Optimum Replacement Percentage Research Articles

Laboratory Studies on Strength Properties of Concrete using Fly Ash and GGBS

Abstract: Cement, fine aggregate, coarse aggregate, and water are the basic raw materials used in the manufacture of concrete. The naturally available aggregates are very precious and need to be conserved. Waste materials such as fly ash and Ground Granulated Blast Furnace Slag (GGBS) which cause disposal problems, and environmental problems can be economically used as a partial replacement for both fine and coarse aggregate. The present research focuses on conducting laboratory studies on the properties of M30 grade concrete by replacing fine and coarse aggregate with fly ash and GGBS. The results show that the optimum percentage of partial replacement of fly ash and GGBS is 30% for both fine and coarse aggregate. The compressive strength of concrete increased by 15% and 24%, respectively, and the tensile strength of concrete nearly increased by 20% in both cases. In addition, the use of waste material helps to reduce the cost of construction while simultaneously solving the disposal and environmental pollution problems.

An Experimental Study of Concrete Mixed with Coconut Shell as Partial Replacement of Course Aggregate

The high cost of conventional construction materials affects the economy of structure. The possibility of utilizing recycled coconut shell aggregates in concrete as coarse aggregate is examined in the present study. An optimum percentage replacement of coarse aggregate with coconut shell aggregate is determined from the study. Coconut shell is a lightweight material thus producing lightweight concrete. The replacement of coarse aggregate of coconut shell by 10%, 20% and 30%. The Design mix used is M20 grade and testing of specimens are conducted after 7 and 28 days of curing. The flexural and compressive strength of concrete are tests. The main objective is to encourage the use of these waste products as construction materials in low-cost housing Aggregate is a major ingredient for making concrete, occupying almost 70-80% part of concrete. Conventionally crushed rocks are used as coarse aggregate and river sand as fine aggregate. Both are naturally available materials. Due to the speedy growth of construction works, conventional aggregate sources are exhaust very fast leading to a significant increase in the cost of construction. For sustainable development, these materials should be used wisely and alternative materials need to be searched to replace regular aggregate. A large number of studies have been done to search for alternative materials for the production of concrete. At the same time due to fast industrialization, production of waste material is increasing day by day. Its disposal has become a real problem. It can be concluded that the ideal amount of coconut shell replacement for coarse aggregate for M20 Concrete is 10% -20%. Key Words: Concrete Mix, Coconut shell, Low cost housing, Flexural strength, Compressive strength, Design mix, Replacement of Course Aggregate.

Feasibility Study on the Use of Iron Ore Tailings as Fine Aggregate with Glass Fibre in Concrete

Concrete is the most widely used building material in the world, but its production has significant environmental consequences, including high carbon emissions and natural resource depletion. As a result, there is an increasing interest in the development of sustainable concrete technologies that reduce concrete’s environmental footprint while maintaining its performance and durability. Partially replacing fine aggregate with industrial waste is one such approach. It is a great practice for developing sustainable concrete that can help with environmental problems caused by the dumping of these waste materials at the same time maintaining the performance of concrete. It also provides economic and social benefits in addition to the environmental benefits. iron ore tailings is one such industrial waste that is the by-product of iron ore beneficiation process which has shown the potential for partial replacement of fine aggregate in concrete. In addition, glass fibre is added to improve the tensile property of concrete. A concrete mix of M20 grade were prepared by replacing fine aggregate with iron ore tailing at replacement level 15%, 25%, and 35% and the optimum replacement percentage was obtained. Further, glass fibre was added at the dosage of 0.5% by the weight of cement to the mix with optimised replacement of iron ore tailings and tests were conducted. This work also examines concrete’s physical, mechanical and durability properties with partial replacement of fine aggregate with iron ore tailings and glass fibre by conducting tests on strength and durability. Results obtained indicates incorporation of iron ore tailing with concrete reduces the workability of concrete, and the addition of glass fibre improved the compressive strength and split tensile strength. Durability tests show an increase in water absorption with the addition of iron ore tailings and a medium level of chloride penetration. The study showed the use of iron ore tailing as a sustainable alternative to fine aggregate in concrete.

Engineering experimental study on mechanical and durability properties of banana leaves ash as partial cement replacement in hollow concrete blocks

This engineering study investigates the mechanical properties and durability of Hollow Concrete Blocks (HCBs) made with banana leave-ash-replaced cement. This study focused on analyzing the physiochemical composition of banana leaf ashes (BLAs) and their impact on the mechanical and durability properties of these blocks. HCB production requires binding materials such as cement, and BLAs, a byproduct of agricultural waste containing Pozzolana, serve as an alternative. This study experimented with alternative mixtures to evaluate the influence of BLAs on the strength and durability of blocks, particularly their resistance to acid and sulfate attacks. The test was conducted by partial replacement of Dangote Ordinary Portland cement 42.5R with 0%, 5%, 10%, 15%, and 20% BLAs for Class “A,” “B” and “C” HCBs. The test results indicated that HCBs produced by BLAs can replace cement HCBs to achieve better strength and durability properties with respect to standards. Statistical results show that BLAs have a significant effect on the compressive strength of HCBs. Chemically acidic and sulfate-attack-resistant HCBs were examined, and the results showed that HCBs with BLAs had good resistance. The results of an experimental study on the mechanical and durability properties of BLAs blended with cement HCBs showed that replacing BLAs by up to 20% improves the durability and strength of blocks, resulting in better performance than the standards. The optimum percentage of partial replacement of BLAs with cement to produce HCBs is 20%.

Sustainable Concrete: Exploring Fresh, Mechanical, Durability, and Microstructural Properties with Recycled Fine Aggregates

The growing construction industry and global population have led to increased demand for concrete, resulting in increased waste production. Recycling construction and demolition (C&D) waste as recycled fine aggregates (RFA) in concrete could help reduce waste and conserve natural resources. This research delves into the meticulous examination of particle packing density within specific cylindrical volumes under standard compacting efforts, elucidating an order of compressive strength. The study comprehensively explores various concrete properties, including workability, compressive strength, flexural strength, split tensile strength, drying shrinkage, electrical resistivity, rapid chloride penetration, and microstructural characteristics (analyzed through XRD, SEM, and EDAX). RFA particles, ranging from 0.15 to 4.75 mm, were employed as partial replacements for fine aggregates, with replacement percentages varying from 0% to 100% in increments of 25%. The empirical findings underscore that the incorporation of RFA significantly enhances concrete properties. However, it was observed that surpassing the optimum replacement percentage of 25% (RFA 25) adversely impacts the concrete’s strength and microstructure. Specifically, RFA 25 exhibited remarkable improvements, with a 14.75% increase in compressive strength, a 6.61% boost in flexural strength, and a 13.14% enhancement in split tensile strength compared to conventional concrete (RC). Furthermore, RFA 25 demonstrated a 4.16% increment in drying shrinkage, 17.65% higher electrical resistivity, and an 18.83% superior resistance to chloride penetration compared to RC. The analysis of XRD, SEM, and EDAX results elucidated that at lower replacement percentages, the pozzolanic reaction enhances strength by forming additional hydration products. Conversely, at higher replacement levels, strength diminishes.

Compressive Strength of RAC Cylinders Cast with Recycled Aggregates from Different Structural Members

In this research study, the effect on the compressive strength of recycled aggregate members is presented. Demolished waste was collected from five different structural members. Hammering was used to reduce the aggregate size to a maximum of 1 inch. Using a 1:2:4 mix and 0.5 w/c ratio, 55 cylinders in 11 batches were prepared for each source of coarse aggregates. Additionally, one batch of cylinders was prepared with conventional concrete and its results were compared with the others. Altogether, 280 cylinders of standard size were prepared and cured for 28 days. The compressive strength of all specimens was determined in a universal testing machine. The optimum replacement percentage with the least reduction in compressive strength was found to be 35%. Column concrete contributed most to compressive strength with a reduction equal to 6.23%, whereas beam concrete caused a 6.9% reduction. Further, a comparison for mixed aggregates by taking the average of all sources was conducted. It showed that 35% replacement was also the optimum with a reduction in strength equal to 8.63%.

Durability studies on concrete with partial replacement of cement and coarse aggregate by seashell waste

A sea animal creates a hard, protective outer layer called a seashell. Empty seashells frequently wash ashore, and beachcombers find them. This marine byproduct can be used in concrete as a replacement for cement or aggregate. This study describes the use of seashell products as a partial substitute for cement and coarse aggregate in the production of sustainable concrete to evaluate the durability characteristic of concrete. Various percentages of seashell trash were substituted for the cement and coarse aggregate by weight of the concrete. Water absorption, sorptivity and rapid chloride permeability on the seashell concrete were performed experimentally. Additionally, sulphate and alkaline attack as marine environment were studied for seashell concrete specimens immersed in chemical solution for 90 days. The seashell concrete's durability traits were contrasted with those of a control specimen. It is concluded that the optimum percentage of replacement of cement and coarse aggregate by seashell powder (SP) and seashell aggregate (SA) are 10% and 20% respectively to obtain durable concrete.

Influence of Corn Cob Ash-Silica Fume Blend on the Mechanical and Durability Properties of Concrete

— This research explored the feasibility of corn cob ash-silica fume blend in the production of pozzolanic cement to produce High-Performance Concrete. The cement in concrete was partially replaced by corn cob ash-silica fume blend in 5,10,15 and 20% by weight of cement and was compared to a control mix of 0% replacement. An intelligent mix design, Densified Mix Design Algorithm (DMDA), was used to effectively reduce both water and cement content. In order to create high strength and workability, a polycarboxylate-based super plasticizing admixture was utilized in conjunction with a low water binder ratio of 0.35. Compressive strength was appraised to determine the mechanical properties at days 3,7,14,28 and 56 to determine the optimum percentage replacement and compared to the control at the specific ages. With the optimum percentage replacement, the flexural test was investigated at 28 days. Water absorption and electrical resistivity tests were also investigated as potential indicators of durability. All of the blends that included corn cob ash and silica fume produced a higher strength than the control except 15 and 20%, with 10% replacement yielding a cube strength of 61 MPa at day 56.

Mechanical and durability studies on fly ash based fibre reinforced concrete

The purpose of this study is to determine the fresh and hardened properties of fibre reinforced concrete along with durability properties with steel fibres (SF) and jute fibres (JF). This study presents properties of concrete prepared with Fly ash (FA) as a partial replacement to Ordinary Portland Cement along with the fibres. Concrete mix of M30 grade was prepared as per IS code guidelines. The specimens were prepared with 5, 10, 15 and 20 % Fly ash replacements along with 0.5, 1.0, 1.5 and 2.0 % Steel and Jute fibre replacements with respect to the binder. For comparison, control concrete mix corresponding to M30 grade was prepared with 0% FA and 0% fibres. Variation in workability with the addition of fibres was determined with the help of slump cone test. Various mechanical strength tests were conducted on the specimens to observe that the strength was enhanced due to addition of fibres. Ultra-sonic pulse velocity test was conducted to determine the strength of prepared specimens in non-destructive way and compared with destructive compression strength values. Durability tests - Carbonation, Acid attack, Sorptivity and Rapid chloride ion penetration tests were conducted to determine the optimum percentage of fibre replacement along with fly ash replacement for long term durability. According to the experimental results, adding 15% fly ash and 1.5% fibres enhanced the mechanical properties, whereas adding 10 and 15% fly ash, 1.5 and 2.0% fibres enhanced the durability properties in comparison with the properties of conventional concrete. This paves the way for developing sustainable alternatives in the construction industry by utilization of marginal materials such as fly ash and jute fibres.

Investigating the advantage of copper and steel slags as partial replacement material in a sand compaction column in stabilizing the soft clay

ABSTRACT The current study aims in finding the utilization of Industrial waste such as copper and steel slags as a partial replacement material for sand in Sand Compaction Pile (SCP) in proportions of 5%, 10%, 15%, 20%, 30%, and 40% by weight. From the direct shear tests, it is observed that the angle of internal friction increases from 27.59° to 40.1° and 34.82° for copper and steel slags, respectively. The tests are done by installing the SCP in a soft clay in California Bearing Ratio mould and it is tested under soaked and unsoaked conditions. The optimum percentage found from the study for both the slag material is 30%. Tests were also done by air-curing the composite soil within the mould for 7 days and water-curing the sample under soaked conditions for 4 days for the optimum replacement percentage.

Properties of Pervious Concrete Made with Ferrochrome Slag as a Coarse Aggregate

Ferrochrome slag (FCS) is produced during the production of ferrochrome alloy, which is an essential component of stainless steel. FCS has favorable physical and chemical properties for use as an aggregate in place of natural aggregate in the production of conventional and pervious concrete. Previous studies reported that the mechanical properties of concrete are enhanced when FCS is used in place of natural aggregates. This study evaluated the performance of pervious concrete containing FCS aggregates to replace the natural aggregates (NA) in various percentages (0%, 25%, 50%, 75% and 100% by weight). The effect of FCS replacement ratios on the mechanical properties (compressive strength, flexural strength, and split tensile strength), water permeability in terms of infiltration rate and density of the pervious concrete were determined. The results showed that the coefficient of water permeability increases with the increase of ferrochrome slag content. However, the compressive strength and density are reduced due to the increase of the porosity of the concrete. The optimum replacement percentage of natural aggregate with FCS aggregate was found to be 75%. The study concluded that it is possible to produce sustainable pervious concrete by using waste ferrochrome slag.

Mechanical, environmental, and economic assessment of sustainable cement mortar using Afghan natural pozzolan as a partial replacement for cement

Using natural pozzolan to produce cement-based mortar is one of the suitable solutions to reduce cost, energy consumption, and environmental impacts. In this experimental study, the paste replacement methodology (replacement of partial cement wt% with supplementary cementitious material) is used. Natural pozzolan, as vernacular material with high silicate aluminate originating in Afghanistan, is replaced (6, 13, and 20%) with cement in mortar. Various tests such as slump, compressive strength, tensile strength, water absorption, freezing-thawing cycles, relative length change, pull-off test, and microstructure analysis have been performed to study the properties of fresh and hardened mortar. The findings showed that the use of natural pozzolan containing a high level of silicate and aluminate as a replacement of cement in mortar improved 56 days compressive and tensile strength of mortar by 2.2 and 6%, respectively, water absorption was reduced by 1.6%, and the resistance to the freezing and thawing cycles was increased 10.7% as well compared to the reference samples. In addition, the results of economic analysis and sustainable development indicators assessment of mortar showed that using this replacement methodology was economically acceptable and reduced the potential of global warming and energy consumption by 13% of the production of one ton of cement using standard technology. The optimum replacement percentage was selected at 13% without compromising the mechanical properties of mortar.

Utilization of a mixture of waste plastic materials and granite particles as a partial replacement of coarse aggregate in concrete blocks

Due to an increase in population, there is a rapid rise in industrialization and urbanization in the country which marshalled the way for infrastructure development which has resulted in heavy usage of natural resources such as Fine Aggregates (Sand), Coarse Aggregates, etc. which are non-renewable. In this paper, we discuss about a method for reusing the plastic wastes and as well as safeguarding the natural aggregates by incorporating them into concrete. It aims at finding out the optimum percentage replacement for natural coarse aggregate with a mixture of plastic and granite pieces coarse aggregate, which can give us the same or more strength and has the same amount of workability as compared to nominal concrete. In this paper, we have worked on the M20 grade of concrete moulds/blocks. Tests were carried out on fine aggregates, high density waste plastics, coarse aggregates, cement, and plastic-granite coarse aggregate to determine their physical properties. Cubes of sizes 0.15 m × 0.15 m × 0.15 m were casted and were tested for 7-days & 28-days of compressive strength.

Enhancing strength properties by incorporating Fly ash for sustainable environment

The advancement of a country is well portrayed by its technological growth and its infrastructure. The architecture and infrastructure are two pillars of a growing nation. The raising buildings are paving way for the infrastructural growth. The foremost composition of a building is concrete, which holds cement, fine aggregate and coarse aggregate. The utilization of natural materials has been increasing as the construction work is increasing. The prolonged situation may lead to depletion of natural material. It has become evident that natural materials are the essential materials in binding concrete as well as filling the concrete. Many researchers have attempted on identifying an alternative for the natural materials utilized in making concrete. In this paper, Fly ash residue of coal is partially utilized as fine aggregate in the percentage of 10, 20, 30 and 40. Thereby the optimum percentage replacement has found to efficient and it does not affect the quality and the property of concrete. Fly ash use in concrete serves as a substitute for natural aggregate. Rather leaving the residue in the dumpsite, it has been utilized as a green concrete, thereby, promoting it towards sustainability. Durability is an important aspect in concrete when it comes to practical applicability to know whether the substitute material suits well for determined period of performance. The quality of various concrete mixtures was proved in additional investigations on the ultrasonic pulse velocity, and they complied with the requirements for a high-quality concrete. In order to assess the resistance to chloride ion intrusion in concrete, the rapid chloride permeability experiments were carried out after a curing period of 28-days. The test findings demonstrated that the performance of the concrete improved with the addition of fly ash.

Enhancement of shear strength of cohesionless granular soil using M-Sand dust waste

In recent times, shortage in the availability of river sand for construction activity has led to the production of Manufactured Sand (M-Sand) in huge quantities. This in turn has led to the production of huge volumes of M-Sand Dust Waste (MSDW) as a waste by-product which is disposed of nearby, in available open spaces and landfills. This leads to wastage of valuable land areas and also pollutes the air in surrounding areas leading to health hazards to the humans. An effort has been made in this project, to check the suitability of utilizing MSDW as a filling material in reinforced earth walls and to replace the conventional granular backfill materials with MSDW. As per IRC: SP: 102-2014, based on the particle gradation of MSDW, liquid limit, plastic limit test and direct shear test, it was observed that MSDW is suitable to be utilized as filling material in reinforced earth walls. Also, index properties of 3 types of granular backfill materials namely Silty Sand, M-Sand and River Sand were studied in this project and MSDW was used as a replacement to these granular soil in percentages of 20%, 40%, 60% and 80% by dry weight of soil. Based on the experimental results, it was concluded that ideal percentage replacement of Silty Sand and M-Sand with MSDW was found to be 20% for which maximum angle of internal friction (ϕ) was observed to be 43° and 49° respectively. Optimum percentage replacement of River Sand with MSDW was found to be 80% for which maximum ϕ value was observed to be 45° in comparison to 40° observed for River Sand without replacement.

Influence of Recycled Glass on Strength Development of Alkali-Activated High-Calcium Fly Ash Mortar

This article presents the development of green and sustainable mortars using alkali-activated high-calcium fly ash (AAFA) and recycled glass (RG) as part of the fine aggregate. RG was used to replace river sand at dosages of 0%, 25%, 50%, 75%, and 100% by weight. Sodium hydroxide (SH) and sodium silicate (SS) solutions were used as liquid alkaline activators in all mixtures. The AAFA samples were prepared with different liquid-to-binder ratios of 0.6 and 0.7, and the ratio of SS-to-SH was fixed at 2.0. Compressive and flexural strengths were determined at the ages of 7, 28, and 60 days. Test results showed that the compressive and flexural strengths of AAFA mortars declined as RG replacement increased; nevertheless, they increased with curing time. The high Na2O concentration derived from RG and the weak interfacial transition zone of RG are reasons for the decrease in strength development. The optimum percentage replacement of fine aggregates with RG was found at 25%. The 28-day compressive strength of AAFA with 25% RG was 32.5 MPa for L/B ratios of 0.6 and 29.5 MPa for L/B ratios of 0.7, which resulted in a strength index higher than 75% while releasing low CO2.

Strength, Porosity and Permeability Properties of Porous Concrete Made from Recycled Concrete Aggregates

Due to expansion in infrastructure and increased development of urbanization in Ethiopia, most of the places are covered either by impermeable cement concrete or bitumen that blocks the percolation of water from rainfall. A porous concrete made of zero fine aggregates, creating a pore that permits the concrete to be water permeable, is highly desirable. Similarly, the demand for natural coarse aggregates remains high, while natural resources are being depleted. Therefore, this study aims to investigate the properties of porous concrete using recycled concrete aggregate as a partial replacement for natural coarse aggregate. Experimental tests were conducted on cement setting time, workability of concrete, compressive, split tensile, porosity, and permeability of porous concrete. The properties of porous concrete at different ratios—0, 15, 30, 45 and 60%—revealed that RCA is suitable for use as coarse aggregate. The optimum replacement percentage of recycled aggregate for porous concrete in terms of strength is 30%, with 28th-day compressive strength of 17.37 MPa. However, slight increments were observed in porosity and permeability coefficient. Therefore, the concrete produced in this study is structural concrete, which is suitable for walkways and other concrete flat works, whereby heavy vehicle traffic loads do not exist.

An Experimental Study on Concrete with Partial Replacement of Cement By Rice Husk Ash and Bagasse Ash

Utilization of waste materials in concrete manufacture provides a satisfactory solution to some of environmental concerns and problems associated with waste management. Agro waste such as rice husk ash and bagasse ash were used as pozzolanic material for development of blended cement. The properties of concrete with partial replacement of cement by rice husk ash and bagasse ash for about 30% were investigated which includes its compressive strength, split tensile, flexural strength, durability property such as acid attack and sulphate attack. Among the various percentage replacement of cement by rice husk ash and bagasse ash, the strength test result shows that the optimum percentage replacement was about 70 : 20 : 10 (Cement : RHA : BA) which gives the optimum proportion of 30% replacement of cement with rice husk ash and bagasse ash to produce high performance concrete and contribute to sustainable construction. The cement in the concrete replaced by Bagasse Ash and Rice Husk Ash by the percentage of 5%, 10%, 15%, 20%, 25% and 30%. This optimum proportion result obtained is beneficial in improving the mechanical strength and durability property of the concrete. In this project work Conplast 340 Superplasticizer was used to improve the workability of concrete with replacement materials.

Strengthening of Recycled Coarse Aggregate using Different Surface Treatment Techniques

Numerous studies performed on recycled aggregate indicated that recycled aggregate has the undesirable characteristics of porosity, high water absorption, and low crush resistance due to the presence of porous mortar as well as the tiny seams derived from the crushing process. This study involves strengthening of RA using various surface treatment techniques like treatment with pozzolan slurry (fly ash, alccofine and cement slurry), HCl, polyvinyl alcohol and an optimized triple mixing method. The physical and mechanical properties of RA were comprehensively assessed before and after the surface treatment. The optimum percentage of replacement of natural coarse aggregate with treated recycled coarse aggregate is also found out based on compressive strength. It suggests that treatment using fly ash and cement pozzolan slurry is an efficient and feasible method for improving the mechanical properties of recycled coarse aggregate. This treatment of recycled coarse aggregate is not only an efficient way for enhancing the properties of recycled aggregate, but also an environmental friendly approach. Also the optimum percentage replacement of treated recycled aggregate was obtained as 60%.

Production of Low-Cost, High-Strength Concrete with Waste Glass as Fine Aggregates Replacement

The world of building materials is constantly and rapidly developing. New technologies are needed to reduce the cost of producing these materials and to ensure better efficiency when the materials are used in various engineering projects. One of these materials is high-strength concrete. This paper investigates the production of low-cost, high-strength concrete by partially replacing fine aggregates (FA) with waste glass sand (WGS). Four concrete mixes were considered in this study with varying percentages of WGS (0%, 25%, 50%, and 75%). For each mix, cubic, cylindrical, and beam specimens were cast to study the workability and different mechanical properties of concrete-like density, elasticity modulus, compressive strength, ultrasonic pulse velocity (UPV), split tensile strength, and flexural strength. In addition, the cost of each mix was calculated to evaluate the cost reduction efficiency of concrete with WGS compared to normal concrete. Results showed that the workability of concrete enhanced as the percentage of WGS increased. In terms of concrete mechanical properties, it was shown that the elasticity modulus, compressive strength, split tensile strength, and flexure strength for a concrete mix with 50% WGS as FA replacement was increased by 7%, 27%, 9%, and 50%, respectively. Also, it was concluded that the presence of WGS in concrete mixes reduced the production cost by up to 30% for a 75% replacement level. The authors recommended the usage of 50% WGS as the optimum replacement percentage for low-cost, high-strength concrete.