scholarly journals Microstructure Analysis and Strength Characterization of Recycled Base and Subbase Materials Using Scanning Electron Microscope

2020 ◽  
Author(s):  
Tanvir Imtiaz ◽  
Asif Ahmed ◽  
MD Sahadat Hossain ◽  
Mohammad Faysal
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Unconfined Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Microstructural Properties ◽  
Reclaimed Asphalt ◽  
Scanning Electron

The reuse of recycled crushed concrete aggregate (RCCA) and reclaimed asphalt pavement (RAP) can provide a sustainable solution for the disposal of C&D materials instead of sending it to landfill. More importantly, it will save energy and reduce impact on the environment. Several states in USA are using RCCA and RAP as base materials for years, focusing on the quality of the recycled materials. The structure of Recycled Aggregate (RA) is more complex than Natural Aggregate (NA). RAs have old mortar adhered on them that forms a porous surface at interfacial transition Zone (ITZ) and prevents new cement mix from bonding strongly with the aggregates. The objective of this work was to correlate microstructural properties like micro-porosity, inter and intra aggregate pores with the unconfined compressive strength (UCS) of RAP and RCCA molds, mixed at different proportions. In this paper, the quantity of micro-pores and their effect on the strength of mixed materials is used as the basis of microstructural analysis of recycled concrete and reclaimed asphalt. Microstructural properties obtained from the analysis of scanning electron microscope (SEM) images were correlated with unconfined compressive strength. Intra-aggregate and inter-aggregate pores were studied for different ratios of cement treated mixture of RAP and RCCA. The results show that the number of pores in the mixture increases considerably by adding RAP, which eventually causes reduction in unconfined compressive strength. In addition, significant morphological and textural changes of recycled aggregates were observed by SEM image analysis.

scholarly journals Microstructure Analysis and Strength Characterization of Recycled Base and Sub-Base Materials Using Scanning Electron Microscope

2020 ◽  
Vol 5 (9) ◽  
pp. 70
Author(s):  
Tanvir Imtiaz ◽  
Asif Ahmed ◽  
MD Sahadat Hossain ◽  
Mohammad Faysal
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Unconfined Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Microstructural Properties ◽  
Reclaimed Asphalt ◽  
Base Materials ◽  
Scanning Electron

The reuse of recycled crushed concrete aggregate (RCCA) and reclaimed asphalt pavement (RAP) can provide a sustainable solution for the disposal of C&D waste materials instead of sending them to landfills. More importantly, it will conserve energy and reduce environmental concerns. Several states in the USA have been using RCCA and RAP as base materials for years, focusing on the quality of the recycled materials. The structure of Recycled Aggregate (RA) is more complex than that of Natural Aggregate (NA). RAs have old mortar adhered on them that forms a porous surface at the interfacial transition Zone (ITZ) and prevents new cement mix from bonding strongly with the aggregates. The objective of this study was to correlate microstructural properties such as microporosity, inter and intra aggregate pores with the unconfined compressive strength (UCS) of RAP and RCCA molds, mixed at different proportions. In this paper, the quantity of micropores and their effect on the strength of mixed materials is used as the basis of microstructural analysis of recycled concrete and reclaimed asphalt. Microstructural properties obtained from analyzing scanning electron microscope (SEM) images were correlated with unconfined compressive strength. Intra-aggregate and interaggregate pores were studied for different ratios of cement treated mixture of RAP and RCCA. The results show that addition of RAP considerably increases the number of pores in the mixture, which eventually causes reduction in unconfined compressive strength. In addition, significant morphological and textural changes of recycled aggregates were observed by SEM image analysis.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete with Different Replacement Ratios

2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
Author(s):  
Hai Yong Cai ◽  
Min Zhang ◽  
Ling Bo Dang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Failure Mode ◽  
Failure Process ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Replacement Ratio ◽  
Aggregate Concrete

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.

Study on Compressive Performances of Fiber Reinforced Mortar with the Application of Jute and PP

2014 ◽  
Vol 936 ◽  
pp. 1356-1360
Author(s):  
Jun Fei Yin ◽  
Yu Zhang ◽  
Ting Ting Yan ◽  
He Qiu
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polypropylene Fiber ◽  
Jute Fiber ◽  
Fiber Reinforced ◽  
Compressive Properties ◽  
Jute Fibers ◽  
Scanning Electron

In this study, jute fibers and polypropylene fiber (PP) were added into cement-based mortar to improve their compressive strength. Results obtained have shown that the compressive strength of the motar was perfect with jute fiber of 19mm length at the fiber contents of 0.8 kg·m-3. The reinforcing mechanism of fiber in the motar was analyzed by means of comparing of the mortar compressive properties under different circumstances, and the testing results of scanning electron microscope (SEM) and the addition of filament in experiments.

scholarly journals Reusing of Construction Debris in Plain Concrete Elements

2021 ◽  
Vol 9 (3) ◽  
pp. 81-87
Author(s):  
A. Abdelrahman Abuserriya ◽  
B. Bashir H. Osman ◽  
C. Salma Y. Mahmoud
Keyword(s):  
Compressive Strength ◽  
Sea Water ◽  
Plain Concrete ◽  
Absorption Capacity ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Content ◽  
Concrete Production ◽  
Concrete Blocks

Construction is a serious environmental problem and a challenge for people who concerned with sustainability in the construction field. Previous studies showed positive results for the use of recycled aggregates in the concrete production. This study portrays the results for utilizing construction debris for casting different types of concrete blocks. The recycled concrete debris was used in different ratios (0%, 50%, and 100%) in replacement for natural coarse aggregates for different targeted compressive strength (B250, B300, B350 and B400). Two types of water (pure and sea water) were used for curing the blocks. In addition, hollow block and paving block were casted with different ratios of recycled aggregate (0%, 20%, 45% and 100%) and cured with two types of water. The results showed a decrease in compressive strength with the increase recycled aggregate content. It was also noticed that the absorption capacity increases with high recycled aggregate content.  

scholarly journals The Filler Effect on Compressive Strength of Sulfur Concrete

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wenwei Lin ◽  
Fan Fei ◽  
Qunjie Li
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Fly Ash ◽  
Scanning Electron Microscope ◽  
Chemical Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compressive Performance ◽  
Bonding Mode ◽  
Scanning Electron

The sulfur concrete samples were prepared by the optimized process, which were mixed with cement, fly ash and slag, respectively. The influence of the type and content of filler on the compressive strength of sulfur concrete was studied. The phase and micromorphology of filler and sulfur mixture were characterized by X-ray diffraction and scanning electron microscope, and the bonding mode was studied. The results show: the cement filler has the best effect on the compressive performance of sulfur concrete,and the compressive strength is 87.2 MPa by adding cement filler with the same quality as sulfur; there is no chemical reaction between filler and sulfur, and the filler is physically bonded to sulfur matrix.

scholarly journals Recycled aggregate amount variation of fraction 4/8 mm and 8/16 mm in the concrete mixture

2020 ◽  
Vol 15 (2) ◽  
pp. 49-54
Author(s):  
Jozef Junák ◽  
Natália Junáková
Keyword(s):  
Compressive Strength ◽  
Reference Sample ◽  
Point Of View ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Economic Point ◽  
Aggregate Fractions ◽  
Aggregate Amount

AbstractThe introductory part of the paper is devoted to the classification of aggregates according to various criteria, one of them is the geographical origin of aggregates. From the point of view of the circular economy, the use of recycled aggregates comes to the fore, mainly from the ecological point of view but also from the economic point of view.The paper summarizes the results of research focused on the variation of the amount of 2 Recycled concrete aggregate fractions in concrete, followed by an evaluation of the effect of the presence of recycled material in the mixture on the selected property, specifically compressive strength. The highest compressive strength 34.7 MPa after 28 days hardening reached sample containing 100% recycled fraction 4/8 mm, and 60% recycled fraction 8/16 mm. This value is only slightly different from the compressive strength of the reference sample (34.4 MPa).

scholarly journals Impact of Nanosilica in Ordinary Portland Cement Over Its Durability and Properties

2021 ◽  
Author(s):  
Gude Reddy Babu ◽  
Pala Gireesh Kumar ◽  
Nelluru Venkata Ramana ◽  
Bhumireddy Madhusudana Reddy
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Flexural Strength ◽  
Scanning Electron Microscope ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
X Ray Diffraction ◽  
Cement Strength ◽  
The Impact ◽  
Scanning Electron

The present examination illustrates the impact on the hardened and fresh cement mortar and cement with the inclusion of nanosilica of size 40 nm in various environmental conditions (UltraTech, India). It is quite notified that an elevation in compressive strength as well as flexural strength along with an improvisation in the performance and life span of cement mortar. The samples of M5 grade blended with a ninety percentage of concrete and remaining with nanosilica was identified to have a finer working elevation in as well as in standards when collated with the conventional cement mortar. The corollary of hardened and fresh cement, strength parameters were looked upon with the aid of XRD (X-ray Diffraction). Also, the SEM (Scanning Electron Microscope) test holds a predominant role in analysis.

scholarly journals Performance of Recycled Aggregate Concrete for M25 Grade Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 4694-4700
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Inorganic Particles ◽  
Natural Aggregates

Recycled aggregates (RCA) are the aggregates which are made up of crushed, inorganic particles that are obtained from the construction demolition debris. Now a day’s protection of environment is the ultimate challenge to the society. So the usage of RCA’s is the best alternative for the aggregates which are obtained naturally in the construction activity. The scope of using these recycled concrete aggregates is increasing day by day. It reduces the cost effectively as we are using waste concrete as recycled aggregates. The main focus of this paper is to use find the strength qualities of recycled aggregates so as to use it as an alternative for the natural aggregates in high strength concrete for various construction activities. Comparison of workability, compressive strength, tensile strength, elastic modulus and flexural strength of recycled aggregate concrete is made with natural aggregate concrete. Here M25 grade concrete is taken and the natural aggregates were replaced with recycled aggregates in various percentages of 0%, 25%, 50%, 75% and 100%. The mix design for these replacement ratios are done by using code of IS 10262-2009. In order to determine the properties which were mentioned above a total of 60 cubes, 10 beams and 40 cylinders were casted. The compressive strength and tensile strength of RCA concrete have been determined for 7 days and 28 days where as the modulus of elasticity and the flexural strength of RCA concrete are determined after curing for the period of 28 days. The tests done on RCA concrete are compared with concrete which is obtained by natural aggregates As per IS codification the parameters which were determined are reducing moderately as the amount of aggregates which are recycled is being raised

scholarly journals Experimental Characterization of Recycled Aggregate Concrete

2019 ◽  
Vol 303 ◽  
pp. 05004
Author(s):  
Khaoula NAOUAOUI ◽  
Azzeddine BOUYAHYAOUI ◽  
Toufik CHERRADI
Keyword(s):  
Compressive Strength ◽  
Developed Countries ◽  
Tourism Industry ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Different Types ◽  
Natural Aggregates

The field of construction is evolving rapidly over the last decade. This is justified by the evolution of human activity in various fields mainly tourism, industry … and the aging of several buildings which implies a renovation or a demolition/re-construction. These construction activities involve a large need for aggregates for new construction and a large tonnage of waste from demolitions. In order to remedy this, various stakeholders in the field (suppliers, cement works, research centers, etc.) have valued recycled aggregate concrete (RAC). Recycled aggregates concrete is considered a new type of concrete based on the use of aggregates retrieved from the demolished structures instead of natural aggregates. This replacement affects, for sure, the characteristics of the concrete produced specially the mechanical properties. Developed countries have made a great progress in normalizing the use of recycled aggregates (RA) in concrete implementation as a result of many studies done since 80’s. In Morocco, recycled aggregates do not have any specific standards, and is used mainly in roads and pavements construction. Even if it’s not normalized this use is not recent, in 1999 during the rehabilitation of the expressway road of Casablanca which was severely damaged on both channels, the authorities have opted for the reuse of aggregates instead of reloading the existing pavement with a new one. The study is based on the use of recycled concrete crushed from an old building in Rabat- Morocco as aggregates and compared it with naturel aggregates from Morocco to determinate the effect of this replacement on several characteristics of concrete. This article is aiming to investigate experimentally the effect of RA in concrete using different replacement levels, different types of adjuvant and different percentages of it. The results show that over 30% of replacement, the compressive strength decreases considerably for basic concrete. In order to increase the compressive strength for the RAC with a percentage of replacement over 50%, we used different types of additives (Plasticizer, superplasticizer and new generation superplasticizer) and different percentage of it (0.5%, 1% and 1.5%): We concludes that, for our case, the add of plasticizer gives the best result and that the 1% replacement is the optimum percentage. The tests done on RCA made by plasticizer with different replacement level confirm the results without plasticizer: Compressive strength decreases when the replacement percentage increases.

Study on PbSn Composites Produced by Powder Metallurgy as Core Bullet Projectile

2013 ◽  
Vol 789 ◽  
pp. 60-65 ◽  
Author(s):  
Widyastuti ◽  
Vuri Ayu Setyowati ◽  
Taufik Akbar
Keyword(s):  
Compressive Strength ◽  
Energy Transfer ◽  
Electron Microscope ◽  
Powder Metallurgy ◽  
Scanning Electron Microscope ◽  
Performance Test ◽  
Mechanical Performance ◽  
Compression Tests ◽  
Compacting Pressure ◽  
Scanning Electron

PbSn composites have been prepared by powder metallurgy for Advance Energy Transfer Bullet Application. Sn compositions was variety 5, 10, 15wt%. The compacting pressure performed at 10, 15, and 20 MPa. Temperature and holding time of sintering constantly in 150OC for 2 hours. The microstructure and mechanical performance of PbSn composites are investigated by Scanning Electron microscope (SEM), and compression tests. The results show that the Pb-15%wtSn Composite which is compacted in 20 MPa has result greatest density which was 10.969 gr/cm3and the smallest porosity (1.5%). Mechanical performance test of PbSn composite show the greatest hardness, compressive strength and modulus elasticity reach are 11.01 HV, 46.82 MPa and 34.96 GPa

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