2.2 Critique :-
From the past researches it is observed that the use of Alkali Resistant Glass fiber is implemented in concrete, but the use of Alkali Resistant Glass fiber concrete composites are quite small. It is reviewed that Alkali Resistant Glass fiber concrete causes less deterioration in the structure as compared to plain concrete, but the Alkali Resistant Glass fiber concrete improves the overall performance of the structure and also prevents the structure from the corrosion.
So in the present research work to improve the properties of RCC Precast Pipe composites some new techniques are implemented. Including steel bar reinforcement with Alkali Resistant Glass fiber are used to improve Quality.
2.3 Objectives of the study :-
The current investigation aims to study the behavior of Alkali Resistant Glass Fiber on Strength of Precast RCC Pipe mainly used in Underground Sewerage collecting Network / culverts .
The main properties of interest is comparison study between the conventional and Modified Alkali Resistant Glass Reinforced RCC Pipe regarding Strength, Crack control in Precast RCC pipes.
CHAPTER NO 3
PROBLEM FORMULATION AND METHODOLOGY
3
PROBLEM FORMULATION AND METHODOLOGY
3.1 Problem Formulation & Methodology –
Designing the Proposed Grade of concrete M35 as per IS-10262 :2009 and casting the Cube of different content Percentage of Alkali Resistant Glass Fiber with respect to weight of Concrete (e.g 0% , 0.25% , 0.50% , 0.75% & 1 %) and after testing the compressive strength & Flexural strength at 7 days and 28 (days with the help of accelerated curing tank) plot the graph for the Optimum Percentage of Alkali Resistant Glass Fiber content and At the Optimum Content Casting RCC pipe as per IS 458 :1982 specification of Precast RCC Pipe and Testing pipe and compare the conventional Precast RCC pipe & Modified Alkali Resistant Glass fiber Concrete pipe and compare the results.
3.2 Alkali Resistant Glass Fiber Reinforced concrete
Alkali Resistant Glass Fiber Reinforced concrete is a composite material made from combination of both concrete and Alkali Resistant Glass fiber which bonded together produce a composite with exceptional resistance to wear and tear. Glass reinforced concrete has relatively good strength and resistance to impact. When used in construction in developing countries, it can provide better resistance to fire, earthquake, and corrosion than traditional materials. It has been popular in developed countries because the technique can be learned relatively quickly.
3.3 Preparation of Glass fiber reinforced concrete :-
It includes two types of preparation Methods
• Spray up Glass Fiber reinforced Concrete.
• Pre mix Glass Fiber reinforced Concrete.
3.3.1 Spray up Glass Fiber reinforced Concrete:-
In the spray-up method, cement/sand mortar and chopped glass fibers are simultaneously pre-mixed and deposited from a spray gun onto a mold surface. The GFRC architectural panel industry sets an absolute minimum of four percent AR-glass fibers by weight of total mix as a mandatory quality control requirement. The spray-up process can be either manual or automated. Virtually any section shape can be sprayed or cast. This enables architects to design and manufacturers to produce aesthetically pleasing and useful component.
Fig 3.1 Photograph of Spray up Glass reinforced Concrete
3.3.2 Pre mix Glass Fiber reinforced Concrete:-
The premix process consists of mixing cement, sand, chopped glass fiber, water together into a mortar, using standard mixers, and casting with cast-molding, the mortar into a product.
Fig 3.2 Photograph of Pre mix Glass reinforced Concrete
3.3.3 Raw material test for Concrete:-
1) For Aggregate 10mm Size :- Method of Test as per IS:2386 (Part I)
Sr No. IS Sieve Size
(mm) Actual Wt. Retained (gm) Cumulative Wt. Retained (gm) Cumulative % Wt. Retained (gm) Percentage Passing
(%)
1 12.5 0 0 0.00 100
2 10 481 481 9.62 90.38
3 6.3 3850 4331 86.62 13.38
4 4.75 538 4869 97.38 2.62
5 2.36 103 4972 99.44 0.56
6 Pan 28 5000 100.00 0.00
Conclusion :-
Properties Result Method of Testing
Water Absorption (%) 0.64 IS:2386 (Part III)
Specific Gravity 2.73 IS:2386 (Part III)
Bulk Density 1.386 IS:2386 (Part III)
2) For Fine Aggregate :- Method of Test as per IS:2386 (Part III)
Sr No. IS Sieve Size
(mm) Actual Wt. Retained (gm) Cumulative Wt. Retained (gm) Cumulative % Wt. Retained (gm) Percentage Passing
(%)
1 4.75 105 105 10.50 89.50
2 2.36 72 177 17.70 82.30
3 1.18 110 287 28.70 71.30
4 600 mic. 350 637 63.70 36.30
5 300 mic. 240 877 87.70 12.30
6 150 mic. 86 963 96.30 3.70
7 75 mic. 17 980 98.00 2.00
8 Pan 20 1000 100.00 0.0
Conclusion :-
Properties Result Method of Testing
Zone II IS:383
Fineness Modulas 3.05 IS:383
Water Absorption (%) 1.30 IS:2386 (Part III)
Specific Gravity 2.55 IS:2386 (Part III)
Bulk Density 1.65 IS:2386 (Part III)
3) For Cemet :- Kamal cement SRC as Per IS:4031
Sr. No. Test Conducted Testing Result Requirement as Per IS:12330
1 Standard Consistency (%) 28.50 28 – 32
2 Fineness (%) 3.0 10 (Max.)
3 Initial Setting time (minutes) 185 30 (Min)
4 Final Setting time (minutes) 220 600 (Max.)
4) Mix Design:- M-35 Grade of concrete
Grade Designation M-35
Type of cement SRC
Maximum size of Aggregate 10 mm
Workability 40mm Slump
Exposure condition Very sever
Method of Concrete Placing Manual
Degree of supervision Good
Test data for Material:-
Cement Used Kamal SRC
Specific Gravity of cement 3.15
Specific Gravity of Coarse Aggregate-10 mm 2.79
Specific Gravity of Fine Aggregate 2.55
Water Absorption of Coarse Aggregate10mm 0.64%
Water Absorption of Fine Aggregate 1.34%
Target Mean strength of concrete : 43.25 N/mm2
Water Cement Ratio : 0.45
Cement Concrete Mix Proportion by volume : (1:1.35:2.37)
Slump :40 mm
Material Required Per Bag of cement :
1) Cement :50 Kg
2) Fine Aggregate :67.26 Kg
3) Coarse Aggregate (10mm) :118.20 Kg
4) Water :24.15 Kg
After complete the mix design we have decide the dosage (as 0%,0.25%,0.50% & 1%) for alkali resistant glass fiber in the concrete & tested for compressive & flexural strength at 7 days and 28 days with accelerated curing tank .
3.4 Casting of Concrete Cube & beam by pre mix method
The beam was prepared by using Compressive & flexural strength testing mould and use accelerated curing tank for testing. Some specifications for casting of beams are as follows,
• Beam size taken – 150mm*150mm*700mm
• Cube size taken – 150mm*150mm
• Mix proportion for concrete – (1:1.35:2.37) (For M35 grade concrete)
• Water: cement ratio (by mass) – 0.45
Fig 3.3: Casting of Glass fiber Reinforced Beam
Fig 3.4: Casting of Glass fiber Reinforced Cube
Casting the IS standard Concrete cube & Beam with alkali resistant Glass fiber and without containing the alkali resistant Glass fiber(By pre mix method) with different percentage to the weight, weight of concrete and mix the glass fiber properly uniformly distributed thoroughly throughout the concrete , so it is dispersed uniformly in concrete and working properly the fiber which have perpendicular to the loading causes more resistant and crack resistant compare to the fiber which was dispersed parallel to the loading then find the optimum percentage of Glass fiber (e.g 0% , 0.25% , 0.50% & 1.0% ) .Based on the above experimental investigation it is found that at 0.75 % of Alkali resistant glass fiber show optimum effect of glass fiber in Glass fiber reinforced concrete which is used in further for making the Alkali resistant glass fiber reinforced RCC Spun (Hume) pipe of different Diameter and observe the effect of glass fiber in RCC spun (Hume) pipe.
3.5 Accelerated curing tank.
The advantages of accelerated curing tank is that give the early 28 days compressive strength in 28 hours as per instruction given in IS code 9013 : 1978 as well as also give the 28 days flexural strength also in 28 hours as per instruction given in IRC 85 :1983. There are two methods to use the accelerated curing tank one is warm water method and another is boiling water method .In this research work we have use the boiling water method in acceleration curing tank to find out 28 days compressive and flexural strength within early 28 days. Accelerated curing tank test procedure as per IS 9013:1978 in which the casted specimens (cubes and beam ) kept in a humid environment (90% humidity and 27+2oC temperature for 23 hours + 15 minutes ) time counted from the time of addition of water into the other ingredients. Casted specimens gently and slowly lowered into the accelerated curing tank containing boiling water and kept in that condition for 3 ½ hours + 5 minutes. After this specimens removed from the boiling water in accelerated curing tank, then removed from the mould and cooled by put in curing pond in water (27+2oC temperature) for 2 hours. The specimens tested for compressive and flexural strength.
Fig 3.5: Accelerated Curing tank with specimen
3.6 Economics
Initially cost is high comparatively but overall advantage of Glass fiber concrete structures is that they are stronger and more durable than some traditional concret. Glass fiber reinforced concrete structures with critical complicated shape can be built quickly by spray up as well as premix process, which can have economic advantages but also time saving. In odd weather conditions, the ability to withstand and durable . Glass fiber reinforced concrete is used often because the constructions made from it also resistant to earthquakes. Earthquake resistance is dependent on good construction technique and additional reinforcement of the concrete.
3.7 Advantages
The advantages of a well built Glass fiber Reinforced concrete construction are the low weight, reduced maintenance costs and long lifetime in comparison with purely steel constructions. When a Glass fiber concrete is mechanically overloaded, it will tend to fold instead of break or crumble like stone or pottery. So it is not brittle. This is also durable and give well performance in acidic as well as alkaline condition. Much depends on techniques used in the construction.
(a) Its basic raw materials are readily available in most countries including alkali resistant glass fiber.
(b) The manufacturing process is very simple without use of any heavy or complicated equipment.
(c) It can be used in saline and alkaline areas very effectively due to alkali resistant glass fiber.
(d) This is very effective in the water logged areas to reduce the ground water table use as a porous pipes.
(e) The initial cost is high but its give better performance overall like strength and durability aspects.