Comparisons of natural and recycled aggregate concretes prepared with the addition of different mineral admixtures (original) (raw)
Related papers
2018
In countries like India and elsewhere, the natural aggregate resources had already reached at alarming rate due to day by day high demand of construction activities in recent years. On the other hand, million tons of construction and demolition (C&D) residues and ceramic wastes are generated which are having hazardous effect on environment. These wastes can be utilized as a partial replacement of natural coarse aggregate in concrete and desired mechanical properties of recycled aggregate concrete can be achieved with the added use of mineral admixtures. Result shows that at 30% replacement level, compressive strength of recycled aggregate concrete is decreased by only 10% which is not significantly different than that of natural aggregate concrete and with 7.5% replacement of cement by Metakaolin can achieve the compressive and tensile strength of optimized recycled aggregate concretes same as that of Natural aggregate concrete.
Materials, 2022
The properties of cement concrete using waste materials—namely, recycled cement mortar, fly ash–slag, and recycled concrete aggregate—are presented. A treatment process for waste materials is proposed. Two research experiments were conducted. In the first, concretes were made with fly ash–slag mix (FAS) and recycled cement mortar (RCM) as additions. The most favorable content of the concrete additive in the form of RCM and FAS was determined experimentally, and their influence on the physical and mechanical properties of concrete was established. For this purpose, 10 test series were carried out according to the experimental plan. In the second study, concretes containing FAS–RCM and recycled concrete aggregate (RCA) as a 30% replacement of natural aggregate (NA) were prepared. The compressive strength, frost resistance, water absorption, volume density, thermal conductivity, and microstructure were researched. The test results show that the addition of FAS–RCM and RCA can produce c...
Influence of Mineral Admixture on to the Workability of Recycled Coarse Aggregate Concrete
In countries like India and elsewhere, the natural aggregate resources had already reached at alarming rate due to day by day high demand of construction activities in recent years. On the other hand, million tons of Construction and demolition wastes are generated which can be utilized as a partial replacement of natural coarse aggregate and desired mechanical properties of recycled aggregate concrete can be achieved with the use of mineral admixtures. AS individual properties of recycled C&D waste aggregate is different than that of natural aggregate, the use of such recycled aggregate will differ the workability property of concrete mix. Present study investigated the effect of recycled C&D waste aggregate (RA) and mineral admixtures Metakaolin on to the fresh properties of concrete. Results reveal that workability of concrete mix decreases with percentage increase of recycled C&D waste aggregate and decrease with the percentage increase of Metakaolin.
Mechanical Behavior of Fine Recycled Concrete Aggregate Concrete with the Mineral Admixtures
Materials, 2020
The paper describes the mechanical behavior of fine recycled concrete aggregate (FRCA) concrete according to the mineral admixtures. Three types of the mineral admixtures, i.e., fly ash (FA), ground-granulated blast-furnace slag (GGBS), and silica fume (SF), are used and the replacement ratios of FRCA are 50% and 100%. The dosages of the admixtures of FA, GGBS, and SF are determined with the normal dosage (30%, 40%, and 5.0%, respectively) based on the ACI committee reports (No. 232, 233, and 234) and half-normal dosage. The mechanical performance is investigated with the compressive and splitting tensile strength, and elastic modulus. Additionally, the total porosity is measured in natural fine aggregate (NFA) and FRCA 100% replaced specimens by mercury intrusion porosimetry (MIP) for investigating the relationship with the compressive strength. Based on the experimental test results, the mineral admixtures improve the mechanical performance of FRCA concrete. The effective dosages ...
KnE engineering, 2020
This study investigates the possible effects of incorporating different industry wastes during manufacturing of concrete, with percentages ranging from 0% to 30%, and assesses the influence of these combinations (mineral additions and recycled aggregates) on the properties of a recycled concrete comprised of these two main constituents products. Recycled concrete samples with different combinations of mineral additions at various dosages were used to determine these properties in the fresh and hardened states. The "Design-expert" methodology was used to analyse the results after 7, 14 and 28 days, identifying correlations and the effects of the different variables. The results obtained showed the advantageous effect of incorporating the pozzolana and slag into the concrete mixture at dosages of 15% and 30%, they also demonstrated the low optimal percentage of marble fillers of 5%. These findings suggest that replacing clinker with industrial waste could limit the dust and CO 2 emissions into the atmosphere during concrete manufacture, offering environmental advantages as well as conserving the natural resources of aggregate recovery from C&D wastes.
Investigating Composite Cement Concrete Utilizing Recycled Aggregate And Stone Dust
Educational Administration: Theory and Practice, 2023
Evolution of technology in our society is still highly pervasive in nature and the upcoming process of globalization significantly affects the state of the environment. Along with the increase in population, unbounded pumping of raw materials for production of materials and urbanization of the environment, there is wide range of increase in harmful emissions and waste generation. Mineral resources are limited significantly. Resources to feed our growing population are limited as well as the materials required to construct buildings and infrastructure. The use of auxiliary cementitious materials such as fly ash (FA) and ground granulated blast furnace slag (GGBS). Recent studies show a steady increase in use of fly ash and blast furnace slag in construction industry as an economical and effective solution for partial replacement of cement. An arduous issue when replacing cement is that the auxiliary materials affect concrete properties variously according to several factors such as the grade of cement, percentage of replacement, curing periods and environment condition. In order to determine how the concrete strength and its rheological properties can be affected by auxiliary material, this study investigates the strength properties of M25 grade of composite cement concrete in which coarse aggregate is replaced with 30% of recycled aggregate and fine aggregate is replaced with 20% & 30% of stone dust. The outcomes indicated that the addition of recycled aggregate and stone dust in composite cement concrete enhances not only the mechanical strength but also workability which eventually improves the properties of concrete.
Disposal of construction waste is now new challenge for the construction industry in this era. This is peak time to use Construction waste as recycled aggregate (RA) in concrete manufacturing for sustainable development. Recycled aggregate concrete (RAC ) is the future to save environment from the waste. Supplementary Cementing Materials (SCMs) are widely used these days to improve the durability of c oncrete. Silica fume has gained worldwide acceptance due to its high pozzolanic reactivity compared to oth er SCMs . Using mineral admixtures as cement replacement substance in concrete ha s a tendency to increase by the future in order to provide greater sustainability in construction industry. O n the other hand Quartz is the second most abundant mineral in the Earth's cont inental crust, after feldspar. It is used as SCM in concrete. In this study, replacements of cement with silica fume 4%, 8% and12% & mineral quartz 5% for concrete mix of M35 and M40 grade. The natural aggregate is replaced by recycled aggregate (RA) with 30%. This paper study conducted on water absorption and sorptivity test on recycled aggregate concrete (RAC). The experiment result analysis shows that durability of 8% SF and 5% Quartz are better than other replacements.
Effect of Recycled Aggregate and Fly Ash in Concrete
Waste arising from construction and demolition constitutes one of the largest waste streams within the developed and developing nations. The rapid growth in construction and depleting natural resources demands the recycling and reusing technology to be adopted in construction field. The use of recycled coarse aggregate (RCA) and fly ash (FA) is one of theapproaches towards this need.Use of RCA and FA in concrete can be useful for environmental protection and economical terms. In this experimental study the natural coarse aggregate (NCA) is replaced with RCA at different percentage and the mechanical strength of concrete is tested. In addition the FA is introduced as replacement of Cement.The objective of present study is to determine the sustainability of RCA as an alternate material to NCA and to compare the workability, density and compressive strength result using FA. The mix designing is done for water cement ratio 0.5. Cubes are casted by replacing virgin aggregate and cement with 10%, 20%, 30%, 40% RCA and FA and compressive strength is checked. Obtained results are then used to establish an empirical relationship between the strength of concrete by using percentage of RCA and percentage of FA. Results shows that RCA and FA up to 30% can be used for making concrete.
exprimental effect of using silica fume and fly ash on mechanical properties of recycled concretes
— This paper presents the results of a laboratory study on the mechanical performance of recycled concretes prepared with incorporation of two mineral admixtures including silica fume (SF) and fly ash (FA). The recycled aggregates concrete (RAC) was prepared by using 0, 25, 50 and 100% coarse aggregate replacement. The compressive strength, splitting tensile strength (SPT) and ultrasonic pulse velocity (UPV) of concrete mixes were completed. The results showed that the pozzolanic materials cannot have a significant effect on compressive strength loss trend. In contrast, the ultimate compressive strength of recycled concretes strongly effected by pozzolanic materials. The SPT and UPV test results showed that compare with FA, the use of SF reduced the negative effect of high replaced percentage of recycled aggregates. Index Terms— Fly Ash (FA), Silica Fume (SF), Mechanical Properties, Recycled Coarse Aggregate, Recycled Concrete.
MECHANICAL CHARACTERISTICS OF RECYCLED AGGREGATE AND MINERALS ADMIXED HIGH-PERFORMANCE CONCRETE
IRJET, 2023
In this research paper, we have studied the effect of recycled aggregates and minerals in physical characteristics on high-performance concrete (HPC) when mixed in it. The present study consists of and considered the effect of many properties of concrete components which are not taken into account by the traditional mix design method. The suggested mix design process follows the rule and regulations of the (BIS) Bureau of Indian Standards as well as the American Concrete Institute (ACI). The analysis of recycled aggregate (mostly demolished concrete) as a substitute for natural aggregates admixed with minerals, "silica fume" has been done based on an experiment conducted on HPC. M60 mix design is used in this study. At first, different materials used for making HPC are identified and later then with the help of mix design code, proportional quantities of materials are to be found. The proportions of