Durability and Mechanical Properties of Self-Compacting Concrete Incorporating Recovered Filler from Hot Mix Asphalt Plants and Recycled Fine Aggregate

2021 ◽  
Vol 894 ◽  
pp. 95-101
Author(s):  
Sepehr Ghafari ◽  
Fereidoon Moghadas Nejad ◽  
Ofelia Corbu

In this research, a sustainable approach is followed to develop efficient mixtures incorporating recycled fine aggregate (RFA) remained from structure demolition as well as limestone filler (LF) from production of hot mix asphalt (HMA). The LF is a byproduct of the drying process in HMA production plant which is not entirely consumed in the production of the HMA and must be hauled and disposed in landfills. The maximum particle size of the LF is approximately 40 µm. Self-Compacting Concrete (SCC) mixtures were designed replacing 5% and 10% of the cement with LF. Incorporation of 50%, and 100% RFA with the fines in the mixtures were considered with and without addition of the LF. Due to the formwork and prefabrication restrictions, the paste volume and the high range water reducer content were tuned in such a way that the slump flow of the mixtures remained between 660 mm to 700 mm without segregation. Durability and mechanical performance of the mixtures were evaluated by resistance against freeze-thaw scaling exposed to deicing agents and compressive strength. It was observed that the SCC mixtures containing 10% LF outperformed those without the use of LF while 5% SCC mixtures did not exhibit tangible superiority. Incorporation of RFA as the fine fraction degraded the durability of all the mixtures. While replacing all the fine fraction with RFA significantly impaired durability and compressive strength, 50% RF mixtures could be designed containing 10% LF that remained in the allowable limits.

2012 ◽  
Vol 253-255 ◽  
pp. 432-435
Author(s):  
Jiu Su Li ◽  
Chun Li Qin

Fine aggregate can be extracted from waste concrete by series of processing. The recycled fine aggregate can then be utilized to manufacture recycled fine aggregate mortar (RFAM) or recycled fine aggregate concrete (RFAC). Air entraining agent was added in RFAM to improve its mechanical performance. The influence of the dosage of the air entraining agent on both the compressive and flexural strength of the RFAM was explored after 7 days and 28 days curing. The optimum dosage of the air entraining agent was determined.


Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1821 ◽  
Author(s):  
Robert Bušić ◽  
Mirta Benšić ◽  
Ivana Miličević ◽  
Kristina Strukar

The paper aims to investigate the influence of waste tire rubber and silica fume on the fresh and hardened properties of self-compacting concrete (SCC) and to design multivariate regression models for the prediction of the mechanical properties of self-compacting rubberized concrete (SCRC). For this purpose, 21 concrete mixtures were designed. Crumb rubber derived from end-of-life tires (grain size 0.5–3.5 mm) was replaced fine aggregate by 0%, 5%, 10%, 15%, 20%, 25%, and 30% of total aggregate volume. Silica fume was replaced cement by 0%, 5%, and 10% of the total cement mass. The optimal replacement level of both materials was investigated in relation to the values of the fresh properties and mechanical properties of self-compacting concrete. Tests on fresh and hardened self-compacting concrete were performed according to the relevant European standards. Furthermore, models for predicting the values of the compressive strength, modulus of elasticity, and flexural strength of SCRC were designed and verified with the experimental results of 12 other studies. According to the obtained results, mixtures with up to 15% of recycled rubber and 5% of silica fume, with 28 days compressive strength above 30 MPa, were found to be optimal mixtures for the potential future investigation of reinforced self-compacting rubberized concrete structural elements.


Author(s):  
L. Allen Cooley ◽  
Jingna Zhang ◽  
Michael H. Huner ◽  
E. Ray Brown

Thin-lift hot-mix asphalt (HMA) layers are utilized in almost every maintenance and rehabilitation application. These mix types require smaller maximum particle sizes than do most conventional HMA surface layers. Although the primary functions of thin-lift HMA are to level the pavement surface, smooth the surface, or slow the deterioration of the existing pavement, or all three, these mixes may also provide some structural improvement, depending on the layer thickness placed. The use of manufactured aggregate screenings (fine aggregate stockpiles) as the sole aggregate portion of an HMA mixture was evaluated in this study. Mixes of this nature have the potential for use as thin-lift HMA layers. Two different sources of aggregate screenings, granite and limestone, were utilized to design mixtures at varying design air void contents and then tested for rut susceptibility. The use of a neat versus a modified asphalt binder was also evaluated, as well as the potential advantages of cellulose fiber additives. These mixtures using 100% manufactured screenings proved to be acceptable with regard to rutting resistance. No work was performed in this study to examine thermal cracking or durability.


2012 ◽  
Vol 482-484 ◽  
pp. 1101-1104
Author(s):  
Huan Qiang Liu ◽  
Xi Chen

The workability of self-compacting concrete is influenced greatly by aggregate. In this study, the effects of aggregate gradation, maximum particle size, sand percentage and particle shape on the workability of self-consolidating concrete were investigated. The results showed that the compressive strength and workability of self-compacting concrete were increased by increasing the particle size of aggregate, optimizing gradation, choosing proper sand percentage and increasing shape index in a certain range.


Author(s):  
Yuji Nakata ◽  
Koji Takasu ◽  
Hidehiro Koyamada ◽  
Hiroki Suyama

In Japan, it is forecasted that massive amounts of concrete waste material will be generated in the future as a result of demolition of many buildings, and expansion of the use of recycled aggregate is expected. In this study, it was verified the effect when relatively large amount of admixture is mixed, a combination of recycled fine aggregate of different quality and various admixtures, combination of each admixture in order to realize high strength and high durability by using recycled aggregate. The increase in the drying shrinkage ratio due to the deterioration of the recycled fine aggregate quality was larger than the fluctuation due to the admixture mixing ratio and the drying shrinkage ratio was distributed by forming a group for each quality of recycled fine aggregate. In the relationship between the pore volume and the compressive strength, when evaluated with pore volume of 2 μm or less in both cases, a good linear relationship could be confirmed. The relationship between the pore volume and the drying shrinkage rate was similar. Therefore, it was suggested that compressive strength and drying shrinkage ratio of mortar contained composite recycled fine aggregate and admixture could be predicted by evaluating with the pore volume of 2 μm or less.


2012 ◽  
Vol 446-449 ◽  
pp. 2028-2032 ◽  
Author(s):  
Jian Geng ◽  
Yong Yong Chen ◽  
Jia Ying Sun ◽  
Wei Chen

In this article, the basic mechanical characters of recycled fine aggregate concrete (RFAC) are studied, and the relationships of recycled fine aggregate (RFA) content, minimum particle size and water content with them are also discussed according to results of cubic compressive strength (f¬¬cu), flexural strength (ff), splitting tensile strength(fts), axial compressive strength(fc)and Yang’s modulus (Ec). The results indicate that the use of RFA will induce mechanical properties of RFAC to deteriorate, and the deteriorated trend of it become more obviously with RFA content increased and minimum particle size reduced, in addition to, the early compressive strength of RFA develop slowly. The RFAC elastic modulus is significantly lower than ordinary concrete, besides, RFA on elastic modulus was significantly affected than other mechanical properties.


2020 ◽  
Vol 853 ◽  
pp. 109-114
Author(s):  
Xin Gu ◽  
Shu Chang Sun ◽  
Mao Xing Xu ◽  
Yi Liang Peng

From the compression test of steel fiber recycled mortar porous brick masonry, it was researched the effects of different amounts of steel fiber and recycled fine aggregate on compressive strength, failure morphology, elastic modulus, stress-strain law and Poisson's ratio performance. The test value is compared with the calculation formula of ordinary mortar porous brick given in GB 50003-2011.The test showed that the steel fiber recycled mortar porous brick masonry had better compressive strength and deformability.


2013 ◽  
Vol 368-370 ◽  
pp. 1090-1094
Author(s):  
Yuan Xu ◽  
Xiao Ping Wang ◽  
Juan Cheng ◽  
Dong Wang

Study four factors - water consumption , water-cement ratio , recycled fine aggregate replacement ratio of recycled coarse aggregate replacement rate - affect the regularity of the load-bearing hollow block compressive strength of recycled concrete by orthogonal test method , the test showed that , water consumption factors affect the compressive strength of recycled concrete block design with than the emphasis on the control of water consumption . Under the test conditions , the optimum mixture ratio of recycled concrete load-bearing block : water consumption of 160 kg / m 3 , the water cement ratio 0.45 , recycled fine aggregate replacement ratio of 30% recycled coarse aggregate replacement ratio of 30% .


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