Total Volume Of Concrete Research Articles

Investigation the Properties of Waste Plastic Fiber Concrete Modified with HP-570 Super-Plasticizer

Recycling plastic waste has always been vital for sustainability, besides exploiting that waste to improve the mechanical properties of concrete mixtures which contribute effectively in the field of civil engineering applications. In this research, the enhancement of compressive, tensile and flexural strength of concrete mixtures was explored using both adding plastic fibers and HP-570 super-plasticizer. Plastic waste, as fibers, was mixed with an Ordinary Portland cement for a total volume of concrete of 0.5, 1, 1.5 and 2%, then the HP-570 super-plasticizer was added and the procedure was re-done. At the age of 28 days of curing, the compression strength was increased by (13.2%) while both tensile and flexural strengths were increased significantly by (117.4%) and (207.5%) respectively when using the plastic as fiber with 2%. Further improvement was gained by adding the HP-570 super-plasticizer for the concrete mixture.

Influence of carbon steel fibers on the flexural crack width of RC beam

Reinforced concrete beams are the significant structural elements in the structure. They improve resistivity against flexural loads. The concrete portion in the reinforced concrete beam is good in compression but at the time of bending reinforcement will take about the structural element. When the flexural stresses exceed the flexural capacity of the reinforced concrete beam cracks will occur at the flexural portion. In this investigation for avoiding and delaying flexural cracks, carbon steel fibres are incorporated into the concrete mix. The carbon steel fibres are added in concrete concerning the total volume of concrete. Different percentages like 0.5%, 1%, 1.5% and 2% of carbon steel fibres are added to the conventional concrete. Another side large amount of CO2 emission occurs while manufacturing the cement in the industry. Because of that the cement content is replaced 30% with GGBS (Ground Granulated Blast Furnace Slag). The mix design used in this investigation is M30 with a water-cement ratio of 0.4. Cubes, cylinders and RC beams of 1.5 m X 0.23 m X 0.23 m are cast and placed in curing for 7 days and 28 days respectively. In this investigation single crack and multiple crack behaviour is analysed. The compression and split tensile strength of concrete are enhanced by incorporating carbon steel fibres in the conventional concrete. The RC beams with 28 days effective curing were tested under the loading frame of 2000T capacity. The result shows the initial crack propagation time is increased by increasing fibres content because at the time of crack propagation fibers present in the concrete mix will resist the entry of crack in the concrete and crack width is reduced by increasing fibres content compared with conventional concrete.

Mechanical Properties of Concrete by using M- Sand and Basalt Fibre in Concrete

This paper presents the impact of the basalt fibre in concrete.Basalt fibre is a relatively new material and it is a high performance non-metallic fibre made from basalt rock melted at a high temperature. It is economical and having good strength characteristics, and also resists against temperature and alkaline environment. The Main aim of this paper is to find the compressive, flexural and split tensile strength of Concrete with M-sand and Basalt Fibre. The length of basalt fibre 12mm was used with in the range of 0.1% to 0.3%with total volume of concrete. Due to lack of river sand, it is partially replaced with M-sand by 50%and 60% in this work. This paper shows the enhancement of mechanical properties of concrete by adding Basalt fibre and partial replacement of river sand with M-sand.

Structural performance of composite panels made of profiled steel skins and foam rubberised concrete under axial compressive loads

This research investigates the feasibility of using rubber particles with lightweight foam concrete as an infill material in double-skinned profiled composite walls through experimental, finite element modelling (FEM), and analytical modelling. Two concrete mixes were used in the course of this study, namely, lightweight foam concrete (LFC) and lightweight foam rubberised concrete (LFRC) with rubber content of 8.5% by total volume of concrete. The two mixes had similar density of about 1584 kg/m3. Five profiled steel-concrete composite walls with 100 mm width, 550 mm length, and 600 mm height were tested under axial compressive loads. A digital image correlation (DIC) technique was used to measure and analyse strains and deformations of the profiled steel sheets and the results were compared with the results obtained from the strain gauges. FEM was conducted using ABAQUS software. An analytical model to predict the wall section capacity by considering concrete compressive strength and steel sheet buckling performance was developed. Finally, a parametric study based on FEM and the proposed analytical model was conducted to investigate the structural effect of different concrete strengths and/or steel sheet thicknesses. Although, LFRC had 20.1% lower strength than LFC, the experimental results showed that the average axial capacity of LFRC walls was reduced by only 16.8% with relatively less damage. The analytical and finite element modelling results agree well with experimental results.

Influence of rubber particles on the properties of foam concrete

This paper addresses the fresh and hardened properties of foam concrete incorporating crumb rubber from car tyre waste as partial replacement of concrete sand by volume. Different parameters including water/cement ratio, rubber content, and concrete density were investigated. Some fresh concrete properties such as density, flowability and consistency have been investigated. Different hardened concrete properties were investigated including compressive strength, tensile and flexural strengths, modulus of elasticity, damping ratio, impact resistance, and water absorption. Investigations into the effect of elevated temperature on the concrete strength was also carried out. The results of this study showed that foam rubberized concrete with compressive strength above 10 MPa and density below 1600 kg/m3 could be achieved by using 17% rubber content of total concrete volume, although a reduction in concrete compressive strength was observed. However, there was an increase in concrete splitting tensile and flexural strengths for mixes with rubber content up to 8.5% and 17% of total concrete volume, respectively. The elevated temperature showed a reduction on compressive strength of 3.3%, 14.8%, 29.4%, and 40.4% for mixes with 0%, 8.47%, 17%, and 47.8% total rubber content, respectively. The impact resistance and damping ratio also increased with increasing rubber content. The damping ratio increased by 21.1% and 17.3% for the mixes with 17% and 47.8% total rubber content, respectively, compared with that of the control mix without rubber.

Investigation of mechanical characteristics and specimen size effect of steel fibers reinforced concrete

Steel fiber reinforced concrete (SFRC) is a new construction material with good tensile strength, fracture toughness, and ductility. Although many aspects of SFRC have been investigated extensively, the size effects on structural strength of SFRC members remain largely preoccupant. This study investigates the size effect on flexural strength of SFRC beams under three-point bending tests. For this purpose, four mixtures were made: a concrete without fibers as control concrete, and concretes reinforced with 0.5, 1, and 1.5% of steel fibers (SFs) of total concrete volume. The experimental test results indicate that the addition of fibers, even small quantities reduces concrete workability that needs more superplasticizer added. Flexural and compressive strength are improved and crack opening is limited as the fiber content increases. SFs are more efficient in flexural strength and make SFRC more sensitive to the size effect. New relationships are presented which fit the data quite well and give an accurate correlation with the experimental results according to the size effect and the quantity of fibers present in concrete mix.

Experimental analysis on supplementary cementitious materials with Alkali Resistant glass fibers

In this work, cement is partially replaced by mineral admixtures like fly ash, ground granulated blast furnace slag (GGBS), silica fume and 0.5% Alkali Resistant (AR) glass fibers are added to the total volume of concrete. Mix design for M40 grade concrete was developed for different proportions 15%, 30%, 45% of cement and strength and durability properties are determined. Strength properties like compressive split tensile, bending for all the proportions is tested and optimum proportion was chosen for beam casting. From the results, it was concluded that 30% replacement of cement is optimum for concrete strength properties. Hence, two beams are casted with different cross sections 150 × 150 mm × 1500 mm, 230 × 230 mm × 1500 mm for 30% replacement of cement with Glass Fiber Concrete (GFC) and two beams are casted with concrete of M40 grade. Beams are tested under two point loading comparing flexural strength, load deflection curves and different types of failures in Glass Fiber Reinforced Beam (GFRB) with conventional beam. Durability test is also done by curing cubes in chemicals like with concentrations of 3.5% NaCl, 5% H2SO4, 3% MgSO4 solutions for 56 days and results are compared between blended and conventional concrete.

Punching shear resistance of supplementary cementitious concrete slab

This paper analyses the Punching shear resistance of RC slab using different mineral admixtures like Ground Granulated Blast Furnace (GGBS), Silica fume and Alkali resistant (AR) glass fibers. Here, silica fume and GGBS are partially replaced with cement at different proportions of 0, 10, 20, 30% and 0.5% of AR glass fibers are added to the total volume of concrete. Strength studies of Split tensile, Bending and Compressive strength done for M40 grade of concrete and compared to the control concrete. The optimum percentage obtained at 20% replacement of cement on these studies is used for designing of RC slab. RC specimen of (1000 × 1000 × 60 mm) of dimension was casted with optimum strength and subjected to single point loading with Discontinued on all the side conditions on loading frame. Cracking and deflection are analyzed experimentally. The loads, deflections and crack configurations of strengthened specimen were compared to the control specimen with same dimension to determine the behavior of slab.

Resistência ao cisalhamento direto do concreto reforçado com fibras de aço

O concreto convencional apresenta em seu comportamento mecânico baixas resistências à tração e ao cisalhamento quando comparadas com a resistência à compressão. Como forma de melhorar estas propriedades mecânicas, diversas pesquisas têm avaliado a combinação da matriz do concreto com fibras de aço, originando o compósito concreto reforçado com fibras de aço (CRFA), uma mistura heterogênea que visa unir de forma adequada as características de seus componentes e obter melhorias no comportamento mecânico do material, principalmente quando aplicado em estruturas. Este trabalho avalia o comportamento mecânico de peças de CRFA comparativamente ao concreto convencional. Para isto foi produzida uma mistura de concreto de referência, com resistência à compressão axial em torno de 40 MPa, na qual foram adicionadas fibras de aço retilíneas de 60 mm de comprimento, diâmetro de 0,75 mm e fator de forma igual a 80, com gancho nas extremidades, nas frações volumétricas de 0,5 e 1,0%, percentuais estes em relação ao volume total de concreto. Dezoito exemplares prismáticos de concreto (150mmx150mmx500mm) foram moldados e submetidos ao ensaio de cisalhamento direto até a ruptura, sendo avaliadas a tensão última e o deslocamento vertical do plano de cisalhamento. Os resultados demostraram uma redução da resistência à compressão axial devido à adição de fibras, porém, obteve ganhos na resistência à tração e ao cisalhamento e o aumento da tenacidade do concreto, evitando sua ruptura de forma brusca.

Behavior of r.c. Element with partial replacement of copper slag as a fine aggregate on the properties of concrete

In recent years, it is a fact that the quantity of good quality natural sand goes on draining. In most of the regions, river sands are abused, which results in severe environmental problems, river banks stability and the safety of bridges. The excessive transportation cost is the major impact for the river sands to be more expensive. In the total concrete volume, about 65 to 80% is occupied by the aggregates. These problems can be overcome by using slag instead of sands. Slag is a by-product which is made from metal industries like glass, ash plastics, etc as waste materials. These slags are a fine substitute and coarse aggregate to be cast in the concretes and mortarscompositions. In accordance, for replacing fine aggregate several research works are carried out and that solved by using copper slag. Replacing sand with copper slag of about 40% is proven by most of research as an efficient aggregate. Our research, industrial by-products are applied in order to increase the 40% copper slag. This composition will be a fine aggregate in concrete to 50%, 60%. In another way by using silica fume or marble dust in 10%, 20% and 30% it will be fine aggregate for the concretes

Concrete slab fragmentation after bullet impact: An experimental study

The response of nonreinforced concrete to high-speed flying fragments depends on many factors such as composition, geometry and boundary conditions of the obstacle. In this study, the authors verified experimentally a series of concrete slabs with various aggregate types and amounts of steel reinforcement. The material properties were previously developed and verified during the laboratory experiments with standard cubic specimens. Moreover, the main goal of this research was the verification of high-strength concrete plates using different kinds of aggregate, that is, traditional gravel, granite, basalt and amphibolite subjected to the military bullet impact. It is known that the aggregate filled about 70% of total concrete volume, and therefore, the properties of aggregate, like density, strength and surface will be the main factors influencing the concrete strength and further concrete resistance to projectiles. The research presented shows that the type and shape of aggregate determined the conditions of concrete failure. The outcomes show that the obtained compressive strength varied between 60 and 80 MPa. In the second stage of the test, randomly distributed reinforcement was added to selected concrete mixtures. Hooked steel fibres with an aspect ratio of 50 in the amounts of 50 and 100 kg per cubic metre were applied. The influence of steel fibres on the concrete properties was verified in compressive and splitting strength tests. On the basis of preliminary laboratory tests, the final slab specimens, with the dimensions of 0.5 × 0.5 m and 0.05 m thickness, were produced. The final verification was performed in the real field conditions using the most popular military bullet, whose kinetic energy was more than 2000 J. The measurements of the initial and final velocities of the bullets and concrete fragments were obtained using high-speed camera measurement equipment. The final failure of the slabs was presented as the primary outcome.

Fracture Energy of Fibrous-Foamed Concrete Using V-Notched Beam Specimens

Foamed concrete has been widely used as an alternative material to ordinary concrete due to its advantages of low density and thermal conductivity. Moreover, this type of concrete has recently been used for structural applications. Many researchers have studied the properties of foamed concrete, including its flexural strength, compressive strength and Poisson’s ratio. However, studies on fracture energy are limited. In general, fracture energy of foamed concrete is influenced by several factors that are clearly not related to the strength of concrete itself. Therefore, further studies should be conducted on the fracture energy of foamed concrete. To enhance foamed concrete performance, various types of fibres (glass, polypropylene and steel) from 0% to 1.0% of the total volume of concrete were used as an additive material in this study. The density of the produced fibrous-foamed concrete was approximately 1600 kg/m3±50 kg/m3. The cube specimens were tested to determine compressive strength, and three-point bending test on notched beam specimens were conducted to obtain load–deflection profile. The fibrous-foamed concrete was categorised under a strength class of 10–17 MPa. The optimum strength is in the range of 0.4%– 0.6% fibre portions, thus indicating high fracture energy for Bazant and Committee Euro-International du Beton models. However, the fracture energy value of the Hillerborg model is increased when the portion of fibres is increased. Therefore, fracture energy increases directly with the increase of fibre portion. This relation was observed for all types of fibres.

Partial Replacement of Cement by Fly Ash & Rha and Natural Sand by Quarry Sand in Concrete

The use of rice husk ash as a by-product in the production of concrete can be considered as important for India since India is one of the leading rice cultivating country in the world. It also provides social aids related to problems associated with ash dumping in the environment. This husk consists of 75% organic volatile matter plus remaining 25% of the weight is converted into ash called as rice husk ash (RHA). This RHA contains majority of amorphous silica around 90%. In the present study,10% RHA is used as a cement replacement material. Proportion of sand is around 35% of total volume of concrete. Natural sand is mostly quarried from river beds that consist of higher percentage of inorganic materials, sulphates, clay, chlorides and silt which affect the durability, strength of concrete & steel thereby decreasing the life of structure. At least 30 % to 50% of Fine particles below 600 microns must be present for the production of good concrete. These particles are not present in river sand in necessary quantities. Also increase in digging may result in fall of ground level there by affecting the environment. So to fulfill the need of fine aggregate the simplest way is to use crushed natural stone i.e manufacturing sand. It produces the concrete of similar properties compared with concrete made with natural sand, such as compressive strength, tensile strength, modulus of rupture and degree of shrinkage. In the present study, various proportions have been considered such as 1. 30% Fine aggregate and 0% rice husk ash mix together in concrete by replacement of cement with the increase of RHA by 2.5% (gradually) and parallely decreasing FA by 2.5% (gradually) ,last proportion taken 22.5% FA and 7.5% RHA. 2. 70% cement, 22.5 % Fly ash & 7.5% RHA, partially replace natural sand by quarry sand i.e. 0% - 45% with an increase of 15% (gradually).The main purpose of the investigation is to obtain the optimum mix design and to examine the physical properties– density, strength (bending and compression), water absorption and moisture content.

Characteristic study on high performance hybrid fiber reinforced concrete using copper slag fine aggregate

This study focuses on the effect on the mechanical characteristics of high performance concrete upon the utilization of copper slag in order to replace the fine aggregate. Copper slag has chemical and mechanical characteristics that can make the material a probable and efficient replacement material to river sand in concrete. On the other hand extraction of the sand from river bed in excess quantity is hazardous to the environment. River sand was partially and fully replaced (100%) by Copper slag in various proportions in the concrete. The concrete is also added with fibres in order to improve its mechanical properties. The addition of micro steel, hooked steel and polyester fibres in hybrid form with 1.0-1.25% to the total volume of concrete is found to be beneficial to the concrete. From the test results the concrete with 50% of its fine aggregate replaced with copper slag shows the better results; improved performance in compressive, split tensile, flexural strength, toughness and ductility. The addition of micro steel and hooked steel in the concrete produced a concrete of lower water absorption percentage.

Strength improvement of recycled aggregate concrete through silicon rich char derived from organic waste

Abstract Recycled aggregates obtained from construction and demolition waste is known to have lower strength performance than natural aggregate concrete. Several studies have been conducted during the past decade to reduce the adverse effects of recycled aggregates on the strength properties of recycled aggregate concrete. The present study is in continuation of the similar approach, contributing towards the improvement of the recycled aggregate concrete properties with waste derived silicon rich char as a cement replacement from 0.1 to 0.75% of total volume of concrete. Concrete was produced with 100% recycled coarse aggregates and wash-mix sand. It was observed that rice husk and enhanced poultry litter char; both improved the compressive and splitting tensile strength at 0.1% of total volume. Rice husk char at 0.1% produced highest compressive and splitting tensile strength with 17% and 3% increment respectively. On the other hand, enhanced poultry litter and rice husk at 0.75% replacement produced optimum flexural strength than the rest of char mixes. Char was also found to reduce water absorption up to 0.5% of total volume and reduced the permeable voids in recycled aggregate concrete by creating dense structure. Based on the findings, we conclude that waste derived char can potentially enhance the properties of recycled aggregate concrete with marginal amount of cement content replacement while simultaneously acting as carbon storage.

MECHANICAL PROPERTIES OF WASTE PLASTIC BANNER FIBER REINFORCED CONCRETE

The objective of this research is to determine the mechanical properties of the waste-plastic-banner-fiber reinforced concrete: compressive strength, splitting tensile strength, rupture modulus and modulus of elasticity. Concrete mixtures with different proportions of waste plastic banner fiber were produced and tested: 0%, 0.25%, 0.5%, 1.0%, 2.0% of waste plastic banner fiber. The tests showed that the addition of fiber by 0.5% from the total concrete volume will increase the splitting tensile strength by 14.28% and produce the modulus of elasticity as high as 23,025 MPa (up to 12% from the normal mix) and yield the concrete compressive strength of 35.56 MPa (up to 4.95% of the normal mixture). The rupture modulus will increase by 4.11% as the addition of 0.25% of waste plastic banner fiber.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction ofribbed slab reduces concrete materials and thusthe cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab wastested underthree-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. Thisresearch showsthat SFRCRibbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.

Standardization the effect of shape of aggregates with respect to compressive strength of concrete

It is proved that aggregate’s types have the severe effect on physicomechanical properties of concrete as aggregate covered almost 70 to 80 percent of the total volume of concrete. The effect of Flaky and Elongated aggregates on strength, durability, and workability of concrete has often been qualitatively expressed. The aim of this work is establishing the same quantitatively. M25 grade concrete for different ratios of weights of Elongated to normal aggregate, Flaky to normal aggregate and combined Flaky & Elongated aggregate to normal aggregate was tested for compressive strength at 28 days concrete. Three different types of aggregates were employed in the investigation, namely; normal aggregate, Elongated aggregate, and Flaky aggregate. Density and water absorption also kept constant to identify the effects on properties of concrete only for differences in shape. Thirty-six concrete cylinder was cast at 28 days. Varying dosages of Normal aggregate (60%, 65%, 70%, 75%,80% 85%), flaky aggregate (40%, 35%, 30%, 25%, 20%, 15%), elongated aggregate (40%, 35%, 30%, 25%, 20%, 15%), by mixture volume and length of 12inch (304.8 mm) & diameter of 6inch (152.4 mm) cylinder were used to test. Compaction was done by temping rod. Concrete cylinder was tested at the age of 28 days of curing. This study proposed of mixing three different types of aggregate in concrete. Compressive strength of concrete was measured by the effect of three different shapes of aggregates of varying dosages.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.