scholarly journals Influence of Calcined Bauxite Aggregate on the Resistance of Cement Composites Subjected to Small Caliber Deformable Projectile Impact

2021 ◽  
Vol 8 ◽  
Author(s):  
Fengling Zhang ◽  
Rui Zhong
Keyword(s):  
Experimental Investigation ◽  
Fine Aggregate ◽  
Cement Composites ◽  
Deformation Potential ◽  
Severe Damage ◽  
Depth Of Penetration ◽  
Crater Diameter ◽  
Projectile Impact ◽  
Crater Volume ◽  
Length Reduction

This paper presents an experimental investigation on the influence of calcined bauxite aggregate (CBA) on the resistance of cement composites subjected to small caliber deformable projectile impact at a designed velocity of 400 m/s. The deformable projectile was made from copper with a purity of 99.5% and a diameter of 8.0 mm. Compared to mixtures with conventional coarse granite aggregate and/or siliceous fine aggregate, the incorporation of either fine or coarse CBA or their combination is beneficial in reducing the depth of penetration (DOP), equivalent crater diameter (CD), and crater volume (CV) caused by deformable projectile impact. CBA is found to be more effective in controlling the DOP and CV in comparison to the CD. Replacing of conventional aggregate with CBA leads to more severe damage to the projectiles (e.g., projectile length reduction, diameter increase, and mass loss). Relative effective hardness is an effective indicator to the deformation potential and penetration capacity of a deformable projectile to impact cement composites incorporating CBA.

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

Experimental Study on Sand and Cement Replacement by Termite Mound Soil

2019 ◽  
pp. 279-287
Author(s):  
Harish R ◽  
Ramesh S ◽  
Tharani A ◽  
Mageshkumar P
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Compressive Strength ◽  
Natural Environment ◽  
Fine Aggregate ◽  
Test Results ◽  
Termite Mound ◽  
Cement Concrete ◽  
Cement Ratio ◽  
Compressive Strength Of Concrete

This paper presents the results of an experimental investigation of the compressive strength of concrete cubes containing termite mound soil. The specimens were cast using M20 grade of concrete. Two mix ratios for replacement of sand and cement are of 1:1.7:2.7 and 1:1.5:2.5 (cement: sand: aggregate) with water- cement ratio of 0.45 and varying combination of termite mound soil in equal amount ranging from 30% and 40% replacing fine aggregate (sand) and cement from 10%,15%,20% were used. A total of 27 cubes, 18 cylinders and 6 beams were cast by replacing fine aggregate, specimens were cured in water for 7,14 and 28 days. The test results showed that the compressive strength of the concrete cubes increases with age and decreases with increasing percentage replacement of cement and increases with increasing the replacement of sand with termite mound soil cured in water. The study concluded that termite mound cement concrete is adequate to use for construction purposes in natural environment.

scholarly journals Comparison of Conventional Concrete and Replacement of River Sand by Waste Foundry Sand and Cement by Nano-Silica

2020 ◽  
pp. 201-205
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Nano Silica ◽  
River Sand ◽  
Conventional Concrete ◽  
Foundry Sand ◽  
Concrete Production ◽  
Waste Foundry Sand

This paper presents an experimental investigation on the properties of concrete in which like cement is partially replacing by used nano silica and is partially replacing by used waste foundry sand. Because now a day the world wide consumption of sand as cement and as fine aggregate in concrete production is very high. Nano silica and waste foundry sand are major by product of casting industry and create land pollution. The cement will be replaced with nano silica and the river sand will be replaced with waste foundry sand (0%, 5%, 10%, 15%, 20%). This experimental investigation was done and found out that with the increase in the nano silica and waste foundry sand ratio. Compression test has been done to find out the compressive strength of concrete at the age of 7, 14, 21, and 28. Test result indicates in increasing compressive strength of plain concrete by inclusion of nano silica as a partial replacement of cement and waste foundry sand as a partial replacement of fine aggregate.

scholarly journals Experimental Investigation on Pouring Aggregate to Plug Horizontal Tunnel with Flow Water

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1763 ◽  
Author(s):  
Gailing Zhang ◽  
Shuang Hui ◽  
Weixin Li ◽  
Wanghua Sui
Keyword(s):  
Experimental Investigation ◽  
Critical Velocity ◽  
Water Flow ◽  
Gravitational Force ◽  
Coarse Aggregate ◽  
Solid Particles ◽  
Fine Aggregate ◽  
Mass Ratio ◽  
Range Analysis ◽  
Tunnel Model

This paper presents an experimental investigation on the main factors that influence the effects of pouring aggregate to plug a tunnel that has been inundated by groundwater to reduce the flow velocity. Moreover, a criterion for plugging the tunnel under infiltrating water to resist flow is proposed. A range analysis and analysis of variance both show that the influencing factors on the efficiency of plugging in descending order is the aggregate particle size, followed by initial velocity of the water flow, and then the water–solid mass ratio. The sedimentation process of the aggregate is likened to the deposition of solid particles into slurry in which the particles settle under gravitational force, thus accumulating at the bottom of the tunnel model due to the forces of the water flow and gravity. The critical velocity of the water that will transport the aggregate without settling can be used as a criterion to determine whether there has been a successful plug of the resistance to flow in the tunnel. The experimental results show that the critical velocity of fine aggregate is less than that of coarse aggregate, and the section with smaller sized aggregate or fine aggregate that resists water flow is flatter. In addition, the required minimum space between two pouring boreholes for a successful resistance to flow is discussed.

Influence of Different Types of Fine Aggregate on Cement Composites Resistance to High Temperatures

2014 ◽  
Vol 1000 ◽  
pp. 126-129 ◽  
Author(s):  
Tomáš Melichar ◽  
Jiří Bydžovský
Keyword(s):  
Mineralogical Composition ◽  
Mechanical Tests ◽  
Basic Material ◽  
Fine Aggregate ◽  
Cement Composites ◽  
Cement Mortars ◽  
Different Types ◽  
Natural Aggregates ◽  
The Impact

The paper discusses the impact of several selected aggregates on the basic material characteristics of cement composites. Both artificial and natural aggregates (four types in total) with different mineralogical composition were evaluated. The specimens were exposed to environments with the temperature up to 1000°C and then subjected to physico-mechanical tests. For the follow-up development of polymer-cement mortars, we selected two types of aggregates – fly ash aggloporite (FAA) and amphibolite (AMA).

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