Green Concrete

Decreasing our over-reliance on cement as an ingredient in the making of concrete due to its contribution to the CO 2 emissions has led to numerous researches been conducted to find suitable replacement for cement in concrete mixes. Materials like fly ash, ground granulated blast furnace slag, silica fume, rice husk ash and metakaolin among others have been identified as materials that can at the very least be used as a replacement for cement in concrete mix. These materials are referred to as supplementary cementitious materials (SCMs). This paper reviewed the work that has been done on the use of fly ash and rice husk ash as partial replacements for concrete, its chemical composition and its effect on the compressive strength of concrete. Charts, tables and figures were employed as tools to study the various chemical compounds of fly ash and rice husk ash. It was seen that depending on how the coal or rice husk was initially processed the percentage of some of the minor compounds like Sodium oxide (Na 2 O), Titanium oxide (TiO 2) and Phosphorus pentoxide (P 2 O 5) were sometimes very low or not recorded as part of the final product. The data on the compressive strength of concrete after fly ash and rice husk ash had been added in percentage increments of 0%, 10%, 20%, 30%, 40%, 50% and 0%, 5%, 7.5%, 10%, 12.5%, 15% respectively analysed over a minimum period of 7 days and a maximum period of 28 days found out that the optimal percentage partial replacement of fly ash and rice husk ash for a strong compressive concrete strength is 30% of fly ash and 7.5% of rice husk ash.

The disposal of using recycled aggregate in concrete production raises in the last two decades. Some Green concrete mixes were also prepared from a recycled aggregate. This paper presents a study of using porosity crushed ceramic aggregate (PCCA) as replacement of coarse aggregate in concrete production. The result indicated that PCCA can replace Coarse aggregate by different ratios.

Ceramic wall tiles are used as building material in the field of construction. Manufacturing of ceramic tiles require different raw material like clay, potash, dolomite, feldspar, talc and different chemicals like sodium silicate, sodium tripoly, phosphate (STPP) in ceramic production. The temperature in the kiln varies from 200.c to 1200.c.this variation of manufacturing; therefore there is a pozzolanic reactivity in such material.In ceramic industry about 5-10% production goes as waste in various processes while manufacturing (this waste percentage goes down if the technology is installed in new units.) this waste of ceramic industries dumped at nearby places resulting in environmental pollution causing effect to habitant and agricultural lands. Therefore using of ceramic waste powder in concrete would benefit in many ways in saving energy & protecting the environment. The cost of deposition of ceramic waste in landfills will be saved.Raw materials and natural resources will be replaced. Which indirectly helps for reducing the greenhouse gas(co2).there is a large amount of carbon dioxide released in the cement production. In this research study ceramic waste powder from ceramic wall tiles industry is used as replacement to cement in concrete in an incremental order like 0%, 10%.20%, 30%, 40%, 50% and 60% by weight of cement in concrete for M 25 grade.

Green concrete is a concrete that supports the content of CO2 emissions reductions by using waste industries as cement replacement. The waste industries that commonly can be used in green concrete mixture design are fly ash, blast furnace slag, silica fume, and rice husk ash. The present of supplementary cementitous material in green concrete mixture can increase both compressive strength and cement efficiency. The higher of cement efficiency, the higher compressive strength and the lower cement content will be. Densified Mixture Design Algorithm (DMDA) is a method that has been widely applied to concrete constructions in Taiwan. DMDA method can support the higher of cement efficiency in green concrete design. By using DMDA to create green concrete with supplementary cementitous material can increase the life of concrete and hence reduce life-cycle cost.

Waste rubber tyre is one of the most abundant environmental hazards all over the world. Because of the increase in auto mobile production, there is a requirement of proper disposal of huge amount of used rubber tyres. Due to the fact that the presented sites for waste dumping are quickly diminishing, many countries have already banned the protection of waste-tyre rubber in disposal areas. Hence, efforts are being made to determine the future use of waste-tyre rubber in construction technology. Scrap rubber is assumed to be a possible material for use in concrete technology. It is considered as an alternative to the natural aggregates, used as filler in concrete mixture. Owing to lower strength, the rubberized concrete is recommended for non-load bearing structures and structural members. Rubber aggregates in concrete are mechanically cut to the mandatory sizes. It was effortful and was difficult to handle at the initial stages. However, all these difficulties can be easily figured out if suitable technology and machinery are available for this specific usage.

Plastic have become an essential part of our modern life style, and the global plastic production has increased immensely during the past 50 years. Numerous waste materials are generated from manufacturing processes, service industries and municipal solid waste. This has contributed greatly to the production of plastic related waste research is being carried out on the utilizations of waste products in concrete. Such waste products include tires, plastic, glass, steel, E-waste. The use of waste products in concrete not only makes it economical but also helps in reducing disposal problems. The development of new construction materials using recycled plastic is important to both the construction and the plastic recycling industries. This paper presents a detailed review about waste and recycled waste, waste management options, E-waste and research published on the effect of recycled plastic on the fresh and hardened properties of concrete. The effect of recycled, E-waste and waste plastic on bulk density, air content, workability , compressive strength, tensile strength, surface tensile strength, modulus of elasticity, impact resistance, permeability and abrasion resistance is discussed in this paper.

The present study investigates the performance of self-compacting concrete (SCC) and self-compacting sand concrete (SCSC) incorporating recycled concrete fines and aggregate under different sulphate environments. Similar mixtures incorporating natural aggregates and natural pozzolana were also tested for comparison. Different sulphate attack regimes (i.e. fully submerged and immersion-drying cycles) were applied. Compressive strength development/degradation under sulphate attack was monitored for all tested mixtures. Results indicate that the use of recycled materials did not significantly affect the strength development with respect to mixtures with natural materials. Moreover, mixtures incorporating recycled concrete aggregate and fine recycled concrete exhibited a better sulphate resistance behaviour than those with natural aggregates and natural pozzolana. In conclusion, the quality of the used recycled materials is a key factor in producing green and sustainable self-compacting...

A Green Concrete is a revolutionary topic in the history of concrete industry. This was first invented in Denmark in the year 1998. Green concrete has nothing to do with color. It is a concept of thinking environment into concrete considering every aspect from raw materials manufacture over mixture design to structural design, construction, and service life.
Green concrete is very often also cheap to produce because for example, waste products are used as a partial substitute for cement, charges for the disposal of waste are avoided, energy consumption in production is lower, and durability is greater. Green concrete is a type of concrete which resembles the conventional concrete but the production or usage of such concrete requires minimum amount of energy and causes least harm to the environment. The CO2 emission related to concrete production, is between 0.1 and 0.22 t per tonne of produced concrete.
However, since the total amount of concrete produced is so vast the absolute figures for the environmental impact are quite significant, due to the large amounts of cement and concrete produced. Since concrete is the second most consumed entity after water it accounts for around 5% of the world’s total CO2 emission. The solution to this environmental problem is not to substitute concrete for other materials but to reduce the environmental impact of concrete and cement. The potential environmental benefit to society of being able to build with green concrete is huge. It is realistic to assume that technology can be developed, which can halve the CO2 emission related to concrete production. During the last few decades society has become aware of the deposit problems connected with residual products, and demands, restrictions and taxes have been imposed.
And as it is known that several residual products have properties suited for concrete production, there is a large potential in investigating the possible use of these for concrete production. Well-known residual products such as silica fume and fly ash may be mentioned. The concrete industry realized at an early stage that it is a good idea to be in front with regard to documenting the actual environmental aspects and working on improving the environment rather than being forced to deal with environmental aspects due to demands from authorities, customers and economic effects such as imposed taxes. Furthermore, some companies in concrete industry have recognized that reductions in production costs often go hand in hand with reductions in environmental impacts.  Thus, environmental aspects are not only interesting from an ideological point of view, but also from an economic aspect. Green concrete has manifold advantages over the conventional concrete. Since it uses the recycled aggregates and materials, it reduces the extra load in landfills and mitigates the wastage of aggregates. Thus, the net CO2 emission are reduced. The reuse of materials also contributes intensively to economy. Green concrete can be considered elemental to sustainable development since it is eco-friendly itself. Green concrete is being widely used in green building practices.

Plastic is one of the most important industrial materials whose use has increased tremendously and dramatically in recent years, as the use of this substance is increasing day by day. The reason for the increase in consumption of plastic is owing essentially to the advantages it possesses such as its light weight [1], durability, flexibility, low cost [2], low water absorption, stable dimensions, good resistance to chemicals except for alkalis [3]. This massive production and high consumption of plastics has led to the accumulation of solid waste, a large part of which is produced by domestic wastes [1]. As this waste is considered a real threat to the environment because it is not degradable and it occupies a large area of land fill. Another disadvantage of using it is that it causes obstruction of water drainage through the soil, which in turn leads to contamination of the soil with diseases caused by mosquitoes [4]. In addition, it negatively affects public health [1]. To overcome these problems, recycling plastic waste and using it in concrete can be an appropriate solution to preserve the environment [5]. Overall, there are many types of plastic waste used, but the most used type is polyethylene terephthalate (PET). Accordingly, PET is one of the most problematic plastic materials for the environment and the method of treating it through burning leads to the production of toxic gases that are harmful to human health [6]. Therefore, we see that many studies have trend towards making this material environmentally friendly by including it in concrete mixes. There are numerous studies

The concrete which incorporates wastes and is environment-friendly is called as green concrete. Green concrete is a revolutionary concept in the history of the construction industry. Concrete is an eco-friendly material and the overall impact on the environment per ton of concrete is limited. The paper focuses on the aspect of choosing a material for green concrete. It presents the feasibility of using fly ash, quarry dust, marble powder, plastic waste, and recycled concrete and masonry as aggregates in concrete. The use of fly ash and stone quarry dust in concrete contributes to a reduction in bad environmental repercussions. To avoid the pollution and reuse of waste material, the present study is carried out by completely replacing natural sand in concrete by stone quarry dust and undergoing strength and economical perspectives of concrete and especially in high-performance concrete.

"The sheet glass cutting industries producing waste glass material, which are not recycled at present and usually delivered to landfills for disposal. Using glass powder in concrete is an interesting possibility for economy on waste disposal sites and conservation of natural resources. Glass is unstable in the alkaline environment of concrete and could cause deleterious alkali-silica reaction problems.  This property has been used to advantage by grinding it into a fine glass powder (GLP) for incorporation into concrete as a pozzolanic material.  In laboratory experiments it can suppress the alkali-reactivity of coarser glass particles, as well as that of natural reactive aggregates. It undergoes beneficial pozzolonic reactions in the concrete and could replace up to 30% of cement in some concrete mixes with satisfactory strength development. Waste glass powder in appropriate proportion could be used to resist chemical attack. 
The aim of the project work is to use glass powder in the range of 5% to 40% as replacement of cement and concrete cube strength compared with conventional concrete cubes. In these work waste glasses is to be used so the cost will be comparatively low when compared with normal concrete.
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Concrete industry is one of the major sources of consuming high volume of natural resources. On the other hand, cement industry is a significant point source of carbon dioxide emissions due to the decomposition of raw material and burning fuel during the manufacturing process. As the demand for concrete is growing, one of the effective way to minimize the negative environmental impact of the industry is the use of waste and by-product materials as cement and aggregate replacement in concrete. In the current study, possibility of making structural lightweight aggregate concrete using large amounts of waste material was investigated. The waste materials comprised oil palm shell, which was used as coarse aggregate, and a high volume (50% and 70%) of type F fly ash, as cement replacement by mass. The mechanical properties, such as compressive strength in different curing conditions, splitting tensile and flexural strengths, as well as density, ultrasonic pulse velocity, water absorption, and drying shrinkage up to one year were investigated. All oil palm shell concretes containing high volume fly ash are found to have adequate strength for formwork removal. Oil palm shell concretes containing high volume fly ash had 46%e60% lower cement content compared to previous studies with a similar compressive strength. Although, using high volume fly ash in oil palm shell concrete significantly reduced short-term mechanical properties, however, the use of limestone powder significantly improved the compressive strength at early and later ages. Test results also showed that there is no significant difference between the drying shrinkage of oil palm shell concrete containing 50% fly ash and the control oil palm shell concrete.

Shrinkage characteristics of different alkali-activated fly ash-slag binders were evaluated. Utilization of higher-pH sodium silicate activator mitigated autogenous and drying shrinkage. Strength development and setting time properties of different binary binders were measured. Addition of larger amount of slag to binary binder led to a quicker set, higher strength and stiffness. Activating by higher-pH sodium silicate solution resulted in a slower setting, higher strength and stiffer matrix. a b s t r a c t This paper evaluates the effect of fly ash and slag proportions and the type of activating solution on shrinkage and strength development of alkali-activated binary fly ash-slag mixtures (mortar and paste), cured at room temperature. Three different volumetric ratios of slag/fly ash were considered: 10%, 15%, and 20%. Two activators with different pH and modulus, n = (SiO 2 /Na 2 O) mol were utilized. The liquid to solid volume ratio of all binders was maintained at 0.75. The results showed that while the addition of slag significantly shortens the time of setting (up to 178 min), and increases the compressive strength (up to 93%) and bulk modulus (up to 43%), it also results in higher autogenous shrinkage, but smaller mass loss during drying. Measured drying shrinkage of mixtures with various slag contents was similar, likely due to counteracting effects of binder stiffness and degree of saturation. Fly ash-slag binders activated at higher pH exhibited larger chemical shrinkage, but lower autogenous (up to 21%) and drying shrinkage (up to 47%) magnitude.

Construction industry is growing rapidly and new technologies have evolved very fast to cater different difficulties in the construction industry. Among all materials used in the construction industry concrete is main material for construction puposes. Billions of tons of naturally occurring materials are mined for the production of concrete which will leave a substantial mark on the environment. Nowadays recycling of waste and industrial by products gaining popularity to make concrete environment friendly material and the concrete can be called as Green Concrete. This review paper will give us a brief idea about as well as advantages and disadvantages about green concrete.

Green concrete is the latest development in the field of construction technology which offers a sustainable and eco-friendly solution as a building material. The cement used in conventional concrete is responsible for releasing high amount of carbon dioxide which is harmful for the environment. The concept of green concrete renders replacement of cement partially or fully by various materials which are either byproducts in the production process of other materials or recycled waste. In this paper we focuses on replacing a different percentage of the cement with pozzolanic materials and also replacing the coarse and fine aggregate with locally volcanic materials to produce an eco-friendly and sustainable concrete. Thus, Four trail mixes were casted for estimating the concrete materials and proportion, also fifteen mixes were casted with some variables . Two types of coarse aggregate were used (dolomite and volcanic rock) to show the effect of volcanic aggregate on concrete properties. Fly Ash was used with 10% replacement of the cement , Volcanic ash was used with ( 20 % to 80%) replacement of the cement , the water cementatious ratio equal 0.3, Super plasticizer (visocrete-3425) was used with constant ratio 1% of the cement. Ordinary Portland cement was used in all mixes with constant cement content equal 500 kg/m3. Slump test were prepared on concrete in its fresh phase, hardened concrete tests (compression strength, bond strength, and bending strength) were prepared to identify the mechanical properties of concrete, the results show that using volcanic ash as a replacement of the cement nearly does not affect the slump of concrete, but on the
other hand enhances the mechanical properties of concrete.

An experimental study was carried out to investigate the strength properties of concrete produced with iron filings as partial replacement for sand. Concrete specimens (cubes, cylinders and prisms) were cast and tested for compressive, split-tensile and flexural strengths at 0% (control mix), 10%, 20% and 30% replacement of sand by weight with iron filings after curing in water for 28 days. The results obtained showed that the compressive strength of concrete increased for the 10% and 20% replacement levels of sand with iron filings by 3.5% and 13.5% respectively while there was a decrease of 8% for the 30% replacement level. The split-tensile strength of concrete for the 10% and 20% replacement levels increased by 12.7% and 1% respectively and decreased marginally by 1.7% for the 30% replacement level when compared to the control mix. The flexural strength of concrete increased by 11.1% and 4.8% for the 10% and 20% replacement levels respectively while it decreased marginally by 1.6% for the 30% replacement level as compared to the control mix. An optimum of 10% and 20% replacement by weight of sand (fine aggregates) with iron filings in concrete mix is recommended for concrete production depending on the desirable property required in the concrete.

In this modern world, building structures have their own requirements in terms of design and durability. To satisfy this requirement of the structural integrity of each structure, modification of traditional cement concrete has become mandatory. plain concrete (PC) is a fragile material with low tensile strength and may crack under traction. Randomly distributed basalt fibers can bind these cracks and hinder their development. Copper smelting is an industrial by-product obtained during copper slag increase the workability of concrete. Green concrete is concrete which uses waste material as at least one of its components, which does not lead to environmental destruction or it has high performance and life cycle sustainability. This experimental work was conducted on concrete samples containing cut basalt fiber as replacement by weight of cement in concrete and copper slag as a partial replacement of a fine aggregate by copper slag at 10% 20%, 30%, 40% and 50% by weight. The standard cube measure the compressive strength after 7 days, 14 days and 28 days and water absorption test carried out to evaluate the properties for 28 days and durability test
carried out to evaluate properties at 28 and 56 days. Also cost compared to the control mixes of M25 grade.

Green concrete is an active area of research for being the need of the day. This research article presents a laboratory investigation for the determination of strength correction factor due to different height (H) to diameter (D) ratio of cylinders made by using green concrete. Green concrete is produced by using demolished waste as coarse aggregates in 50% proportion of total coarse aggregates. Standard H/D ratio ensures proper strength of the concrete being used; otherwise, strength correction will be required for quality check and control of the concrete. Therefore, this research work is aimed at developing the correction coefficients. To achieve this purpose, total 45 concrete cylinders in nine batches are prepared using 1:2:4 mix and 0.45 water-to-cement ratio. One batch of cylinders with H/D ratio equal to 2 is prepared using conventional coarse aggregates only. These cylinders are used as control specimens to compare the results of the proposed concrete. For the rest of the batches of cylinders, H/D ratio is varied from 2.0 to 0.6 with a decrement of 0.2. After casting, compacting and curing for 28-days in standard fashion, all the specimens are tested for compressive strength in a universal testing machine. From the obtained results, the corrections factors for the compressive strength are developed. These factors are used to correlate the compressive strength of non-standard H/D ratio cylinder to compressive strength of standard H/D ratio cylinder. The results obtained from this reserach are very helpful for quality control and strength inspection.

Green concrete is a concrete that supports the content of CO2 emissions reductions by
using waste industries as cement replacement. The waste industries that commonly can be used in
green concrete mixture design are fly ash, blast furnace slag, silica fume, and rice husk ash. The
present of supplementary cementitous material in green concrete mixture can increase both
compressive strength and cement efficiency. The higher of cement efficiency, the higher
compressive strength and the lower cement content will be. Densified Mixture Design Algorithm
(DMDA) is a method that has been widely applied to concrete constructions in Taiwan.
DMDA method can support the higher of cement efficiency in green concrete design. By using
DMDA to create green concrete with supplementary cementitous material can increase the life of
concrete and hence reduce life-cycle cost.

In the current field, infrastructure development holds the key to the growth of every nation. Concrete is one of the most utilized material by the construction industry which is a uniform material prepared of varied materials like sand, Cement, &aggregate. Though rapid urbanization has created a vast insist for natural sand hence made it even more costly. This lead researchers to find other materials which could be used as an alternate of sand whose main chemical composition is Silica Researchers found that materials like Copper Slag, Coal Fly Ash, Carbonate & Sand Stone dust etc. having silica composition could be used as a replacement of fine aggregate. In recent years, the concrete construction industry has seen a growing interest in the advantages
offered by fiber reinforcement. Different types of fibers available, basalt fiber is measured as a new material equipped for use It has an extremely good personality and high resistance to the thermal resistance of an alkaline environment and is a low price product, which makes it an excellent material for reinforced concrete Considering the implications of basalt fibers for concrete and because different lengths and volumes of basalt fibers have a result in the mechanical properties of concrete, it is proposed to review the effect of using different basalt fiber lengths The mechanical properties of the revised concrete are the tensile strength, compressive strength, flexural strength, workability, mass, permeability unit. This paper reviewed on utilization of Basalt Fiber and Copper Slag in Green Concrete.

In this research article, we analyze the effect of curing methods on compressive strength of recycled aggregates concrete prepared with 50% replacement of natural coarse aggregates as well as coarse aggregates from demolishing waste. We prepare 30 standard size cubes in six batches. In all batches 1:2:4 mix with 0.45 water cement ratio is used. One batch of the cubes is casted with all conventional aggregates. Five curing methods, i.e., water, air, gunny bags, steam and waste water are used to cure the specimens for 28 days. Our compressive strength results show that curing by gunny bags gives better strength results and helps in strength improvement of the recycled aggregate concrete. It is further observed that the compressive strength of the proposed specimens with gunny bags increases by 1.67% in comparison with compressive strength of conventional concrete specimens. Our experimental study shows that the use of demolished waste as coarse aggregates in new concrete along with appropriate curing method has promising results in terms of compressive strength.

This investigation includes the use of glass wastes after recycling to produce High Strength Eco- Friendly Concrete. The glass waste was collected, crushed, and grinded for 10 minutes to produce a powder with fineness higher than that for cement of about 7340 cm2/gm. Many tests were conducted on this powder including, chemical analysis, pozzolanic activity index tests, and the remaining content on sieve of 45 microns. The results show that the glass waste powder considered as a natural Pozzolan class (N) according to ASTMC618. Many concrete mixes with different percentages of glass waste powder as a partial replacement to cement (10%, 15%, 20%, 25%, and 30%) were prepared. The properties of concrete (fresh density, compressive strength at 7, 28, 60, and 90 days age, and water absorption at 60 days age)were studied and compared with the results of the reference concrete mix (without glass powder). The compressive strength for concrete specimens with 10%, 15% glass powder content at 2...

This review paper aims to present fundamental aspects of geopolymer developments and science to emphasize their suitability for high-temperature exposure. Beginning with a comparison of the thermal properties of OPC and geopolymer, the analysis then investigates the character and occurrence of aggregates and supplementary phases. Characteristics essential for evaluating geopolymer thermal properties are thermal expansion, thermal conductivity, strength retention, explosive spalling along with microstructural characteristics such as phase stability, weight changes (dehydration/rehydration), morphology changes, and thermochemical properties were analyzed much in detail.

Concrete is the most common material used in the construction of civil engineering structures and the global demand for concrete is significantly increased due to infrastructure growth worldwide. The production of Portland cement which is the main ingredient of concrete is not only costly but energy intensive. It consumes approximately 7.8 GJ (Gigajoule) of energy per ton of cement production and also cement production process results in the emission of large amount of CO 2 , a greenhouse gas. To overcome these problems, there is need to find some replacement to some extent. Nowadays there is a solution to some extent and the solution is known as "Green" concrete. By the use of green concrete, it is possible to reduce the CO 2 emission in atmosphere towards eco-friendly construction technique. There is a much potential industrial waste product that has the potential to replace cement in concrete, however, fly ash is the industrial waste material that is discussed in depth in this particular paper. In this study, the potential use of siliceous/class F fly ash from power plant Kolaghat as a partial replacement of cement was studied. Firstly concrete mixes M30 is designed with two water-cement ratio 0.42 and 0.40 as per the Indian standard code (IS-10262:2009) by adding 25% of fly ash (Siliceous/Class-F) as a partial replacement of cement, without using any chemical admixture. Three concrete cubes of size 150 mm x 150 mm x 150 mm are cast for water-cement ratio 0.42 (Mix-A) and three concrete cubes of size 150 mm x 150mm x 150 mm are cast for water-cement ratio 0.40 (Mix-B) and tested for compressive strength at 28 days, 56 days and 90 days curing for all mixes. Based on the results high volume fly ash-based green concrete was made using siliceous fly ash. Concrete mixes M20 is designed with water-cement ratio 0.42 by adding 50% of fly ash (Siliceous/Class-F) as a partial replacement of cement, without using any chemical admixture. Six concrete cubes of size 150 mm x 150 mm x 150 mm are cast for water-cement ratio 0.42 (Mix-C) and tested for compressive strength at 28 days, 56 days and 90 days curing for all mixes. The analysis of result shows the promising values with respect to compressive strength as well as workability. Thus, green concrete may be used as a partial replacement of cement by means of fly ash as it is cheaper, because it uses waste products, saving energy consumption in the production. The result also shows that at initial stages strength gain is less for fly ash mixed green concrete and the strength is higher at later ages. Over and above all high volume fly ash mixed green concrete has greater strength and durability than the normal concrete.

An experimental study was carried out to investigate the strength properties of concrete produced with iron filings as partial replacement for sand. Concrete specimens (cubes, cylinders and prisms) were cast and tested for compressive, split-tensile and flexural strengths at 0% (control mix), 10%, 20% and 30% replacement of sand by weight with iron filings after curing in water for 28 days. The results obtained showed that the compressive strength of concrete increased for the 10% and 20% replacement levels of sand with iron filings by 3.5% and 13.5% respectively while there was a decrease of 8% for the 30% replacement level. The split-tensile strength of concrete for the 10% and 20% replacement levels increased by 12.7% and 1% respectively and decreased marginally by 1.7% for the 30% replacement level when compared to the control mix. The flexural strength of concrete increased by 11.1% and 4.8% for the 10% and 20% replacement levels respectively while it decreased marginally by 1.6% for the 30% replacement level as compared to the control mix. An optimum of 10% and 20% replacement by weight of sand (fine aggregates) with iron filings in concrete mix is recommended for concrete production depending on the desirable property required in the concrete. Original Research Article Olutoge et al.; BJAST, 18(3): xxx-xxx, 2016; Article no.BJAST.29938 2

Decreasing our over-reliance on cement as an ingredient in the making of concrete due to its contribution to the CO2 emissions has led to numerous researches been conducted to find suitable replacement for cement in concrete mixes.  Materials like fly ash, ground granulated blast furnace slag, silica fume, rice husk ash and metakaolin among others have been identified as materials that can at the very least be used as a replacement for cement in concrete mix. These materials are referred to as supplementary cementitious materials (SCMs). This paper reviewed the work that has been done on the use of fly ash and rice husk ash as partial replacements for concrete, its chemical composition and its effect on the compressive strength of concrete. Charts, tables and figures were employed as tools to study the various chemical compounds of fly ash and rice husk ash. It was seen that depending on how the coal or rice husk was initially processed the percentage of some of the minor compounds ...

Alkali activated fly ash (AAFA) is an alternative concrete binder that could serve as a substitute for ordinary Portland cement (OPC) for certain engineering applications. While this material has significant environmental and durability benefits, its potential volume instability and propensity to shrinkage and cracking could be of great concern. The subject of the present paper is evaluating the magnitude of drying shrinkage in AAFA binders of different compositions and at various ambient relative humidities (RH). Four AAFA paste mixtures were prepared using class F fly ash and liquid sodium silicate activators with various alkalinity (pH) and silicate modulus (n=(SiO2/Na2O)molar). The results were also compared with an OPC paste with a similar initial porosity. All AAFA pastes were steam cured at 60°C for 24 hours, followed by 6 days of moist curing at 23oC, while the OPC specimens were moist cured at 23oC for 7 days. The shrinkage specimens were dried under nitrogen purge at different relative humidities. The results show that activators with intermediate pH and modulus led to AAFA binders with higher compressive strength, denser pore structure, and larger drying shrinkage. Regardless of the activating solution, AAFA pastes dried quicker, and reached equilibrium faster than OPC paste. AAFA pastes also lost more moisture, but generally exhibited a lower drying shrinkage than OPC at similar RH. Steam curing of AAFA for a longer period (7-day vs. 1 day) stabilized the structure of AAFA binders and lowered the drying shrinkage.

Concrete is the most commonly used building material, in which cement and aggregate are unavoidable to manufacture. So, the use of excessive aggregate may lead to higher prices as a requirement of natural resources being costly. Solid waste management has nowadays received a lot of attention. From the ground. Different solid waste, like waste tyres, has become a concern due to its non-biologically degradable Nature. In many industries, such as thermal power plants, the majority of waste tyre rubbers are used as fuels, Cement furnaces, brick furnaces etc. Sadly, such use is not environmentally friendly and highly demanding, but it is costly. Thus, the use of scrap tyre rubber in the preparation of concrete was thought to be alternative disposal. This kind of waste is meant to protect the atmosphere. Attempt that has been done in this analysis to classify the different properties required for the construction of a concrete mix with rough tyre rubber particles to be used as aggregate in a systematic manner. As part of this project, the M20 grade concrete was selected as the reference concrete specimen. Rubber tyre particles in the shape of coarse aggregate is used in place of conventional coarse aggregate.

The concrete comprised of concrete wastes which is compatible with the environment, are called green concrete. Green Concrete created a revolution in the history of concrete industry. This Article covers all dimensions related to this field and shows that how green concrete materials can be selected. This Article also provides the simple function of product materials like: Fly ash, ore dust, Marble powders/ small grains, plastic waste, recycled concrete and cement. Using fly ash, assists decreasing greenhouse gas diffusion and its negative impacts on the environment. In addition the assessments show that in each ton of concrete 0.9 tons of CO2 is produced in each ton of Cement. Also, cement comprises 10 percent of total concrete weight. Therefore, most probably consuming green concrete causes the decrease in CO2 diffusion in the atmosphere. The above Article has been written in order to prevent pollution and reuse of the material. Green concrete is an organic material which is substituted to cement and it is highly affordable, because it has used waste products and conserves energy. Consequently, it is ideally produced. All green concretes have higher resistance and sustainability than a normal concrete.

In this modern world, building structures have their own requirements in terms of design and durability. To satisfy this requirement of the structural integrity of each structure, modification of traditional cement concrete has become mandatory. plain concrete (PC) is a fragile material with low tensile strength and may crack under traction. Randomly distributed basalt fibers can bind these cracks and hinder their development. Copper smelting is an industrial by-product obtained during copper slag increase the workability of concrete. Green concrete is concrete which uses waste material as at least one of its components, which does not lead to environmental destruction or it has high performance and life cycle sustainability. This experimental work was conducted on concrete samples containing cut basalt fiber as replacement by weight of cement in concrete and copper slag as a partial replacement of a fine aggregate by copper slag at 10% 20%, 30%, 40% and 50% by weight. The standard cube measure the compressive strength after 7 days, 14 days and 28 days and water absorption test and cost compared this to that of control mixes of M25 grade.

High Performance Concrete (HPC) prepared on the basic of eugenic considerations (cost-effectiveness and long life) is proposed to resolve real world concrete problems. Eugenic HPC was developed with the goal of preventing possible defects during the design and manufacturing stages using DMDA (Densified Mixture Design Algorithm). Durability is one of 5 parameters in eugenic HPC. Durability is emphasized on the strategy of physical dense and chemical strengthen concept. Concrete durability is so important for designing structural concrete of HPC to reduce the content of water and cement and also permeability. The decreasing of water and cement content will make the compactness of concrete be increased then the durability of HPC is improved. Binder in HPC is made by the combinations of cement and supplementary cementitious materials (SCM), such as blast furnace slag, fly ash, silica fume, and other fillers and the reaction between cement and any supplementary cementitious materials will create the durability characteristic of high performance concrete.

The residual RHA from Vietnam is used to test the likely application in cement and
concrete. The characteristics, quality and influence of RHA on the quality of concrete are investigated
in this investigation. The workability, strength and durability of concrete added with ground RHA
satisfy with the relevant standards and requirements. It indicates that the ground RHA in this study
can be used as a good supplementary cementious material. Therefore, it is possible to obtain RHA
concrete with comparable properties than those of the control specimen (without RHA) with a lower
consumption of cement, thus reducing the CO2 emissions during the production of cement and the
environmental and disposal problem of the ash can also be diminished. Moreover, while the results
will be able to substantiate the viability of application of RHA in concrete industry under the
prevailing conditions in Vietnam, they are also expected to be especially useful for future studies on
RHA in a specific condition in this country.

Recently, researchers have tried to find ways to reduce the negative effects of untreated coal wastes (UCW) on the ecosystem of the region. Recycling untreated coal wastes can however be identified as a practical solution in producing concrete aggregates. The present study investigates the mechanical properties of green concrete having untreated coal wastes. A total of eleven mix designs with different contents of untreated coal waste as aggregates were prepared and the cube, cylinder and prism compressive, tensile and flexural strengths as well as the elastic modulus of specimens were determined. The results revealed that untreated coal waste particles can potentially be reused in manufacturing concrete aggregates. It was also confirmed that selecting an appropriate amount of replacement can contribute to the property improvement of concrete, also suggesting an environmental solution to reducing untreated coal wastes. Therefore, replacing 5% of the aggregate with untreated coal wastes instead of sand and gravel, the mechanical properties increased. On average, in sand and gravel replacement compressive and flexural strength increased about 3–7% and 5–8%, respectively.

Concrete industry is one of the major sources of consuming high volume of natural resources. On the other hand, cement industry is a significant point source of carbon dioxide emissions due to the decomposition of raw material and burning fuel during the manufacturing process. As the demand for concrete is growing, one of the effective way to minimize the negative environmental impact of the industry is the use of waste and by-product materials as cement and aggregate replacement in concrete. In the current study, possibility of making structural lightweight aggregate concrete using large amounts of waste material was investigated. The waste materials comprised oil palm shell, which was used as coarse aggregate, and a high volume (50% and 70%) of type F fly ash, as cement replacement by mass. The mechanical properties, such as compressive strength in different curing conditions, splitting tensile and flexural strengths, as well as density, ultrasonic pulse velocity, water absorption, and drying shrinkage up to one year were investigated. All oil palm shell concretes containing high volume fly ash are found to have adequate strength for formwork removal. Oil palm shell concretes containing high volume fly ash had 46%e60% lower cement content compared to previous studies with a similar compressive strength. Although, using high volume fly ash in oil palm shell concrete significantly reduced short-term mechanical properties, however, the use of limestone powder significantly improved the compressive strength at early and later ages. Test results also showed that there is no significant difference between the drying shrinkage of oil palm shell concrete containing 50% fly ash and the control oil palm shell concrete.

Abstract Using glass powder to manufacture eco-friendly self-consolidating concrete (SCC) has been developed and improved in recent years. While researchers have determined the effect of glass powder on rheological properties of the green concretes, the sensitivity of SCC to this powder content yet remains to be investigated. This study introduced the concepts of insensitive design, and subsequently, the ranges of water to powder ratio, sodium lignosulfonate plasticizer (LS), and glass powder were determined and optimized by the artificial neural network and particle swarm optimization, respectively. The results showed the possibility of producing SCC with the least possible sensitivity to water, glass powder, and plasticizer variations. The best water to cement ratio to design an insensitive SCC derived between 0.33 and 0.34, but the reduction in the compressive strength was inevitable for the augmented water-to-cement ratio. The effect of glass powder on alkali-silica reactions (ASR) and compressive strength was also investigated to clear the way for the incorporation of glass powder in SCC. The results indicated that the ASR reduced to 52% by substituting 30% glass powder.

In this research paper, we analyze the effect of saw dust ash as cement replacement on compressive strength. Sawdust collected from wood workshops of Nawabshah city was converted into ash by burning and grinding. Six concrete mixes with ash dosage of 2.5% to 15% in the increment of 2.5% were developed. Also, a mix with conventional ingredients was developed as control mix. Workability by slump test shows a higher demand of water in the mix with sawdust ash, otherwise mechanical effort or admixtures will be needed to maintain the workability. Total 63 standard size cylinders were cast using 1:2:4 mix and 0.5 water cement ratio. In each mix, 9 cylinders were cast, out of which equal number of cylinders were cured for 7, 28 and 56 days. Weight of the specimen shows that sawdust ash is helpful in developing light weight concrete. Increased dosage of the waste ash produces lighter concrete. Comparison of compressive strength of the saw dust concrete mix with conventional concrete shows that 5% replacement of cement with the waste ash is the optimum dosage. At this dosage, the decrease in compressive strength is 11.66% and reduction in weight is about 2%. Although, the elongated curing shows improvement in strength results, but at optimum dosage the reduction in compressive strength up to 12% was recorded as compared to 28-day cured specimens.

Sustainability of the construction industry is taking a priority worldwide. The objective of this work is to evaluate the contribution of double using of waste clay brick and waste plastic for some properties of high volume metakaolin concrete. Waste brick powder (BP), after grinding, was blended with metakaolin (MK) at (50:50) % by weight, and this blended powder was replaced for ordinary Portland cement (OPC) at ratio (50:50) %. Six mixtures were produced, including one control mixture and five mixes that have a substitution 30% by volume of natural coarse aggregate with different ratios of blended waste clay brick aggregate (BA) and plastic aggregate (PL). The essential focus of the study is to observe density, compressive and splitting strengths of mixtures containing waste aggregate along with their workability in comparison with the control mix. The results showed that inclusion of blended wastes aggregate have adversely effect on the concrete workability, and decline the density at fresh and hardened state. Also, the use of wastes aggregate (blended or solely) has reduced the splitting strength. Moreover, compressive strength of control mix was 38.3 MPa, while mixes with waste aggregate have ranged between 32.9-42.4 MPa. It is, therefore, more beneficial to produce sustainable concrete with moderate strength for variety applications in the construction sector.

Self-compacting concrete (SCC) which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. The method for achieving self-compacting involves not only high deformability of paste or mortar, but also resistance to segregation between coarse aggregate and mortar when the concrete flows through the confined zone of reinforcing bars. Many concrete structure projects have been done in Taiwan using SCC by DMDA method, one of them is Nanggang project. DMDA method can create high density and high design strength with low water and cement content to achieve the high cement strength efficiency. With the water-to-cement ratio is higher than 0.42, water content is less than 160 kg/m3 and cement content is less than f’c/20, the stability of SCC’s volume can be controlled then the high physical density, high flowability and high homogeneity can be achieved. In 14 days after SCC making, the designed strength of 350 kgf/cm2 had been exceeded. High durability of SCC had been achieved in 365 days after making, with 4305 meter/seconds in ultrasonic test and 210 kΩ.cm in electrical resistivity.

With the ever-increasing industrialization and urbanization, huge amounts of natural resources are required to make concrete. Green concrete can provide a solution to reducing the negative impact of the concrete industry. This paper presents the results of experiments conducted to produce green structural lightweight concrete by using oil palm shell (OPS) as coarse aggregate, and ground granulated blast furnace slag (GGBFS) as a supplementary cementing material at 30%, 50% and 70% replacement of cement, and exposed to different curing conditions. Depending on the curing condition, test results show the possibility of producing green structural lightweight aggregate concrete with 28-day compressive strength of 23-42. MPa. The strength and density of GGBFS OPS concrete decrease as the percentage replacement of GGBFS increases. Data also show that initial hot water curing significantly improve the compressive strength of oil palm shell lightweight concrete containing high volume GGBFS ...