Properties Of Cement Concrete Research Articles

Effect of fly ash and nano Silica on the formation and evolution of Calcium Silicate Hydrate in Portland Cement during hydration process

Recently, the trend of replacing cement with mineral admixtures in concrete has witnessed increasing interest in the construction industry due to the reduction in embodied energy and CO2 emissions. However, the addition of these admixtures in Portland Cement (PC) affected the formation as well as the structure of the hydration product Calcium-Silicate-Hydrate (C-S-H), which is reflected in the mechanical and durability properties of cement concrete. In the present study, nano-silica (NS) and a mixture of fly ash (FA) and NS were replaced into PC (PC + 0.5 % NS, PC + 1 % NS, PC + 0.5 % NS + 20 % FA and PC + 1 % NS + 40 % FA) to systematically study the formation and structural evolution of hydration products, namely C-S-H, at atomic and micro-scales at the early stage of hydration (3 days) and a later stage of hydration (90 days). The formation and structure of C-S-H were analyzed to correlate the microstructure development by using XRD, Rietveld technique, FESEM, TEM, FTIR and nano-scale mechanical properties by employing the nanoindentation techniques. Atomic Pair Distribution Function (PDF) is used to understand the effect of admixtures on the C-S-H structure from atomic point of view. PDF shows the structural modification of C-S-H such as different polyhedral, separation of intralayer/interlayer, pair/bond length, coordination number of atoms corresponding to the addition of additives with hydration age. Also, porosity measurements show increasing or decreasing porosity during hydration with additives. It is observed that the contribution of low-density C-S-H (LD C-S-H) is greater than that of high-density C-S-H (HD C-S-H) in the beginning days, whereas HD C-S-H more than LD C-S-H in the latter days of hydration. The elastic modulus increased from 15.44 GPa to 19.82 GPa and the hardness decreased from 0.41 GPa to 0.35 GPa of LD C-S-H in early days, whereas elastic modulus decreased from 34.84 GPa to 29.33 GPa and the hardness increased from 0.75 GPa to 0.83 GPa of HD C-S-H in the latter stage due to addition of additives. However, both increased for LD C-S-H and HD C-S-H for each corresponding mixture during hydration. The present study reported the formation and microstructural modifications of C-S-H and the correlation with nano-mechanical properties due to addition of nano or micro-sized admixtures (nano silica and fly ash) in the cement system. This correlation helps to develop low-energy cement composites by tailoring cement systems with desired properties.

Mechanical Properties of Cement Concrete with Waste Rubber Powder

To investigate the mechanical properties of cement concrete incorporating waste rubber powder, the response surface methodology was employed. The Box–Behnken central composite design was applied to analyze the three primary factors influencing the road performance of cement concrete containing waste rubber powder: the water–cement ratio, sand ratio, and waste rubber powder content. The study determined the impact of these factors on the flexural strength of waste rubber powder cement concrete at both 7 and 28 days. Additionally, the effects of the water–cement ratio, sand ratio, and waste rubber powder content on the performance of cement concrete were analyzed. To investigate the impact of waste rubber powder on cement concrete, various mechanical property tests were conducted, including compressive, flexural, dynamic elastic modulus, and impact performance tests. Furthermore, the study explored the influence of waste rubber powder on the noise reduction capacity of cement concrete using both the rubber ball impact method and ultrasonic method. Lastly, the durability of cement concrete with added rubber powder was assessed through shrinkage tests, frost resistance tests, and chloride ion penetration tests.

Influence of Nano Silica On Properties of Cement Concrete

Influence of Nano Silica On Properties of Cement Concrete

Influence of corn cob ash additive on the structure and properties of cement concrete

In accordance with the Sustainable Development Goals (SDGs) concept, there is a need to find technologies that would help make concrete production less energy intensive and more environmentally friendly. One technology involves substituting some mineral components in concrete with rapidly renewable plant-based alternatives. This study aims to establish the essential patterns among the concrete composition, micro-structure, and properties of cementitious composites modified with corn waste. Additionally, it seeks to explore the potential for producing high-quality composites using this waste material. To assess the effectiveness of this kind of waste, the strength of the cement-sand mortar, several characteristics like compressive strength, flexural durability and water absorption of hardened concrete were studied. It is established that introducing corn cob ash (CCA) to substitute a part of the cement up to 16% is justified and allows to obtain mortar and concrete with enhanced properties. CCA has a beneficial impact on the properties of Cement Sand Mortar (CSM) when replacing cement by no more than 15%. The maximum effect was achieved at 10% CCA, and the rise of compressive and flexural strength were 6.06% and 6.32%. In concrete with a CCA amount of 8%, the most impressive growth of compressive strength was 7.14%, and the lowest value of water absorption, which is 10.31% lower compared to the ordinary composition. Including CCA reduces the properties like workability, density of concrete mixtures, and the hardened composite density. The scientific results obtained prove the possibility of using CCA as an effective mineral pozzolanic additive that improves the properties of concrete.

Influence of Sunflower Seed Husks Ash on the Structure Formation and Properties of Cement Concrete

The limitation of the application of non-renewable materials is one of the solutions to the problem of the sustainable evolution of civilization in the 21st century. Using additional binders in concrete obtained from plant waste will be economically and environmentally beneficial and will also allow us to move closer to achieving sustainable development goals. This study searches for rational composition components and a methodological approach regarding the technological characteristics to get the highest quality elements and prime concrete properties on the basis of sunflower seed husk ash (SSHA). Experimental concrete specimens were manufactured with partial Portland cement substitution with SSHA amounts ranging from 2% to 16% by weight in increments of 2%. This study focuses on investigating the density and workability of the concrete mixture, along with the compressive strength, concrete density, and water absorption. This article used granulometric, microscopic, and X-ray phase analysis methods. Including SSHA in all considered ranges reduces the slump in concrete mixtures. The optimal SSHA content in concrete is up to 12%. An 8% SSHA content has been found to deliver the most favorable mechanical characteristics of the concrete studied. The compressive strength of the investigated concrete has increased by 14.89%, and water absorption has decreased by 15.78%. Doi: 10.28991/CEJ-2024-010-05-08 Full Text: PDF

Improved conductive and self-sensing properties of cement concrete by PDMS/NCB-impregnated recycled fine aggregate

Polymer emulsion impregnation is a common method for strengthening recycled fine aggregate (RFA). By mixing Nano carbon black (NCB) into the polymer emulsion, highly conductive modified RFA (MRFA) can be simultaneously obtained. In this paper, highly conductive and self-sensing concrete was prepared by using the MRFA impregnated with the NCB and polydimethylsiloxane (PDMS) solution. The microstructure of MRFA and MRFA concrete physico-mechanical properties were studied. The effects of replacement ratio of MRFA, temperature, water content, and loading rate on the conductivity and self-sensing of prepared MRFA concrete was explored. The results show that the PDMS fills the pores of the RFA surface. The water absorption decreases by 2.53%, the apparent density and fineness modulus increased by 1.5% and 8.3%, respectively. With the increase of MRFA replacement ratio, the resistivity of concrete gradually decreases, and a sharp decline appears from 60% to 70%. The percolation threshold of concrete is calculated to be 3.37 vol% of NCB. Meanwhile, the MRFA concrete has good temperature sensitivity and humidity adaptability. Under the stress cycle loading, the stress sensitivity of the MRFA concrete with 70% replacement ratio MRFA is as high as 4.45%/MPa. Besides, the stress sensitivity of MRFA concrete decreases as the loading rate increases.

Review on Application of Lightweight Cenosphere in Construction Material

AbstractThere are many industrial waste products used in the construction industry like rice husk ash, fly ash phosphogypsum, marble powder, cenosphere, silica fume, copper slag, granulated blast furnace slag, etc. It is observed that the use of all waste materials is beneficial for improving the properties of cement concrete and also making a hunk of lightweight cement concrete. In that material, the cenosphere is the most economical material in the construction industry, so both waste materials are used in most of the experimental works. This review focuses on the concrete prepared by replacing cement and fine aggregate with the cenosphere at various percentages for the preparation of lightweight cement concrete. The usual way to use cenosphere is up to 30% replacement as fine aggregate or 20% replacement of cement gives good results. These reviews discuss the usability and extraction of cenosphere from fly ash, its properties, and applications. Also observed are the final optimum percentages for compressive strength, split tensile strength, and flexural strength for 7, 14, and 28 days.

Granite Crushing Screenings as a Component Factor in the Concrete Structure Formation. Part II: Experimental Studies of Structure-forming Potential

The paper considers the results of experimental studies of the individual and joint influence of macro-, meso- and micro-nanofractions of granite crushing screenings on the processes of structure formation and properties of cement concrete. It has been established that in the processes of formation of the structure of fine-grained concrete and the potential for resistance to its destruction, all fractions of stone crushing screenings perform their specific functions as a component factor. Macro-sized (crushed stone) grains of screening of the 5–10 mm fraction form a macro-scale frame of the addition system, which perceives force load with the accumulation of loading energy and braking of main cracks. Sand mesoparticles of fraction 0.16–5 mm fill the intergranular space of the system for adding macroparticles with dissipation of external loading energy in the matrix material. The microfraction of granite crushing screenings (the fraction is <0.16 mm), along with the effect of replacing the volume of cement stone, exhibits physical and chemical activity in the phase formation of hydrate compounds. It is shown that in the initial screening of granite crushing, the structure-forming role of its particles is not manifested effectively enough, the main reason for which is the “excess” of sand fractions, which push apart the grains of macrofractions and increase the water demand of the concrete mixture. Traditional methods of enriching screenings do not solve this problem. The principle of conditioning screenings by saturating them with macro- and micro-sized fractions is discussed. Based on this principle, a technology for mechanical processing of screenings has been developed to produce a “line” of products for targeted use in the building materials and products industry. The introduction of such technology will significantly increase the efficiency of construction and technological recycling of stone crushing screenings through maximum use of the structure-forming potential of their polydisperse composition.

АНАЛІЗ ДОЦІЛЬНОСТІ ЗАСТОСУВАННЯ КОНСТРУКЦІЙ ЖОРСТКОГО ДОРОЖНЬОГО ОДЯГУ ПІД ЧАС ВІДНОВЛЕННЯ АВТОМОБІЛЬНИХ ДОРІГ В УКРАЇНІ

Introduction. Road infrastructure is one of the key components of economic and social development of any country. Its rehabilitation is one of the important tasks of the post-war period, when roads can be damaged or destroyed. The article provides a comparative analysis of the use of rigid pavement during the restoration of roads in Ukraine in the postwar period. Problem Statement. Ensuring the reliability of road pavement. Purpose. To investigate the feasibility of using rigid pavement structures. Results. The feasibility of using rigid pavement is analyzed, the pavement designs are presented. The cost of materials is analyzed. Conclusions. A study of the advantages and disadvantages of using cement concrete in road construction was carried out, the calculation of rigid pavement was performed, the tentative mix design was selected, and laboratory tests of the physical and mechanical properties of cement concrete were carried out.

STUDYING THE PROPERTIES OF FINE-GRAINED CEMENT CONCRETE USING PLASTICIZERS AND BASALT FIBER

The article deals with the experimental and theoretical substantiation of the use of basalt fiber as a promising material that can be used to produce a new class of building materials. The nature of the dependence of cement concrete properties on the method of introducing heattreated fiber and the type of plasticizer is revealed. The most effective is the preliminary loosening of the fiber in the mixing water in the presence of a naphthalene-formaldehyde superplasticizer, followed by the introduction of the suspension into the molding mixture. Adsorption of the plasticizer on the surface of the fiber leads to hydrophilization of its surface, which contributes to the uniform distribution of the fiber throughout the mixture and, as a result, increases the strength of the concrete. The use of the naphthalene-formaldehyde additive SP-1 makes it possible to increase the compressive strength by 10% and the flexural strength by 21% compared to formulations based on the polycarboxylate plasticizer Sika Visco Crete. The compositions of fine-grained concrete using heat-treated basalt fiber have been developed, which make it possible to obtain materials with class B25...B60 in terms of compressive strength; Btb2.8...Btb6.0 in terms of bending strength; frost resistance not less than F300. The analysis of the microstructural features of fiber concrete with reinforcing basalt microfiber shows that the modified (heat-treated at 500 °C) fiber in the cement matrix performs its function due to changes in its surface properties. The fiber acts as a substrate for the active crystallization of clinker minerals, which helps to increase the adhesion of binder hydration products to the fiber. This is due to the increased alkali resistance compared to untreated fiber, and, consequently, its stability and strength in the aggressive environment of cement batter, as well as due to its relatively higher activity. These circumstances are obviously the main reasons for the increase in the flexural strength of composite materials (concretes) using the studied cement systems.

Study On Effect Of Marble Powder And Waste Foundry Sand As Fine Aggregates On The Properties Of Metakaolin-Cement Concrete

To bring an challenging and acceptable change in construction industry, upcoming graduates have to be much aware of alternate materials to be used in conventional concrete with improved performances and this study can be an encouraging approach to them. Many research studies have investigated the possible use of industrial by-products such as fly ash from thermal power plants, red mud from aluminium manufacturing industry, copper slag from copper smelting industry, GGBS from steel industry, and waste foundry sand from metal casting industries in cement concrete production. Here, it is investigated on the possibility of utilizing two industrial by-products in the production of concrete for achieving sustainable development. Metakaolin is used for replacing a specific percentage of cement, and waste marble powder and waste foundry sand are used to replace different percentages of conventional fine aggregates (sand) for producing a sustainable concrete. It is observed from the results that properties of cement concrete are influenced by the percentage content of metakaolin, waste marble powder and waste foundry sand.

Effect of coconut shell ash substitute with cement on the mechanical properties of cement concrete

The production of ordinary portland cement results in a great amount of carbon dioxide emissions, which has serious consequences for the environment. The building industry has been urged to make use of soil waste from industries or secondary materials in order to cut down on the amount of natural raw materials needed to make cement and concrete. Increases in population, economic activity, and social progress have all contributed to a rise in global garbage output. The investigation of waste reduction and reuse is one of the most alluring possibilities for handling such waste. It is becoming increasingly unaffordable to use cement in concrete works, despite the fact that the demand for homes and other constructions that rely on this material continues to rise in combination with the expansion of the human population; as a result, it is necessary to identify and develop alternative binding materials that can be used either wholly or partially in place of cement. In order to produce coconut shell ash (CSA), an agricultural waste material and environmental pollutant that is used as pozzolana in partial replacement of cement in the production of concrete, coconut shells are collected, burned in the open air (uncontrolled combustion) for three hours, and then incinerated in a muffle furnace at 800oC for seven hours. On the order of 0%, 5%, 10%, 15%, 20%, and 25% OPC was replaced with CSA in the concrete used to cast the specimens. Coconut shell ash is a viable cement replacement. The impact of CSA on mechanical qualities was investigated using a range of coconut shell ash replacements.

Review on effect of graphene oxide reinforcement on properties of cement concrete

The main drawback of producing concrete by traditional methods is the rise in carbon emission. Graphene has many remarkable features such as an eco-friendly concrete material, high elasticity; Elastic modulus (E) around 425GPa, tensile strength is around 1.3TPa so designated as 21st century material. This study investigates the effect of graphene oxide (GO) reinforcement to improve compressive and split tensile strength of concrete. The structure, TEM and AFM images of GO are studied. The GO was mixed at 0.01%, 0.02%, 0.03%, 0.04%, 0.06%, 0.08% and 0.1% by weight of cement in concrete for various studies. The effect of GO to improve the compressive strength and split tensile strength for M20, M25, M40, M60,M80 concrete grades is worked out. The average maximum rise in compressive strength and split tensile strength was found to be 24.3 % and 51.9% respectively. The highest rise in compressive strength of 34.08%, 46.3% was found to be for M25 grade similar proportion concrete and M25 fly ash concrete at 0.08%, 0.03% GO. The highest rise in split tensile strength of 45.6%, 189.2% was found to be for M40 fly ash, M80 fly ash GGBS concrete at 0.03% and 0.1% GO. From the study it can be concluded that use of GO in various grades of concrete is effective to enhance both compressive and split tensile strength of concrete. GO dosages like 0.03%, 0.08% and 0.1% proved to be optimum dosages in higher strength achievement.

Effect of paper sludge ash on properties of cement concrete: A review

Urbanisation and Industrialisation lead to high demand for cement, as cement concrete is the main constituent in construction. But the emission of CO2 during the production of cement leads to global warming. Also, the use of natural minerals to manufacture cement causes environmental degradation. Thus, to minimise cement production, an alternative source of cement is to be found. Paper sludge (PS) is a byproduct of the paper and pulp industry. A large mass of the sludge generated daily makes landfills uneconomical, as the sludge from paper mills is bulky. The waste that comes out of the industry acquires more and more space every year. Thus, to minimise environmental degradation, another trend is to be found. Due to the PSA's silica and magnesium concentration, which increases cement concrete's setting time, PSA (paper sludge ash) can be used as a cementitious material. A study reviewed the engineering properties of PSA as a cementitious material, which primarily focuses on how PSA affects the engineering parameters of cement concrete. The feasibility of PSA as a partial replacement for cement has been reported in various reviewed works, as PSA gives superior flexural and tensile strength. According tothe literature assessment, PSA can replace 5 to 10% of cement by weight; cement replacement with 15 to 20 % of PSA shows a decrease in the compressive strength of concrete. From the research paper, it has been found that the PSA is coarser in size, and less variation in the surface area was found at an early age. Due to finesse, PSA absorbs a large amount of water. Also, it has been observed that due to the calcination process, there is a decrease in the chemical properties. Therefore the calcination is done at 700 °C to 850 °C, which does not adversely affect the chemical properties of Paper sludge ash.

Effect of Addition of LD Slag Aggregate on Fresh and Hardened Properties of Cement Concrete

Cement concrete lends itself to a multitude of unique designs because of its many beneficial characteristics. Because of its inexpensive cost and desirable physical qualities, concrete is one of the most extensively utilised civil engineering materials. In this article, LD (Linz and Donawitz) slag is used to partially replace fine aggregate. This research mainly concentrates on partial replacement of natural fine aggregate with LD slag fine aggregate. Since the construction industry activity in India is gaining its momentum there is a scarcity of natural resources to overcome this problem substitute materials should be used to make the concrete and studies have to be conducted. In this study such an attempt is made where natural fine aggregate is partially replaced with LD slag fine aggregate. The purpose of this work is to investigate the fresh and hardened qualities of M-30 grade concrete in which LD slag has been partially replaced by the weight of natural fine aggregate in the ratios of 0%, 10%, 20%, 30%, 40%, and 50%. The slump test is used to investigate the features of workability. Compressive and split tensile strength tests are used to investigate the hardened characteristics of concrete. After 28 days of curing, the test is performed, and a mathematical regression model is constructed for the same.

Effect of volcanic pumice powder ash on the properties of cement concrete using response surface methodology

Effect of volcanic pumice powder ash on the properties of cement concrete using response surface methodology

Mechanical Strength and Thermal Properties of Cement Concrete Containing Waste Materials as Substitutes for Fine Aggregate.

The increasing volume of waste and the requirements of sustainable development are the reasons for the research on new waste management concepts. The research results presented in this paper show the effect of recycled aggregate on the selected properties of cement concrete. The aggregates obtained from three types of wastes are tested: recycled concrete paving, crushed ceramic bricks, and burnt sewage sludges. The recycled aggregates replaced 25% and 50% of the volume of the fine aggregate. The tested aggregates worsen the concrete mixes' consistency and decrease, to some extent, the compressive strength of the concrete. However, the tensile splitting strength of the concrete with recycled aggregates is similar to that of the reference concrete. Using recycled aggregates worsens the tightness of the concrete, which manifests itself by increasing water penetration depth. The thermal properties of concrete are slightly affected by the type and content of the recycled aggregate. Considering the expected improvement in recycled aggregate processing, they can be an alternative to natural aggregates. Using recycled aggregates in cement concrete requires extensive studies to search for ways to increase their possible content without worsening concrete performance.

Review on effect of graphene reinforcement on properties of cement concrete

Climate change has a negative impact on the mechanical characteristics of concrete in recent decades. The conventional concrete production contributed to carbon footprint on a large scale. Many researchers have started to investigate the new eco-friendly concrete materials. Graphene gives a number of excellent properties, such as high flexibility, Young’s modulus (E) = 1000000 N/mm2, tensile strength = 130000 N/mm2 and titled as material of the 21st century. This paper reviews the effect of graphene reinforcement to improve properties of cement concrete. The SEM images of graphene oxide (GO), reduced graphene oxide (rGO), graphene nanoplatelet (GNP) are studied with suitable preparation methods. The effect of these carbon based nanomaterials to improve the compressive strength and tensile strength of similar proportion concrete is worked out. The GO and rGO are proved to be effective in improving compressive strength and split tensile strength of concrete of similar mix proportion. The optimum dosage for GO lies in between 0.06 and 0.08 %, while for reduced graphene oxide (rGO) is 0.5 %, at which both strengths increase considerably. GNP does not contribute to increasing compressive strength and tensile strength of concrete but helps in pore structure enhancement. It reduces the mean, median, critical pore and void diameter effectively, which is designated as the nano-filler and segmentation effect of GNP.

A review on cement concrete strength incorporated with agricultural waste

The agricultural sector accounts for over 58% of the total GDP of India. Nearly 16% of India's GDP comes from this industry (GDP). India's agriculture industry has flourished because of the country's abundant arable land and variety of suitable growing environments. Studies show that agricultural waste material, when properly processed, possesses the pozzolanic properties which makes them suitable to be utilized as a partial substitute of cement content by weight in the production of cement concrete. In the present study, the availability and effect of agricultural wastes on the strength of cement concrete has been discussed and it was found that partial substitution of agricultural waste materials such as sugarcane bagasse ash, rice husk ash and palm oil fuel ash with cement content can reduce annual global consumption of cement by approximately 121 million tons, while maintaining the desirable properties of cement concrete.

Effects of cashew nutshell ash on the thermal and sustainability properties of cement concrete

The present study valorizes cashew nutshell ash (CNA) and uses it at 5–20 wt. % of cement for concrete production. The concrete grades of 25–40 MPa were used as mix design proportions. The thermal and mechanical properties of the concrete samples were determined on day 28 of curing. Regression models were used to predict the thermophysical properties of the concrete specimens. Also, the concrete's sustainability was estimated via the inventory of carbon and energy (ICE). The results revealed that CNA enhanced the thermal insulating characteristics of the concrete produced. Maximum compressive strength was obtained at 15 wt. % of CNA content, while the developed models yielded high precision. Compared with the control concrete, the sustainability index decreased as CNA content in the mix increased, indicating that incorporating CNA in concrete production improves the sustainability of such concrete. Therefore, the outcome of this work can be beneficial, especially in hot or arid climate regions, and at the same time, achieve a cleaner environment.