuous voids provided to reduce weight and cost. They are primarily used as a floor deck system in residential and commercial buildings as well as in parking structures because they are economical, have good fire resistance and sound insulation properties, and are capable of spanning long distances with relatively small depths. Structurally, a hollow core slab provides the efficiency of a prestressed member for load capacity, span range, and deflection control. Hollow core slabs can make use of pre stressing strands, which allow slabs with depths between 150 and 260 mm to span over 9 meters. When used in buildings, several hollow core slabs are placed next to each other to form a continuous floor system. The small gap that is left between each slab is usually filled with a non- shrink grout. To give the floor a smooth finished surface, a topping slab overlay, typically 5cm deep is poured on the top surface of the hollow core slabs. The design concepts, manufacture and the erection techniques of Hollow core slabs are discussed in detail.
Designing for sustainable development not only involves using recyclable building materials and reducing energy consumption while building, but it also implies better use of available building materials, production systems with less environmental burden, products with higher performances, design systems in line with new demands for flexibility and adaptability to future needs. Hollow core slabs enable a very efficient industrialized production. By ensuring that the slabs are produced under a strict quality assurance program and that these are safely transported, erected on site and that proper detailing is ensured, a semi-monolithic structure is achieved with improved performance of the structural system with respect to fire resistance, safety against progressive collapse and transfer of horizontal loads. Hollow core slabs are used for a variety of applications in low and high-rise commercial residential and industrial buildings. It provides an answer to most of the present market demands and challenges for the building industry: structural efficiency, low material consumption, highly automated and environment friendly production process, high concrete strength, slender floor thickness, and possibilities for reuse and recycling at the end of the life cycle.
‘STRENGTH AND DURABILITY OF LIGHTWEIGHT AND NORMAL WEIGHT CONCRETE’
Husain Al-Khaiat & Naseer Haque (Assoc. Prof., Dept. of Civ. Engrg., Kuwait Univ., P.O. Box
5969, Safat, Kuwait) & (Assoc. Prof., School of Civ. Engg., Univ. College, ADFA, Australia)
Published in Journal of Materials in Civil Engineering ASCE
Investigation of the long-term strength development and durability of lightweight aggregate concretes (LWAC’s) and a normal weight concrete (NWC) under hot dry and hot humid coastal exposure conditions. This paper reports the strength development and durability characteristics of 35- and 50-MPa NWC specimens exposed to the seaside up to an age of 9 months. The water penetrability, depth of carbonation, sulfate and chloride penetration have been investigated for both concrete mixes.
Workable and Cohesive LWCs of 35 and 50 MPa 28-day cube compressive strength with a unit weight of 1,800 kg/m3 were produced. The 50-MPa LWAC required 10% more total cementitious contents than the corresponding NWC. The indirect tensile strength, modulus of rupture, and modulus of elasticity of the NWC50 was; 20, 50, and 30% higher than the corresponding value of the LWC50, respectively, at the age of 9 months. The water penetrability of LWCs seems to be more sensitive to the extent of initial curing than it is for NWCs. The water penetrability of LWC50 in the regime was 1/3 more than that of the NWC50 in the same exposure condition at the age of 9 months. On the whole, the depth of carbonation of NWC50 was less than that in the LWC 50; nonetheless, after 7 days of water curing and subsequent exposure to a seaside, the carbonation depth of the two concretes was similar. Sulphate and chloride concentrations in LWC50 were somewhat higher than that in NWC50
DURABILITY PERFORMANCE OF LIGHTWEIGHT AGGREGATE CONCRETE FOR HOUSING CONSTRUCTION’
Fahrizal Zulkarnain, Mahyuddin Ramli (PhD Candidate, School of Housing, Building and Planning, Universiti Sains Malaysia, Malaysia & Dean, School of Housing, Building and Planning, Universiti Sains Malaysia, Malaysia) Published in 2nd INTERNATIONAL CONFERENCE ON BUILT ENVIRONMENT IN DEVELOPING COUNTRIES (ICBEDC 2008)
Durability can be defined as the ability of material to withstand the effects of its environment. In the building material its may be interpreted as chemical attack, water absorption and carbonation. Chemical attack usually encountered as aggressive groundwater, particularly sulphate, polluted air and spillage of reactive liquids. A hemical aspect of durability is the stability of the material itself, particularly in the presence of moisture. Concrete made with lightweight aggregate exhibit a higher moisture movement than is the case with normal weight concrete. Based on the a 24 hr absorption test, lightweight aggregate generally absorbs from 5 to 20 percent by weight of dry aggregate, depending on the pore structure of the aggregate. The important difference is that the moisture content in lightweight aggregates is largely absorbed into the interior of the particles whereas in normal weight aggregates it is largely surface moisture. Rate of absorption in lightweight aggregates is a factor which also has a bearing on mix proportioning, handling, and control of concrete, and depends on the aggregate particle surface pore characteristics plus other factors.
The durability of lightweight aggregate concrete depends of some factors. Like a freeze/thaw behavior, chemical resistance, abrasion resistance, water absorption, permeability, and carbonation. And for the thermal behavior for lightweight aggregate concrete are less than normal weight concrete made with the majority of aggregate types. Whatever design method is used, it is necessary to ensure that the structure evolved is not only safe against collapse under vertical loading and stable against overturning forces but that its deformations under load are not excessive. Durability is another complex structural property which may be regarded as an ultimate limit state in certain conditions. It requires careful consideration of the conditions of uses, of the materials and workmanship employed and of the regime of inspection, maintenance and repairs which it is practicable to enforce in particular cases.
3.2 Codes & Standards
1. IS 10297 – 1982: CODE OF PRACTICE FOR DESIGN AND CONSTRUCTION OF FLOORS AND ROOFS USING PRECAST REINFORCED/PRESTRESSED CONCRETE RIBBED OR CORED SLAB UNITS (Reaffirmed 2008)
2. IS 456 – 2000: PLAIN AND REINFORCED CONCRETE – CODE OF PRACTICE
3. IS 2386 (Part I) – 1963: METHODS OF TEST FOR AGGREGATES FOR CONCRETE (PART I PARTICLE SIZE AND SHAPE) (Reaffirmed 1997)
4. IS 2386 (Part III) – 1963: METHODS OF TEST FOR AGGREGATES FOR
CONCRETE (PART Ill SPECIFIC GRAVITY, DENSITY, VOIDS, ABSORPTION AND BULKING) (Reaffirmed 1997)
5. IS 10262 – 2009: CONCRETE MIX PROPORTIONING – GUIDELINES
6. ASTM C330: STABDARD SPECIFICATION FOR LIGHTWEIGHT AGGREGATES FOR STRUCTURAL CONCRETE
7. ACI 211.2-98: STANDARD PRACTICE FOR SELECTING PROPORTIONS FOR STRUCTURAL LIGHTWEIGHT CONCRETE (Reapproved 2004)
8. ACI 213R-03: GUIDE FOR STRUCTURAL LIGHTWEIGHT AGGREGATE CONCRETE
9. ACI318-08: BUILDING CODE REQUIREMENTS FOR STRUCTURAL CONCRETE
10. BUBBLE DECK DESIGN GUIDE FOR COMPLIANCE WITH BCA USING AS3600 AND EC2, Bubble Deck Australia & New Zealand
3.3 Books
1. M.S Shetty, ‘Concrete Technology – Theory and Practice’, S. Chand & Company Ltd
2. Comite Euro-International du Beton (CEB), ‘Lightweight Aggregate Concrete’ Manual of Design & Technology, The Contruction Press, London, Published 1977
Chapter 4: Physical Properties
This chapter includes the assessment of important physical properties of both the types of lightweight aggregates as well as normal aggregates and fine aggregates (sand). The following physical properties of these materials have been assessed.
1. Sieve Analysis
2. Bulk Density
3. Specific Gravity
4. Moisture Content
5. Water Absorption
4.1 Physical Properties of Lightweight Aggregates
4.1.1 Sieve Analysis
Test: Sieve Analysis & Determination of Fineness Modulus
Procedure: As per IS 2386 Part I (1963): Methods of Test for Aggregates for Concrete
(Part I Particle Size and Shape
Results for SINTAGG:
Sieve Analysis (Sintered Fly Ash Aggregates)
Sample Weight = 3 Kgs
Sr
No IS Sieve Size Weight Retained (Kgs) Cumulative Weight Retained (Kgs) Cumulative Percentage Retained Cumulative Percentage Passing
1 80 mm 0 0 0 100
2 40 mm 0 0 0 100
3 20mm 0 0 0 100
4 16 mm 0.042 0.042 1.4 98.6
5 12.5 mm 0.43 0.472 15.733 84.267
6 10 mm 0.98 1.452 48.400 51.600
7 4.75 mm 1.51 2.962 98.733 1.267
8 2.36 mm 0.038 3 100.000 0.000
9 1.18 mm 0 3 100.000 0.000
10 600 microns 0 3 100.000 0.000
11 300 microns 0 3 100.000 0.000
12 150 microns 0 3 100.000 0.000
Total 3 – 664.267 –
Fineness Modulus (F.M) 6.643
Sample As per Test As per Supplier
SINTAGG 4.75-12.5 mm 4.75-12.7 mm
Table 3: Sieve Analysis – Sintered Pulverized Fly Ash Aggregates
Figure 7: Sieve Analysis of Sintered Pulverized Fly Ash Aggregates
Conclusion: Conforming to ASTM C330 Standard Specification for Light weight
Aggregates for Structural Concrete
Sieve Analysis(Grog)
Sample Weight=20kgs
Sr. No. Sieve size(mm) Weight retained
(kgs) Cumulative weight retained (kgs) Cumulative Percentage Retained Cumulative percentage Passing
1 80 0 0 0 100
2 40 0 0 0 96
3 20 0.8 0.8 4 35
4 10 12.2 13 65 6
5 4.75 5.8 18.8 94 0
6 2.36 0.2 20 100 0
7 1.18 0 20 100 0
8 600microns 0 20 100 0
9 300microns 0 20 100 0
10 150microns 0 20 100 0
Total 663
Fineness Modulus(F.M.) 6.63
4.1.2 Loose Bulk Density
Test: Determination of Loose Bulk Density
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Results:
Sample Loose Bulk Density (kg/m3)
As per Test As per Supplier
SINTAGG 874.81 >800
Grog NA
Table 4 Results of Loose Bulk Density of Lightweight Aggregates
Conclusion: Conforming to ASTM C330 Standard Specification for Light weight
Aggregates for Structural Concrete
4.1.3 Specific Gravity
Test: Determination of Specific Gravity Factor
Procedure: As per ACI 211.2-98 – Standard Practice for Selecting Proportions for
Structural Lightweight Concrete
Results:
Sample Specific Gravity Factor
SINTAGG 1.80
Grog 2.35
Table 5: Results of Specific Gravity Factor for Lightweight Aggregates
Figure 8 Specific Gravity Test for Lightweight Aggregates
1.4 Moisture Content
Test: Determination of Moisture Content
Procedure: As per ACI 211.2-98 – Standard Practice for Selecting Proportions for
Structural Lightweight Concrete
Results:
Sample Moisture Content (%)
SINTAGG 2
Grog 1.5 1.511111
Table 6: Results of Moisture Content for Lightweight Aggregates
4.1.5 Water Absorption
Test: Determination of Water Content
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Results:
Sample Water Absorption (%)
As per Test As per Supplier
SINTAGG 16 <=16
Grog 13
Table 7: Results of Water Absorption for Lightweight Aggregates
4.2 Physical Properties of Fine Aggregates (Sand)
4.2.1 Sieve Analysis
Test: Sieve Analysis and Determination of Fineness Modulus & Zone of Sand
Procedure: As per IS 2386 Part I (1963): Methods of Test for Aggregates for Concrete
(Part I Particle Size and Shape)
Results:
Sieve Analysis (Sand)
Sample Weight = 1 kgs
Sr
No
IS Sieve Size Weight Retained (kg) Cumulative Weight Retained (kg) Cumulative Percentage Retained Cumulative Percentage Passing
1 80 mm 0 0 0 100
2 40 mm 0 0 0 100
3 20mm 0 0 0 100
4 16 mm 0 0 0 100
5 12.5 mm 0 0 0 100
6 10 mm 0 0 0 100
7 4.75 mm 0 0 0 100
8 2.36 mm 0.045 0.045 4.5 95.5
9 1.18 mm 0.08 0.125 12.5 87.5
10 600 microns 0.114 0.239 23.9 76.1
11 300 microns 0.46 0.699 69.9 30.1
12 150 microns 0.26 0.959 95.9 4.1
13 75 microns 0.02 0.979 97.9 2.1
Total 1.0 – 304.6 –
Fineness Modulus (F.M)
3.05
Table 8: Sieve Analysis of Sand
Conclusion: Grading Zone III as per IS 383: SPECIFICATION FOR COARSE AND FINE AGGREGATES FROM NATURAL SOURCES FOR CONCRETE
4.2.2 Loose Bulk Density
Test: Determination of Loose Bulk Density
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Result:
Sample Loose Bulk Density (kg/m3)
Sand 1753.08
4.2.3 Specific Gravity
Table 9: Results of Loose Bulk Density for Sand
Test: Determination of Specific Gravity
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking
Result:
Sample Specific Gravity
Sand 2.78
Table 10: Results of Specific Gravity for Sand
4.2.4 Moisture Content
Test: Determination of Moisture Content
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Result:
Sample Moisture Content (%)
Sand 2.86
Table 11: Results of Moisture Content for Sand
4.3 Physical Properties of Normal Aggregates
4.3.1 Sieve Analysis
Test: Sieve Analysis and Determination of Fineness Modulus
Procedure: As per IS 2386 Part I (1963): Methods of Test for Aggregates for Concrete
(Part I Particle Size and Shape)
Results:
Sieve Analysis (Coarse Aggregates)
Sample Weight = 3 Kgs
Sr
No IS Sieve Size Weight Retained (Kgs) Cumulative Weight Retained (Kgs) Cumulative Percentage Retained Cumulative Percentage Passing
1 80 mm 0 0 0 100
2 40 mm 0 0 0 100
3 20mm 0 0 0 100
4 16 mm 0.06 0.06 2 98
5 12.5 mm 0.7 0.76 25.33 74.67
6 10 mm 1 1.76 58.67 41.33
7 4.75 mm 1.24 3 100.00 0
8 2.36 mm 0 3 100.00 0
9 1.18 mm 0 3 100.00 0
10 600 microns 0 3 100.00 0
11 300 microns 0 3 100.00 0
12 150 microns 0 3 100.00 0
13 75 microns 0 3 100.00 0
Total 3 – 786.00 –
Fineness Modulus (F.M)
7.86
Table 12: Sieve Analysis of Coarse Aggregates
4.3.2 Loose Bulk Density
Test: Determination of Loose Bulk Density
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Result:
Sample Loose Bulk Density (kg/m3)
Coarse Aggregates 1783.18
Table 13: Results of Loose Bulk Density of Coarse Aggregates
4.3.3 Specific Gravity
Test: Determination of Specific Gravity
Procedure: As per IS 2386 Part III (1963): Methods of Test for Aggregates for Concrete
(Part III Specific Gravity, Density, Voids, Absorption and Bulking)
Result:
Sample Specific Gravity
Coarse Aggregates 2.72
Table 14: Results of Specific Gravity of Coarse Aggregates
Chapter 5: Mix Design
5.1 Mix Design of Lightweight Concrete
In absence of any relevant Indian Standard Code for mix design of lightweight concrete, here standard code from ‘American Concrete Institute’ has been used. As the procedure to mix design of lightweight concrete is a new concept. Here is a step by step procedure for the same.
Code of reference: ACI 211.2-98 – Standard Practice for Selecting Proportions for
Structural Lightweight Concrete
5.1.1 Lightweight Concrete with SINTAGG lightweight aggregates
Predefined Parameters:
Bulk density of SINTAGG: 875 kg/m3
Water Absorption of SINTAGG: 16% Specific Gravity Factor for SINTAGG: 1.80
Fineness Modulus of fine aggregates: 3.0
Ordinary Portland Cement (Grade-53) conforming to IS Non-air entrained concrete is required
Lightweight concrete is required for a floor slab having 28-day compressive strength as
25 Mpa
Step1: Choice of Slump
As per Table 3.1 of ACI 211.2-98,
Maximum slump required for floor slabs is 75mm (3inches)
Step2: Choice of Nominal Maximum Size of Aggregate
Here, maximum size aggregates is 12.5mm
Step3: Estimation of Mixing Water & Air Content
As per Table 3.2 of ACI 211.2-98,
For maximum slump of 75mm, non air entrained concrete and maximum size of aggregates upto 12.7mm,
Mixing Water Content – 217 kg/m3
Step 4: Selection of Approximate W/C
As per Table 3.3 of ACI 211.2-98,
For target strength of 34.5 Mpa (5000 psi) & non air entrained concrete,
W/C – 0.48
Step 5: Calculation of Cement Content
Here, W/C = 0.48 & Water = 217 kg/m3
Therefore, 202/C = 0.48
Cement = 450 kg/m3
Step 6: Estimation of Lightweight Coarse Aggregate Content
As per Table 3.5 of ACI 211.2-98,
For fineness modulus of sand as 3.0 & max size of aggregates upto 12.7mm, Fraction of coarse aggregate per unit volume of concrete = 0.61
Volume of coarse aggregate per unit volume of concrete = 0.61 x 1 x 875
= 534 kg/m3
SINTAGG (per m3 of concrete) = 534 kg/m3
Step 7: Estimation of Fine Aggregate Content
The quantity of fine aggregate is determined by difference
As per Table 3.6 of ACI 211.2-98,
For specific gravity factor of 1.81 & considering 4% air entrainment, Estimated unit weight of lightweight concrete = 1935 kg/m3
Now, Water = 217 kg/m3
Cement = 450 kg/m3
Coarse Aggregate = 534 kg/m3
Total = 1935 kg/m3
Fine Aggregates = Total – (Water + Cement + Coarse Aggregate) Fine Aggregates = 732 kg/m3
Mix Proportions (kg/m3) for LWC with SINTAGG:
Water 217
Cement 450
Coarse Aggregates (SINTAGG) 534
Fine Aggregates (Sand) 732
Table 15 Mix Design of LWC-SINTAGG
5.1.2 Lightweight Concrete with LECA Lightweight Aggregates
Predefined Parameters:
Bulk density of LECA: 320.624 kg/m3
Water Absorption of LECA: 18% Specific Gravity Factor for LECA: 0.625
Fineness Modulus of fine aggregates: 3.0
Ordinary Portland Cement (Grade-53) conforming to IS Non-air entrained concrete is required
Lightweight concrete is required for a floor slab having 28-day compressive strength as
25 Mpa
Step1: Choice of Slump
As per Table 3.1 of ACI 211.2-98,
Maximum slump required for floor slabs is 75mm (3inches)
Step2: Choice of Nominal Maximum Size of Aggregate
Here, maximum size aggregates is 16mm
Step3: Estimation of Mixing Water & Air Content
As per Table 3.2 of ACI 211.2-98,
For maximum slump of 75mm, non air entrained concrete and maximum size of aggregates upto 19mm,
Mixing Water Content – 202 kg/m3
Step 4: Selection of Approximate W/C
As per Table 3.3 of ACI 211.2-98,
For target strength of 34.5 Mpa (5000 psi) & non air entrained concrete,
W/C – 0.48
Step 5: Calculation of Cement Content
Here, W/C = 0.48 & Water = 202 kg/m3
Therefore, 202/C = 0.48
Cement = 420 kg/m3
Step 6: Estimation of Lightweight Coarse Aggregate Content
As per Table 3.5 of ACI 211.2-98,
For fineness modulus of sand as 3.0 & max size of aggregates upto 19mm, Fraction of coarse aggregate per unit volume of concrete = 0.68
Volume of coarse aggregate per unit volume of concrete = 0.68 x 1 x 320.624
= 218 kg/m3
LECA (per m3 of concrete) = 218 kg/m3
Step 7: Estimation of Fine Aggregate Content
The quantity of fine aggregate is determined by difference.
As the value of specific gravity factor for LECA is 0.625, the estimation of unit weight of concrete cannot be made from Table 3.6 of ACI 211.2-98 because the values in the table only range from 1.0 to 2.0 of specific gravity factor
In such a case, as the code says the estimated unit weight of lightweight concrete can be made from experience or literature,
From the literature,
Estimated unit weight of lightweight concrete = 1425 kg/m3
Now, Water = 202 kg/m3
Cement = 420 kg/m3
Coarse Aggregate = 218 kg/m3
Total = 1425 kg/m3
Fine Aggregates = Total – (Water + Cement + Coarse Aggregate)
Fine Aggregates = 585 kg/m3
Mix Proportions (kg/m3) for LWC with LECA:
Water 202
Cement 420
Coarse Aggregates (SINTAGG) 218
Fine Aggregates (Sand) 585
Table 16 Mix Design of LWC-LECA
Mix design
Design Parameters
Max size of aggregate=20 mm
Workability =100 mm slump
Specific gravity of cement=3.15
Specific gravity of grog(kapachi)=2.4
Specific gravity of grog(grit)=2.35
Water absorption in coarse grog=13%
Target mean strength
Fck=25 N/m^2
F’ck=fck+1.65 S
F’ck=25+1.65*5
F’ck=31.6 N/m^2
Selection of w/c ratio
w/c ratio=0.48
for 20 mm aggregate =186 liter
this is for 50 mm slump
increase 3% water for every 25 mm slump
so increase 6%
=186+6*186/100
=197 liter
As super plasicizer is used , the water content can be reduced up to 20% and above.
Assume 25% reduction in water content due to super plasticizer.
So, actual water to be used =197*.75=148 litre
Calculation of cement content
w/c ratio=.48
water used=148 liter
cement content =148/.48
=308 kg/m^3
Fer severe condition max cement content is =320 kg/m^3
So, cement content=320 kg/m^3
Coarse aggregate and fine aggregate content
For water content of 0.5, the volume of coarse aggregate=.6
Our w/c ratio is 0.48 is near to .5
So, vol of coarse aggregate is=.6
And fine aggregate is=.4
Calculation of mix proportion
1.vol of concrete=1 m^3
2. vol. of cement= 320*1/3.15*1000=.1016 m^3
3. vol. of water=148*1/1*1000=.148 m^3
4.vol of chemical admixture @2.0 % by weight of cementious material
=6.4 *1/1.145*1000=.0056 m^3
Mass of chemical admixture=2*320/100==6.4kg /m^3
Absolute vol. of all the materials except total aggregate
=.1016+.148+.0056=.2552 m^3
So, absolute vol. of total aggregate = 1-.2552=.745 m^3
5.mass of C.A=.745*.6*2.4*1000=1072.8 kg
6.mass of F.A=.745*.4*2.35*1000=700.3 kg
Site correction
Absorption of fine aggregate=13%
=13*700.3/100=91.03 liter
Actual water=148+91.03=239.039 liter
Actual mass of fine aggregate=700.3-91.03=609.27 kg
Mix proportion
Water Cement F.A C.A
239.039 liter 320 kg 609.27 kg 1072.8 kg
.747 1 1.9 3.3525
5.2 Mix Design of Normal Concrete
Specific Gravity of Coarse Aggregates: 2.68
Maximum Size of Coarse Aggregates: 10mm
Specific Gravity of Fine Aggregates: 2.86
Fineness Modulus of Fine Aggregates: 3.0
Moisture Content of Fine Aggregates: 2.86%
Ordinary Portland Cement (Grade-53) conforming to IS Non-air entrained concrete is required
Concrete is required for a floor slab having 28-day compressive strength as 25 Mpa
Mix Design as per ‘IS 10262:2009 CONCRETE MIX PROPORTIONING – GUIDELINES’
Water 214
Cement 430
Coarse Aggregates 837
Fine Aggregates 967
Table 17 Mix Design of Normal Concrete
For the purpose of obtaining enhanced properties like workability and increase in strength following admixture has been used,
Name: Fair Flo Normal Super plasticiser
Manufacturer: Fair Mate
We are very thankful to Prof.xxx who guided us and helped us in every difficult situation we came across.
2017-4-20-1492714365