scholarly journals Concrete Mix Design for Completely Recycled Fine Aggregate by Modified Packing Density Method

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3535
Author(s):  
Yibo Yang ◽  
Baixi Chen ◽  
Yan Su ◽  
Qianpu Chen ◽  
Zhiji Li ◽  
...  

The undesirable properties of conventional recycled fine aggregate (RFA) often limit its application in the construction industry. To overcome this challenge, a method for preparing completely recycled fine aggregate (CRFA), which crushes all concrete waste only into fine aggregate, was proposed. The obtained CRFA had high apparent density, and its water absorption was lower than that of the conventional RFA. To take advantage of the CRFA, this paper introduced the modified packing density method for the CRFA concrete mix design. The modified packing density method took account of the powder with a particle size of smaller than 75 μm in the CRFA and balanced both the void ratio and the specific surface area of the aggregate system. Concrete (grade C55) was prepared using the CRFA to validate the feasibility of the proposed method. The unit price of the prepared CRFA concrete was around 12.7% lower than that of the natural aggregate concrete. Additionally, the proposed procedure for the concrete mixture design could recycle all concrete waste into the new concrete and replace all the natural fine aggregate in the concrete mixture.

Author(s):  
Shreya Sunil Tolmatti ◽  
◽  
Sanskruti Jaywant Jadhav ◽  
Sakshi Satish Jadhav ◽  
Mayur M. Maske ◽  
...  

Particle packing technology is used to reduce the amount of cement in concrete by optimizing the concrete mix, resulting in more sustainable concrete. In this study, four different methods were used to determine the distribution of the mixture presented; packing density method, packing density method, IS code method, and packing density method. In the packing density method, the paste content that exceeds the voids will increase along with the increase in the quality of the concrete. In cases of packing density, the cement-water ratio decreases with the quality of the concrete. In the packing of too many trials, trials and tribulations should be carried out to achieve the ratio of water-cement and paste content for a certain grade of concrete. This correlation curve helps reduce the experiments involved in determining the ratio of semen and paste content for a given concrete quality. The water and cement contents for the packing density and the IS code method are almost the same for each particular concrete class. The workability of concrete achieved was more in the packing density method than the IS code method for the same concrete quality, because the water-cement ratio was slightly higher in the packing density method than the IS code method. The required fine aggregate particles are more in terms of packing density method compared to the IS code method. Therefore, more water and cement are required in terms of packing density. The correlation curve can be used to determine the ratio of water-cement and paste the content that exceeds the voids for a certain concrete quality


2014 ◽  
Vol 11 (2) ◽  
pp. 34-46 ◽  
Author(s):  
Narasimha Raj ◽  
◽  
Suresh G Patil ◽  
B. Bhattacharjee

2013 ◽  
Vol 701 ◽  
pp. 12-16 ◽  
Author(s):  
Mohd Irwan Juki ◽  
Khairunnisa Muhamad ◽  
Mahamad Mohd Khairil Annas ◽  
Koh Heng Boon ◽  
Norzila Othman ◽  
...  

This paper describes the experimental investigation to develop the concrete mix design Nomograph for concrete containing PET as fine aggregate. The physical and mechanical properties were determined by using mix proportion containing 25%, 50% and 75% of PET with water cement ratio (w/c) 0.45, 0.55 and 0.65. The data obtained showed that the inclusion of PET aggregate reduce the strength performances of concrete. All the data obtained were combined into one single graph to develop a preliminary mix design nomograph for PET concrete. The nomograph consist of ; relationship between compressive strength and water cement ratio; relationship between splitting tensile strength water cement ratio; relationship between splitting tensile strength and PET percentage and relationship between compressive strength and PET percentage. The mix design nomograph can be used to assists in selecting the proper mix proportion parameters based on the criteria required.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Ching-Yun Kao ◽  
Chin-Hung Shen ◽  
Jing-Chi Jan ◽  
Shih-Lin Hung

Pozzolanic concrete has superior properties, such as high strength and workability. The precise proportioning and modeling of the concrete mixture are important when considering its applications. There have been many efforts to develop computer-aided approaches for pozzolanic concrete mix design, such as artificial neural network- (ANN-) based approaches, but these approaches have proven to be somewhat difficult in practical engineering applications. This study develops a two-step computer-aided approach for pozzolanic concrete mix design. The first step is establishing a dataset of pozzolanic concrete mixture proportioning which conforms to American Concrete Institute code, consisting of experimental data collected from the literature as well as numerical data generated by computer program. In this step, ANNs are employed to establish the prediction models of compressive strength and the slump of the concrete. Sensitivity analysis of the ANN is used to evaluate the effect of inputs on the output of the ANN. The two ANN models are tested using data of experimental specimens made in laboratory for twelve different mixtures. The second step is classifying the dataset of pozzolanic concrete mixture proportioning. A classification method is utilized to categorize the dataset into 360 classes based on compressive strength, pozzolanic admixture replacement rate, and material cost. Thus, one can easily obtain mix solutions based on these factors. The results show that the proposed computer-aided approach is convenient for pozzolanic concrete mix design and practical for engineering applications.


2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Shoib Bashir Wani ◽  
Tahir Hussain Muntazari ◽  
Nusrat Rafique

The various approaches, established for concrete mix design, are not universal because design mixes are explicit to local climate, available materials, and type of exposure. The new-generation mix design method should be developed based on the performance criteria. The concrete strength obtained from the designed concrete mix and optimum cement content should not be considered as the only parameter for the suitability of the concrete mix. This study was carried to compare the proportioning of concrete mixes obtained by following procedures of Indian Standard (IS), American Concrete Institute (ACI) and British Standard (BS) of concrete mix design without the use of admixtures to validate for use in a moderate climate like Kashmir, India. The concrete mixes have been prepared with the necessary 28 days resistance in compression as “15 MPa, 20 MPa, 25 MPa, 30 MPa and 35 MPa”. The assessment of water-cement (w/c) ratio; cement, water, fine aggregate (FA) and coarse aggregate (CA) proportion was carried. The w/c ratio among all formulated mixes is significantly high in the BS method and low for IS method. The BS method uses less quantity and IS method uses the maximum quantity of cement. In addition, the ratio of total aggregate content (TAC) and the aggregate-cement ratio is higher in BS design method as compared to IS and ACI design methods. The aggregate content in ACI mix design appears to be consistent and it added to the relative high compressive strength. The specimens cast following BS guidelines failed to attain the target mean strength (TMS) due to a higher volume of aggregate content, high w/c proportion, less quantity of cement in the mix. The specimens cast by ACI and IS mix design upon compression testing showed higher results than the calculated TMS. The cost analysis per cubic meter of concrete revealed that IS and ACI mix proportioning are expensive than BS method. The IS procedure results in dense concrete followed by ACI procedure. It is expected that with a comprehensive investigation on selected design parameters concentrating more on local challenges, the present study will floor the way for the development and adoption of performance-based design mix selection for moderate climate.


2021 ◽  
Vol 2 (2) ◽  
pp. 239-254
Author(s):  
Johan Oberlyn Simanjuntak ◽  
Ros Anita Sidabutar ◽  
Humisar Pasaribu ◽  
Yetty Riris R Saragi ◽  
Sriyanti Sitorus

Concrete is a construction material consisting of a mixture of cement, aggregate, water and with or without admixture if needed. Coarse aggregate and fine aggregate serve as the main filler of concrete as well as reinforcement, while the cement and water mixtured serves as a binder between materials. To find out and study the behavior of each of these concrete constituents, it is necessary to know the characteristics of the materials made as constituents of the concrete. This study was conducted with the aim of comparing the most optimum type of coarse aggregate used and the comparison of the use of cement for coarse aggregate of crushed stone and coarse aggregate of gully originating from North Sumatera area, namely from the Wampu River in Binjai City as a concrete mixture to see its effect on compressive strength of concrete at the same concrete characteristics namely f’c 25 MPa. The results of the normal concrete mix design are obtained by using coarse aggregate of crushed stone and coarse aggregate of boulder in different amounts of cement. The coarse aggregate of crushed stone requires more cement with the amount of cement 411.1 kg/m3 than the coarse aggregate of gum with the amount of cement 388.9 kg/cm3.


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