The Properties of Fine Recycled Aggregate Concrete Containing Recycled Bricks from Construction and Demolition Waste

2018 ◽  
Vol 760 ◽  
pp. 193-198 ◽  
Author(s):  
Kristina Fořtová ◽  
Tereza Pavlů
Keyword(s):  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Natural Sand ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Recycled Fine Aggregate

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.

The Comparison of Properties of Fine Recycled Aggregate Concrete from Different Sources of Recycled Aggregate

2018 ◽  
Vol 760 ◽  
pp. 176-183 ◽  
Author(s):  
Tereza Pavlů
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Concrete Properties ◽  
Different Sources

The main aim of this contribution is comparison the properties of fine aggregate concrete with partial replacement of sand by fine recycled aggregate. The fine recycled aggregate originated from two different sources. The main topic of this article is the study of influence of the origin of FRA to fine aggregate concrete properties. The compressive strength, flexural strength and freeze-thaw resistance were tested. The mechanical properties and weight were examined after 28 and 60 days and after 25, 50, 75 and 100 cycles of freeze-thaw. Partial replacement of sand was 25 and 50 % for all these tests. The properties were investigated by using prismatic specimens.

Stress-Strain Behavior of Mortar Mixtures Containing Construction and Demolition Waste as Fine Aggregate

2014 ◽  
Vol 634 ◽  
pp. 300-306 ◽  
Author(s):  
Juliana C. Ferreira ◽  
Thiago M. Grabois ◽  
Gabrielle C.S. Calcado ◽  
Romildo D. Toledo Filho
Keyword(s):  
Mechanical Response ◽  
Construction And Demolition Waste ◽  
University Hospital ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Stress Strain ◽  
Natural Sand ◽  
Strain Behavior ◽  
Recycled Fine Aggregate

In this paper it was investigated how the use of recycled fine aggregate influences the stress-strain behavior of mortar mixtures with different strengths. The mix design composition of the studied mortars, expressed by mass, were 1:2:0.45, 1:4:0.68 and 1:6:1.05 (cement: sand: water/cement ratio). The substitution percentages by mass of the natural aggregate by recycled aggregate were 15, 25 and 50%. The recycled aggregate had a grain size distribution comparable to that of natural sand and was obtained by grinding the waste produced by the partial demolition of UFRJ’s University Hospital. The mortars were evaluated under uniaxial compressive strength test after 28 days of curing. The results indicated that for the two higher strength classes the substitution rates affects its mechanical response by decreasing the strength. Besides, for the lower strength class the recycled aggregate could promote an increase of strength in the case of 25% of replacement.

scholarly journals Durability of Structural Recycled Aggregate Concrete Subjected to Freeze-Thaw Cycles

2020 ◽  
Vol 12 (16) ◽  
pp. 6475 ◽  
Author(s):  
Caroline Santana Rangel ◽  
Mayara Amario ◽  
Marco Pepe ◽  
Enzo Martinelli ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Damage Level ◽  
Freeze Thaw

The increasing global demand for natural resources and the extensive production of construction and demolition waste (CDW) raise concerns for both the economic and environmental consequences that they can induce. Several efforts are being made with the aim to promote sustainable practices in the construction industry. In this context, one of the most relevant options refers to reusing CDW in new construction: specifically, the use of recycled concrete aggregate (RCA) is attracting a growing interest. Unfortunately, although the behavior of recycled aggregate concrete (RAC) has been widely investigated in the last few years, there are still knowledge gaps to fill on various aspects of the RAC performance, such as its durability in extreme conditions. The present study deals with the freeze-thaw performance of normal- (C35) and high-strength (C60) RAC produced with RCAs derived from different sources. Specifically, ten concrete mixtures were subjected to a different number of freeze-thaw cycles (namely, 0, 150 and 300), with the aim of analyzing the degradation of key physical and mechanical properties, such density, compressive strength, elastic modulus and tensile strength. Based on the obtained experimental results, a novel degradation law for freeze-thaw cycles is proposed: it unveils a relationship between open porosity of concrete, which is directly correlated to the peculiar properties of RCAs, and the corresponding damage level determined on RAC specimens.

scholarly journals Analysis of Compressive Fatigue Failure of Recycled Aggregate Concrete

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4620
Author(s):  
Fan You ◽  
Surong Luo ◽  
Jianlan Zheng ◽  
Kaibin Lin
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Cycle Fatigue ◽  
Demolition Waste ◽  
Aggregate Concrete

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.

Influence of Recycled Aggregate on the Rheological Behavior of Cement Mortar

2014 ◽  
Vol 600 ◽  
pp. 297-307 ◽  
Author(s):  
Paulo Roberto Lopes Lima ◽  
Romildo Dias Toledo Filho ◽  
Otávio da Fonseca Martins Gomes
Keyword(s):  
Yield Stress ◽  
Plastic Viscosity ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Cement Ratio ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Physical Tests

In this work it was studied the influence of recycled fine aggregate obtained from construction and demolition waste (CDW) on the rheological properties of Portland cement mortars. The CDW was initially separate in their main constituents (mortar, ceramic and concrete debris) at the laboratory and then grinded separately to the sand size in order to generate more homogeneous fine aggregates. The characterization of the natural and recycled sands was carried out through physical tests, X-ray diffraction, scanning electron microscopy (SEM), and image analysis (shape and texture description parameters). A conventional mortar and three mortars containing recycled sands were produced with a sand/cement ratio of 4 and consistency index of 255±5 mm. The consistency was kept constant by ranging the water-cement ratio from 0.58 to 1.14. The rheological study was performed using a rotating viscometer to obtain torque-rotation ratio and to calculate the yield stress and plastic viscosity. The results indicate that the presence of recycled aggregate causes a lowering of both yield stress and plastic viscosity with respect to the mortar containing natural aggregate.

scholarly journals Compressive Strength Study on the Freeze-thaw Resistance of Recycled Aggregate Concrete Members

2017 ◽  
Vol 11 (1) ◽  
pp. 270-280 ◽  
Author(s):  
Haicheng Niu ◽  
Yonggui Wang ◽  
Xianggang Zhang ◽  
Xiaojing Yin
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Surface Scaling

Introduction: Freeze-thaw resistance of recycled aggregate concrete with partial or total replacement of recycled aggregate compared with that of natural aggregate concrete was investigated in this paper. Method: Ninety specimens were fabricated to study the influence of different recycled aggregate replacement ratios on the surface scaling, mass loss, and residual compressive strength after 100 freeze-thaw cycles. Results: The experiment results indicate that the type of recycled aggregate and its replacement ratio have significant effects on the freeze-thaw performance. The cubic compressive strength of recycled aggregate concrete is overall slightly lower than that of normal concrete. After 100 freeze-thaw cycles, the compressive strength decreases and the reduction extent increases with increasing replacement rate of recycled aggregate. The surface scaling of reinforced recycled concrete prisms tends to be more severe with the increase of freeze-thaw cycles. Conclusion: Furthermore, a notable rise in mass loss and the bearing capacity loss is also found as the substitution ratio increases. Under the same replacement rate, recycled fine aggregate causes more negative effects on the freeze-thaw resistance than recycled coarse aggregate.

scholarly journals Bond Behavior Between Recycled Concrete Containing CDW and Different Types of Steel Bars

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Carine N. S. Reis ◽  
Paulo R. L. Lima ◽  
Mônica B. Leite
Keyword(s):  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Conventional Concrete ◽  
Recycled Fine Aggregate ◽  
Steel Bar ◽  
Internal Forces ◽  
Steel Rebars

The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete, which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements. The modification of the concrete composition, with the introduction of recycled aggregate from construction and demolition waste (CDW), affects the steel-concrete interface and can modify the bonding stress, which is also influenced by the type and diameter of the bar used. In this work, the influence of the recycled fine aggregate (RFA) and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test. Conventional concrete and recycled concrete, with RFA replacement level of 25%, were produced. Two types of steel rebars (i.e.,plain and deformed) with  diameters of 10.0 and 16.0mm were considered in this paper. The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate, but this trend is influenced by the diameter of the bar used. The use of ribbed bars modifies the stress bon-slip behavior, with an increase in the average bond strength, which is also observed with the reduction of the diameter of the bar.

Non Destructive Testing of Concrete with Recycled Cement Powder

2016 ◽  
Vol 825 ◽  
pp. 45-48 ◽  
Author(s):  
Tereza Pavlů ◽  
Magdaléna Šefflová
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Absorption Capacity ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Cement Powder

This study deals with determination of the physical properties of fine-aggregate concrete with partial replacement of cement in concrete mixture. Cement was replaced by recycled cement powder originating from construction and demolition waste. The main goal of this study is evaluation of the basic physical properties of the fine-aggregate concrete with partial cement replacement by recycled concrete powder such as density, water absorption capacity and capillary water absorption. The fine recycled concrete which was used as partial replacement of cement had the same grain size as cement. The replacement rate was 0 %, 5 %, 10 % and 15 %. Physical properties were investigated by using cubic and prismatic specimens.

scholarly journals Preliminary Analysis of the Use of Construction Waste to Replace Conventional Aggregates in Concrete

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
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Fine Aggregates ◽  
Mechanical Strengths

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.

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