International Journal of Innovative and Emerging Research in Engineering Volume 4, Issue 3, 2017 Available online at www.ijiere.com International Journal of Innovative and Emerging Research in Engineering e-ISSN: 2394 - 3343 p-ISSN: 2394 - 5494 Experimental Study on the Strength and Durability of Nano- Concrete Prof. Pranay Lanjewar1, Anjali Jaiswal2, Ayushman Jain3, Bhagyesh Dhomne4, Dameshwari Thakre5, Parikshit Matale6, Ritesh Wankhede7 1Assistant professor, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 2Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 3 Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 4 Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 5 Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 6 Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] 7 Research scholar, M.I.E.T. Shahapur, Bhandara, Maharashtra, [email protected] ABSTRACT: Nanotechnology is one of the most active research areas which have wide applications in almost all the fields. As concrete is most usable material in construction industry it has been required to improve its quality. Improving concrete properties by addition of Nano-Silica have shown significant improvement than conventional concrete. Nano-Silica is used as a partial replacement for cement in the range of 1%, 1.5%, 2%, 3.5% and 4% for M₂₅ mix. This study summarizes the influence of nano-silica on strength and durability of M₂₅ grades of concrete with the used of nano-silica as a replacement of cement. Laboratory test were conducted to determine the compressive strength of nano-silica concrete at the age of 3 and 7 days. From this test it was found that the compressive strength of nano-concrete increases as compare to conventional concrete of M₂₅ grade. The replacement of cement with nano-silica more than 3.5% results in the reduction of compressive strength of nano- concrete. Key words: Conventional concrete, Nano-Silica (NS), Compressive strength, Durability. I. INTRODUCTION Nanotechnology is one of the most active research areas that include a number of disciplines including civil engineering and construction materials. Nanotechnology is the understanding, control, and restructuring of matter on the order of nanometers (i.e., less than 100 nm) to create materials with fundamentally new properties and functions. Concrete is the most common material used in the construction. It is composing material composed of coarse aggregate, finely powdered cement, fine aggregate and water with inherent physical, chemical, and mechanical properties. The use of nano-silica will create a new concrete mixture that will result in long lasting concrete structure in the future. Only a small percentage of cement can be replaced to achieve the desired results. These nanomaterials improve the strength and permeability of concrete by filling up the minute voids and pores in the microstructure. The use of nano-silica in concrete mix has shown results of increase in the compressive, tensile and flexural strength of concrete. Nano-silica mixed cement can generate nano-crystals of C-S-H gel after hydration. These nano-crystals accommodate in the micro pores of the cement concrete, hence improving the permeability and strength of concrete. Objectives The main objective of this project is to study the influence of nano-silica on the mechanical properties of high strength concrete. Nanotechnology can modify the molecular structure of the concrete material to improve the material properties. Effect of dosage of nano-silica on compressive strength of concrete. Comparative analysis of compressive strength of conventional concrete and nano-concrete with varying percentage of nano-silica. 170 International Journal of Innovative and Emerging Research in Engineering Volume 4, Issue 3, 2017 Why we used Nano-Silica Nano-SiO2 has been found to improve concrete workability and strength, to increase resistance to water penetration, and to help control the leaching of calcium, which is closely associated with various types of concrete degradation. Nano-SiO2, additionally, was shown to accelerate the hydration reactions of both C3S and an ash–cement mortar as a result of the large and highly reactive surface of the nano-particles. Nano-silica mixed cement can generate nano-crystals of C-S-H gel after hydration. These nano-crystals accommodate in the micro pores of the cement concrete, hence improving the permeability and strength of concrete. If silica present in excess quantity, the strength of cement increases but at the same time its setting time is prolonged. Nano-SiO2 was found to be more efficient in enhancing strength than silica fume. Even small percentage of nano-silica (0.5%) used in concrete was observed to increase the strength of concrete in 7 days. Nano-SiO2 not only behaved as a filler to improve the microstructure but also as an activator to promote pozzolonic reactions. II. MATERIAL USED The materials used to design the mix for M25 grade of concrete are cement, sand, coarse aggregate, water and Nano SiO2. A. Cement Ordinary Portland cement of 53 grades conforming to IS: 12269-1987 is used for preparing concrete specimens. The properties of cement used are given in the Table 1. Table-1: Properties of cement Sr.No. Characteristics Value 1 Specific gravity 3.15 2 Normal Consistency 30% 3 Setting Time a. Initial Setting Time 35 min b. Final Setting Time 180 min B. Fine Aggregate The fine aggregate was used in the experimentation were confirming to IS: 383-1970 specifications. Fine aggregate is the main component grading zone –II of IS: 383-1978 was used. Table-2: Properties of fine aggregate Sr.No. Characteristics Value 1 Fineness modulus 3.88 2 Specific gravity 2.75 3 Water absorption 1% C. Coarse Aggregate The coarse aggregate used in concrete is 12 mm size aggregate and tested as per IS: 383-1970 specifications. Table-3: Properties of coarse aggregate Sr.No. Characteristics Value 1 Fineness modulus 8.21 2 Specific gravity 2.82 3 Water absorption 0.8% D. Nano-SiO2 has been found to improve concrete workability and strength, to increase resistance to water penetration, and to help control the leaching of calcium, which is closely associated with various types of concrete degradation. 171 International Journal of Innovative and Emerging Research in Engineering Volume 4, Issue 3, 2017 Table-4: Properties of nano-silica [1] Sr.No. Characteristics Value 1 Physical state Powder 2 Particle size 5-40 nm 3 Specific gravity 1.3-1.32 III. METHODOLOGY The main objective of this project is to determine experimental investigation on behavior of nano-concrete with various percentages of nano-silica. The following steps are involved: Initially the raw material used for mix design of concrete are tested. As per the result of raw material, design M₂₅ grade of concrete by using Indian Standard specifications. Cube samples of size 0.15×0.15×0.15m are prepared for testing of compressive strength of conventional concrete for 3 and 7 days. Cube sample of nano-concrete are casted with varying percentage of nano-silica (1%, 2%, 2.5%, 3.5% & 4%) as replacement of cement. After curing of cubes for 3 and 7 days, compressive test are conducted using CTM. Also, durability of conventional concrete and nano-concrete is measured by finding % weight loss of 7 days. IV. EXPERIMENTAL WORKS Experimental program was designed to compare compressive strength and durability of concrete with M₂₅ grade of concrete and with replacement of ordinary Portland cement with nano-silica with various percentages (1%, 1.5%, 2%, 3.5% & 4%). The comparative study of mechanical properties of conventional and nano-concrete were studied with optimum nano-silica (4%) concrete. A. Mix Proportions Concrete mix is design to a compressive strength of M₂₅ grade with water cement ratio of 0.45. [2] Table-4: Proportion of materials Cement 438 Kg/m³ Fine aggregate 676 Kg/m³ Coarse aggregate 1179 Kg/m³ Water-cement ratio 0.45 C:FA:CA(by weight) 1:1.51:2.64 B. Preparation of Test Specimens For conducting compressive strength test on concrete cubes of size 150×150×150 mm are casted. After successful casting, the concrete specimens are de-moulded after 24 hours and immersed in water for 3 and 7days. Fig. shows some concrete specimen casted in laboratory. Figure: Casting of cubes C. Compressive strength [3] The compressive strength of concrete are determined after curing of 3, 7 and 28 days cubes and test results were obtained for various percentages nano-silica. 172 International Journal of Innovative and Emerging Research in Engineering Volume 4, Issue 3, 2017 Table-5: Compressive strength of conventional concrete and nano-silica cubes Specimen Compressive Compressive Compressive strength strength in 3 strength in 7 in 28days(N/mm²) days(N/mm²) days(N/mm²) CC 23.26 23.42 40.60 NS 1% 31.41 31.70 43.70 NS 1.5% 32.59 35.11 48.44 NS 2% 32.44 36.14 49.22 NS 3.5% 35.55 38.46 51.33 NS 4% 31.24 35.65 35.76 Compressive strength in 3 days(N/mm²) Compressive strength in 7 days(N/mm²) Compressive strength in 28days(N/mm²) Compressive strngth Specimen Graph:Compressive strength test D. Split tensile test results Determination of tensile strength of concrete is necessary to determine the load at which the concrete member may crack. Tests are conducted on casted cylinder at the age of 3, 7 & 28 days. Table:Split tensile test result Specimen Load taken at 28 days Splitting strength= 2P/(Π l d) (kN) in N/mm² CC 250 3.53 NS 1% 290 4.10 NS 1.5% 310 4.38 NS 2% 340 4.81 NS 3.5 % 365 5.16 NS 4% 330 4.66 Splitting strength= 2P/(Π l d) in N/mm² CC NS 1% NS 1.5% NS 2% Strength NS 3.5 % NS 4% Specimen Graph: Split tensile strength test 173 International Journal of Innovative and Emerging Research in Engineering Volume 4, Issue 3, 2017 E.