scholarly journals Utilization of Recycled Aggregate Concrete for Marine Site Based on 7-Year Field Monitoring

Author(s):  
Wichian Chalee ◽  
Tieng Cheewaket ◽  
Chai Jaturapitakkul

AbstractThis research aimed to create value of construction and demolition waste to be able used as a recycled coarse aggregate (RCA) in durable concrete, based on 7-year field investigation in marine site. Fly ash was used to substitute Portland cement type I in RCA concrete varied from 0 to 50% by weight of binder with three W/B ratios and comparing to natural aggregate (NA) concrete. Cubical concrete specimens were cast having round steel bars embedded with various concrete coverings to evaluate the durability performances. After 28-day curing, the specimens were placed at a tidal zone in the gulf of Thailand and investigated both mechanical and durability performances at 7-year exposed period. Based on site monitoring, 15–25% fly ash RCA concrete with W/B ratio of 0.40 would be advantaged to resist destruction due to the marine attack when compared with NA concrete with the same water-to-binder ratio.

Author(s):  
Sharifah Salwa Mohd Zuki ◽  
◽  
Shahiron Shahidan ◽  
Shivaraj Subramaniam ◽  
◽  
...  

This paper discussed the recycled aggregates produced from construction and demolition waste and their utilization in concrete construction. Along with a brief overview of the engineering properties of recycled aggregates, the paper also summarizes the effect and use of recycled aggregates on the properties of fresh and hardened concrete. The recycled aggregates were treated with epoxy resin to reduce the water absorptions with different percentages of resin such as 0%, 25%, 50%, 75%, and 100%. Epoxy resin is widely used in recent years owing to the enhancing of mechanical and durability of the concrete. This research also showed, recycled aggregate concrete are close proximity to normal concrete in terms of split tensile strength, compression strength and wet density. The low usage of resin was obtained good strength concrete compared to high percentage contained treated aggregates due to low bonding between material.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4620
Author(s):  
Fan You ◽  
Surong Luo ◽  
Jianlan Zheng ◽  
Kaibin Lin

Using recycled aggregate in concrete is effective in recycling construction and demolition waste. It is of critical significance to understand the fatigue properties of recycled aggregate concrete (RAC) to implement it safely in structures subjected to repeated or fatigue load. In this study, a series of fatigue tests was performed to investigate the compressive fatigue behavior of RAC. The performance of interfacial transition zones (ITZs) was analyzed by nanoindentation. Moreover, the influence of ITZs on the fatigue life of RAC was discussed. The results showed that the fatigue life of RAC obeyed the Weibull distribution, and the S-N-p equation could be obtained based on the fitting of Weibull parameters. In the high cycle fatigue zone (N≥104), the fatigue life of RAC was lower than that of natural aggregate concrete (NAC) under the same stress level. The fatigue deformation of RAC presented a three-stage deformation regularity, and the maximum deformation at the point of fatigue failure closely matched the monotonic stress-strain envelope. The multiple ITZs matched the weak areas of RAC, and the negative effect of ITZs on the fatigue life of RAC in the high cycle fatigue zone was found to be greater than that of NAC.


2018 ◽  
Vol 760 ◽  
pp. 193-198 ◽  
Author(s):  
Kristina Fořtová ◽  
Tereza Pavlů

This paper presents research results of recycled fine aggregate concrete testing. The main aim of this contribution is verification of properties of fine aggregate concrete with partial replacement of fine natural aggregate by recycled masonry aggregate originated from construction and demolition waste. The influence of partial replacement of natural sand to mechanical properties and freeze-thaw resistance is described. The compressive strength and flexural strength were tested at the age of 28 and 60 days and after 25, 50, 75 and 100 freeze-thaw cycles. Partial replacement of natural sand was 0, 25 and 50 % for all these tests. Prismatic specimens were examined.


2020 ◽  
Vol 70 (337) ◽  
pp. 210 ◽  
Author(s):  
R. L.S. Ferreira ◽  
M. A.S. Anjos ◽  
E. F. Ledesma ◽  
J. E.S. Pereira ◽  
A. K.C. Nóbrega

This study investigated the physical-mechanical effects of cement-lime mortars containing recycled aggregate of construction and demolition waste (CDW). The natural aggregate (NA) was replaced by volume at 25%, 50%, 75% and 100% by mixed recycled aggregate (MRA) obtained from the CDW crushing. Five types of mortars were prepared with a volumetric ratio of 1:1:6 (cement, lime and aggregate) and water/binder ratio based on the fixed consistency of 260 mm. The effects of MRA on fresh and hardened mortars’ properties were analyzed. The results were analyzed using a one-way ANOVA. MRA incorporation improved most of the physical-mechanical properties of mortars tested, except for hardened bulk density, water absorption and porosity. In the long-run, mechanical strengths significantly increased in all compositions, especially those with higher percentages of MRA. The results obtained showed that the use of MRA in masonry mortars is an alternative to reduce the generation of waste and consumption of natural resources.


Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
António G. B. Lima ◽  
Castorina S. Vieira

This work aims to study the influence of using construction and demolition waste in the replacement of coarse and fine aggregate to produce recycled aggregate concrete (RAC). A moderate compressive strength concrete made with usual fine and coarse aggregate was used as a benchmark material. Compressive and split tensile tests were performed using 120 cylindrical concrete specimens with 150 mm diameter and 300 mm length. Four-point flexural tests in reinforced beams made with conventional concrete and RAC were performed. The results obtained showed that the use of recycled fine aggregates, in both percentages of substitution investigated—50% and 100%— did not generate any deleterious influence on the values of compressive strength and split tensile strength of the RACs produced. Tin fact, the mechanical strengths of RACs produced with recycled fine aggregate were equal or higher than those from the reference concrete. The same behavior was not observed, however, when the recycled coarse aggregate was used. For this case, decreases in concrete mechanical strengths were observed, especially in compressive strength, with values around 35% lower when compared to the reference concrete. Tensile mechanical tests results confirmed the excellent behavior of all RACs made with replacement of usual fine aggregates by recycled. Bending tests performed in reinforced RAC beams had as objective to evaluate the deformation profile of the beams. The obtained results showed that RAC beams with full replacement of usual fine aggregate by the recycled aggregates have presented little changes in the global behavior, an aspect that encourages its use.


2019 ◽  
Vol 10 (1) ◽  
pp. 216 ◽  
Author(s):  
Pablo Tamayo ◽  
Joao Pacheco ◽  
Carlos Thomas ◽  
Jorge de Brito ◽  
Jokin Rico

The search for more sustainable construction materials, capable of complying with quality standards and current innovation policies, aimed at saving natural resources and reducing global pollution, is one of the greatest present societal challenges. In this study, an innovative recycled aggregate concrete (RAC) is designed and produced based on the use of a coarse recycled aggregate (CRA) crushing concrete with electric arc furnace slags as aggregate. These slags are a by-product of the steelmaking industry and their use, which avoids the use of natural aggregates, is a new trend in concrete and pavement technology. This paper has investigated the effects of incorporating this type of CRA in concrete at several replacement levels (0%, 20%, 50% and 100% by volume), by means of the physical, mechanical and durability characterization of the mixes. The analysis of the results has allowed the benefits and disadvantages of these new CRAs to be established, by comparing them with those of a natural aggregate concrete (NAC) mix (with 0% CRA incorporation) and with the data available in the literature for concrete made with more common CRA based on construction and demolition waste (CDW). Compared to NAC, similar compressive strength and tensile strength values for all replacement ratios have been obtained. The modulus of elasticity, the resistance to chloride penetration and the resistance to carbonation are less affected by these CRA than when CRA from CDW waste is used. Slight increases in bulk density over 7% were observed for total replacement. Overall, functionally good mechanical and durability properties have been obtained.


2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Carolina Shimomura Nanya ◽  
Fernanda Giannotti da Silva Ferreira ◽  
Valdirene Maria da Silva Capuzzo

ABSTRACT This paper investigates how the use of construction and demolition waste can affect the durability and affect the mechanical performance of concrete. tests such as compressive strength, tensile strength by diametral compression and modulus of elasticity were performed. Regarding durability, tests such as water immersion, void content and specific mass, water absorption by capillarity, electrical resistivity, the penetration depth of chloride ions, accelerated carbonation and a test evaluating the synergic effect of carbon dioxide and chloride ion penetration were performed. The coarse natural aggregate was replaced with coarse recycled aggregate in concrete mixes at the following ratios: 30%, 50%, 70%, and 100%. The results indicate that the parameters of the concrete produced with recycled aggregate, especially up to 50% replacement level, meet the concrete quality requirements, regarding the mechanical properties and durability.


2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mirjana Malešev ◽  
Vlastimir Radonjanin ◽  
Gordana Broćeta

Following an example of the world's great powers that developed the recycling industry after natural disasters and wars, the paper points to the possibility of using large quantities of construction and demolition waste, generated as a result of the recent floods in the BiH and Serbia. Based on the years of extensive experimental research, and the research conducted by eminent experts, an overview is provided of the most basic properties and application of recycled aggregate concrete. It has been shown that the application of coarse recycled concrete aggregate, as the component materials in the concrete mixtures, it is possible to produce structural concrete that can be satisfactory and even with high quality, which primarily depends on the characteristics of crushed demolished concrete.


2016 ◽  
Vol 847 ◽  
pp. 156-165
Author(s):  
Marco Pepe ◽  
Eduardus Koenders ◽  
Romildo Dias Toledo Filho ◽  
Enzo Martinelli

The construction sector is more and more committed to reduce its environmental impacts. One of the key actions undertaken in the last decade deals with the ability of turning construction and demolition waste into new raw materials. For instance, the use of recycled aggregates for producing new concrete was one of the most investigated. Thus, in the last decade, plenty of researches were involved in project on characterising the mechanical behaviour of concrete made with recycled aggregates. However, these projects were mainly experimental in nature and generally led to merely empirical formulations. Conversely, this paper is intended at providing a contribution for predicting the mechanical properties of Recycled Aggregates Concrete (RAC). Particularly, it aims at quantifying the effect of replacing ordinary aggregates with Recycled Concrete Aggregates (RCA) on the resulting compressive strength of RAC. To this end, a conceptual model considering both the relevant physical properties of regular and recycled aggregates, including the attached mortar content, and the hydration reactions of Portland cement paste is proposed. The actual predictive capacity of the proposed model is assessed through an experimental validation against experimental tests carried out on several concrete batches produced with various values for the different keys parameters, such as the nominal water-to-cement ratio, the aggregates replacement ratio and the initial moisture condition of aggregates. Both the experimental data and the theoretical formulations proposed in this paper stem out from the inter-university collaboration developed as part of the EU funded EnCoRe Project (www.encore-fp7.unisa.it).


Sign in / Sign up

Export Citation Format

Share Document