scholarly journals Rebar properties in sand-substitute mortars after exposure to high temperatures

2021 ◽  
Vol 73 (04) ◽  
pp. 381-388
Keyword(s):  
Thermal Stress ◽  
Tension Test ◽  
Air Cooling ◽  
Test Results ◽  
River Sand ◽  
Manufactured Sand ◽  
Granite Powder ◽  
Cover Thickness ◽  
Cooling Methods ◽  
Strength And Ductility

This study investigates the effects of fire, cooling methods, and cover thickness, on the behaviour (strength and ductility) of 12-mm diameter rebars embedded in mortars with river sand (RS) substitutes such as granite powder and manufactured sand, with 30 and 50 mm cover thickness. Beyond 500°C, thermal stress induced random spalling of mortar cover, and tension test results showed strength decrement and ductility increment of rebars for air cooling, while the vice versa was observed for water quenching.

scholarly journals Mechanical and Durability Properties of Fibre Reinforced Concrete made with OPC, GGBS and Metakaolin

2019 ◽  
Vol 8 (10) ◽  
pp. 3286-3290
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Industrial Wastes ◽  
Test Results ◽  
River Sand ◽  
Manufactured Sand ◽  
Durability Properties ◽  
Strength Tests ◽  
Massive Scale ◽  
Strength And Durability

Concrete is a globally utilized material in the construction field. In the last few decades, Concrete consumption has become multifold and usage has enhanced in massive scale due to the rapid growth of infra sector. Generally, Concrete consists of cement, aggregate, and water; these ingredients become more expensive day by day and additionally hard to please and is increasing widely. During the process of making Ordinary Portland Cement(OPC) produces a large amount of greenhouse gases and the environment being polluted. To minimize the cement utilization and environmental issues is essential to switch the cement by another alternate materials such as pozzolanas. The various number of pozzolanic materials comes from industrial wastes are Groundz Granulatedz Blastz furnacez Slagz (GGBS), xFlyqAsh (FA), zSilicazFume (SF), Metakaolin (MK) etc are utilized in concrete. Similarly, the availability of river sand is getting drained furthermore it turns out troublesome. In order to avoid this problem river sand is alter by zManufacturedkSand (M Sand). An attempt is made in the present investigation to study on properties of fiber reinforced concrete (qsteelu fibers @ 1% of binder) of M40 grade made with OPC, GGBS, MK and manufactured sand. In this study, OPC is replaced by GGBS and MK in different proportions. By casting requisite number of cubes, cylinders then zMechanical properties are determined such as fCompressivekstrength,sSplitdtensile strength tests and durability properties are determined by conducting Water absorption and Sorptivity tests. Test results are compared between controlled concrete and innovative concrete of M40 grade.It is observed that 30%(15%GGBS,15%MK) replacement is optimum for strength and durability criteria.

scholarly journals Behavior of RC Beam under Monotonic and Cyclic Loading using Waste Materials as Fine Aggregate

2019 ◽  
Vol 8 (6) ◽  
pp. 2021-2027
Keyword(s):  
Thermal Power ◽  
Bottom Ash ◽  
Reinforced Concrete Beam ◽  
Absorption Capacity ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Rc Beam ◽  
River Sand ◽  
Manufactured Sand ◽  
Granite Powder

Crusher sand or Manufactured sand (M-Sand) obtained from stone aggregate quarries is widely used as fine aggregate in concrete to avoid the depletion of natural river sand. To avoid air and land pollution due to direct dumping of wastes in open land area from granite processing industries and thermal power stations, the behavior of reinforced concrete beam without waste (RC beam) and with waste (RCW beam) materials like granite powder (10%) and bottom ash (10%) as combined partial replacement for M-Sand was carried out. The parameters like load carrying capacity, ductility, energy absorption capacity and stiffness degradation were evaluated. The behavior of all the parameters of both the beams was similar and there was slight decrease (10%) in strength parameters due to increase in fine pore particles. Hence, the granite powder and bottom ash can be used as partial replacement for fine aggregate in building constructions

scholarly journals An Experimental Programme on Frc with Opc, Flyash, Ggbs, and Metakaolin

2019 ◽  
Vol 8 (10) ◽  
pp. 3713-3717
Keyword(s):  
Fly Ash ◽  
Fiber Reinforced Concrete ◽  
Mineral Admixtures ◽  
Test Results ◽  
River Sand ◽  
Split Tensile Strength ◽  
Manufactured Sand ◽  
Granulated Blast Furnace Slag ◽  
Strength Tests ◽  
Lime Stone

The production of Ordinary Portland Cement (OPC) is increasing year by year world over. Further, the production of every tonne of OPC generates one tonne of green house gases, (CO2 ) which results in Global Warming. Usage of OPC is more in construction industry as it is a major ingredient in Concrete. As the usage of Concrete is increasing year by year, more and more is the OPC production and hence the environment is getting polluted; added to this undesirable scenario, the natural resources like lime stone used to manufacture cement and river sand are getting depleted year by year. In order to prevent the usage of large amounts of OPC in Concrete, mineral admixtures like Ground Granulated Blast furnace Slag (GGBS), Fly Ash and Metakaolin which are pozzolanic and cementitious in nature are adopted to replace certain percentages of OPC. Manufactured Sand (M-sand) is adopted to replace river sand. Experimental investigation is conducted on fiber reinforced concrete with steel fibers @1% of weight of binder by casting requisite number of cubes and cylinders of concrete of grade M25; in these mixes OPC is replaced with GGBS, Fly Ash and Metakaolin up to 45%. Mechanical properties are determined by conducting compressive strength and split tensile strength tests; additionally some of the durability properties are established by conducting Water absorption and Sorptivity tests. Test results are comparable between controlled concrete and innovative concrete of present investigation.

Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures

2010 ◽  
Vol 168-170 ◽  
pp. 564-569
Author(s):  
Guang Lin Yuan ◽  
Jing Wei Zhang ◽  
Jian Wen Chen ◽  
Dan Yu Zhu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Heating Rate ◽  
High Strength Concrete ◽  
Heating Temperature ◽  
High Strength ◽  
Air Cooling ◽  
Test Results ◽  
Strength Deterioration ◽  
Residual Compressive Strength

This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.

The Reasonable Amount of Polypropylene Fiber on Low-Intensity Manufactured Sand Concrete in the Case of Fixed Powder Paste

2014 ◽  
Vol 1065-1069 ◽  
pp. 2005-2010
Author(s):  
Hao Lu ◽  
Gu Hua Li ◽  
Jia Wei Yang ◽  
Liang Zhang ◽  
Ze Jiang Sun ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Polypropylene Fiber ◽  
Particle Type ◽  
River Sand ◽  
Manufactured Sand ◽  
Low Intensity ◽  
Reasonable Amount

Compared with the river sand, manufactured sand’s particle type and gradation is relatively poor and the surface is mat .The manufactured sand also has a big effect on the workability of concrete. In this paper,the Equivalent powder paste’s volume of manufactured sand concrete was determined according to Mehta and Aitcin’s ideas for the preparation of HPC,at the same time,the equivalent powder paste volume is assumed as the cement paste volume in the experiment. The influence of polypropylene fiber on Manufactured sand concrete’s workability and Compressive strength were researched in the case of fixed powder paste .

scholarly journals Mechanical Properties of High Calcium Flyash- GGBFS Geopolymer Paste, Mortar and the Effect of Glass Fibre Mesh on the Strength of Geopolymer Mortar Tile

2020 ◽  
Vol 9 (6) ◽  
pp. 722-729
Keyword(s):  
Glass Fibre ◽  
Demolition Waste ◽  
River Sand ◽  
Manufactured Sand ◽  
Granulated Blast Furnace Slag ◽  
Fine Aggregates ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Fibre Mesh ◽  
Geopolymer Paste

In this paper, a combination of high-calcium fly ash (HCFA) and ground granulated blast furnace slag (GGBFS) was used along with a combination of sodium hydroxide (NaOH) and sodium silicate(Na2SiO3 ) as alkaline activators (AAs) to produce geopolymer paste and mortar. The alkaline activator ratio (AAR) was maintained at 1.5 apart from their molarity at 10 for the study. A rational method, namely minimum voids approach was used for the mix design. A commercially available glass fibre mesh was used as reinforcement in the geopolymer mortar produced above, to assess its potential for use as a flooring tile. The influence of W/S (water-to-solids) ratio and the influence of various fine aggregates, namely, river sand (R), manufactured sand (M) and construction demolition waste (D) on the various geopolymer system (GP) and on the strength characteristics, are highlighted. A maximum transverse strength (TS) of 6.25 N/mm2 could be attained by the geopolymer tile, using three layers of glass fibre mesh and GP mortar developed. The study indicates that a combination of FA and GGBFS helps us to attain substantial strength under ambient temperature in geopolymer mortar

Corrosion Resistance of Industrial Pure Titanium and its Alloys under High Temperature and Different Cooling Methods

2021 ◽  
Vol 891 ◽  
pp. 3-9
Author(s):  
Cang Tian Wang ◽  
Qing Long Meng ◽  
Fang Hao Chen ◽  
Jing Hong Wang ◽  
You Ran Zhi ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Acid Corrosion ◽  
Pure Titanium ◽  
Corrosion Current ◽  
Chemical Equipment ◽  
Air Cooling ◽  
Water Cooling ◽  
Corrosion Condition ◽  
Impedance Technique ◽  
Cooling Methods

Industrial pure titanium (TA2) and Ti-6Al-4V (TC4) have been widely available for chemical equipment. However, the corrosion resistance changes during their post-fire performance. In this research, the electrochemical properties of industrial pure titanium and Ti-6Al-4V after heat treatment and different cooling methods were analyzed by AC impedance technique and dynamic polarization method. The results support two conclusions. Firstly, when the temperature is approximate to the phase transition point, for pure titanium and its alloys, water-cooling can obtain better corrosion resistance than air-cooling. With regard to pure titanium, its best corrosion resistance can be obtained at 800°C under water-cooling. For Ti-6Al-4V, its best corrosion resistance can be obtained when the temperature reached 910 °C under water cooling condition. Secondly, the corrosion current density under acid corrosion condition has risen compared with neutral corrosion condition. These results can provide some experimental data and theoretical basis for post-fire anticorrosion performance of titanium materials, and also support the safety, risk evaluation of titanium equipment.

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