Effect of Water Reducing Admixtures and Construction Variability in Concrete Containing Recycled Aggregate Concrete

2021 ◽  
Vol 47 (3) ◽  
pp. 456-464
Author(s):  
Claude Villiers
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Target Strength ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Effect Of Water ◽  
Concrete Mixtures ◽  
Concrete Mix

The objectives of this project are to evaluate the effect of water reducing admixtures and construction variability in concrete mixtures containing recycled concrete aggregate (RCA). A concrete mix that was approved for curbs and sidewalks in the State of Florida was selected. Based on the analysis conducted, it was found that properties of the RCA were comparable to the virgin aggregate used in this project. However, the absorption of the RCA was double as compared to the limestone. Although the compressive strength of the virgin mix was decreased by 19% when RCA was introduced into the mix, both mixes met the target strength (17.2 MPa). Admixture has a significant impact on all the mixes, especially on mixes that contained RCA. When admixture was omitted, the 28-day compressive strength dropped to nearly 55% on the mixture containing RCA. In addition, the RCA mix without the admixture did not reach the target strength at 28 days. Similarly, construction variability has a significant effect on the compressive strength of the mixes. When the RCA content was increased by 15% and 25% respectively, the concrete paste was weak. These mixtures did not meet the target strength at 28 days.

scholarly journals Influence of bagasse ash and recycled concrete aggregate on hardened properties of high-strength concrete

2018 ◽  
Vol 68 (330) ◽  
pp. 158 ◽  
Author(s):  
P. Rattanachu ◽  
I. Karntong ◽  
W. Tangchirapat ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt
Keyword(s):  
Compressive Strength ◽  
Negative Impact ◽  
Pore Space ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Crushed Limestone

This research aimed to use of bagasse ash as a cement replacement in high-strength recycled aggregate concrete (HS-RAC). Crushed limestone was replaced with 100% recycled concrete aggregate (RCA) and the ground bagasse ash (GBA) was used to partially replace ordinary Portland cement (OPC) at 20, 35 and 50%wt of binder to cast HS-RAC. The results indicated that the replacing of crushed limestone with RCA had a negative impact on the properties of the concrete. Increasing the amount of GBA in HS-RAC resulted in a decrease in density and an increase in the volume of permeable pore space. The concrete mixtures prepared with 20%wt GBA replacement of OPC promoted greater the compressive strength than the conventional concrete (CT concrete) at 90 days or more. HS-RAC with GBA (up to 50%) was more durable in terms of chloride ion penetration resistance, although it had lower compressive strength than the CT concrete.

Mechanical Properties of Concrete Using Treated Recycled Concrete Aggregate in Marine Environment

2020 ◽  
Vol 841 ◽  
pp. 138-143
Author(s):  
Sallehan Ismail ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Marine Environment ◽  
Impact Resistance ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Curing Conditions

This study also investigates the effectiveness of multiple surface modification of recycled concrete aggregate (RCA) with respect to mechanical properties of the resultant recycled aggregate concrete (RAC) when exposed to various curing conditions, namely, normal water (Nw) and seawater (Sw). The properties included compressive and flexural strength and impact resistance. Findings show that effect inclusion of the treated coarse RCA is significant in enhancing the mechanical properties of RAC. The exposure to Sw appears to affect the degradation of the compressive strength of RAC remarkably in a marine environment. In this case, however, using of treated RCA is found beneficial in decreasing the deterioration in the compressive strength of RAC.

scholarly journals Compressive Strength of Concrete with Recycled Concrete Aggregate as Coarse Aggregate and Recycled Paving Block Aggregate as Fine Aggregate Partially Substituted by Recycled Brick Aggregate

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Idi Priyono ◽  
Meiske Widyarti, Erizal
Keyword(s):  
Compressive Strength ◽  
Residential Buildings ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Concrete Mix

An excessive extraction of natural resources for aggregate in concrete mix can caused an environmental degradation.  According to Indonesia ministry of industry in 2017, the use of cement is predicted will reach 84,96 million tons, that can affected the use of aggregate for concrete mix are quadruplet to 250 – 350 million tons. Opimally, the use of recycled material is green method that can reduce an excessive extraction of natural aggregates and keep an environmental sustain. The aim of this study is to obtain recycled aggregate concrete compressive strength and examine recycled aggregate concrete quality in days 3, 7, 28, 35, and 90 along with a proposal of the use of recycled aggregate concrete as a building construction material. This research used experimental method of SNI 03-2834-2002 the standard of normal concrete mix design for f’c 25 MPa then built five types of concrete mix of REC B, REC C, REC D, REC E, and REC F with every types of concrete has four sample are used for compressive strength test. The fine recycled paving block aggregate (RPA) were used partially to substituted a fine recycled brick aggregate (RBA) at 0%, 25%, 50%, 75%, and 100% by weigth. The result of this study showed the mixed concrete REC D with RCA 100%, RPA 50% and RBA 50% in 28 days is generate highest compressive strength than other recycle aggregates concrete mixes. Compressive strength at 28 days in a mix codes REC B, REC C, REC D, REC E and REC F are 18,12 MPa; 18,36 MPa; 19,35 MPa;16,69 MPa; and 16,39 MPa. The results show that it is feasible to replace a natural aggregate entirely by recycled aggregates. With compressive strength over 17 MPa at 28 days, mix codes REC B, REC C and REC D are recommended to use the recycled aggregate concrete for structure of residential buildings but mix codes REC E and REC F aren’t recommended and only allowed for non-structural concrete such as separate wall (SNI 8140:2016). Based on SNI 03-0691-1996 about solid brick concrete (paving block), recycle aggregate concrete with mix code of REC B, REC C, and REC D are able to use on paving block with B quality such as parking lot. While, recycled aggregate concrete with mix code of REC E and REC F are able to use on paving block with C and D quality which used for pedestrian, garden and other use. 

Thermal Properties of Concrete with Recycled Aggregate

2014 ◽  
Vol 1054 ◽  
pp. 227-233 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Martin Volf ◽  
Tereza Pavlů
Keyword(s):  
Thermal Properties ◽  
Building Materials ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Conventional Concrete ◽  
Concrete Mixtures ◽  
Reference Mixture

Currently, the emphasis is put on sustainable buildings; simultaneously, the emphasis is put on energy efficiency in buildings, with respect to this fact of necessity to test thermal properties of new building materials. This article deals with the thermal properties of concrete containing recycled concrete aggregate. Four types of recycled concrete aggregate were used for the production of the concrete. For the testing of concrete, a total of ten concrete mixtures were made, one of which was a reference mixture and the natural aggregate was replaced by recycled aggregate of varying ratio in the other mixtures. Finally, it is possible to say that according to the thermal properties of the recycled aggregate concrete is possible to be used in the same applications as conventional concrete.

Critical Analysis of Recycled Aggregate and Concrete with Recycled Aggregate

2011 ◽  
Vol 99-100 ◽  
pp. 1274-1280
Author(s):  
Neela Deshpande ◽  
S.S Kulkarni
Keyword(s):  
Compressive Strength ◽  
Critical Analysis ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Waste Materials ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Mix

One of the construction sector's major contributions to the preservation of the Environment and sustainable development is the reuse and recycling of the waste materials it generates (reducing, reusing, recycling and regenerating the residues that originate the constructive activity). With this view an experimental program was undertaken which helped in judging the effectiveness of using Recycled aggregate in concrete ,by assessing the properties of Recycled aggregates – Coarse and Fine. Further with the guidance of IS 10262:2009 ,Concrete mix was designed for 28 day compressive strength as 25N/mm2 using conventionally used aggregates and Recycled aggregates. From economy perspective an attempt was made to use superplasticser to reduce cement consumption. With reference to the experimental results, analysis of important properties of both the types of concrete is done and the suitability of use of recycled concrete aggregate for new concrete is judged.

Recycling of Waste Concrete and Fly Ash for Recycled Aggregate Concrete: Fundamental Characteristics Evaluation

2009 ◽  
Vol 620-622 ◽  
pp. 255-258 ◽  
Author(s):  
Cheol Woo Park
Keyword(s):  
Fly Ash ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Recycled Concrete Aggregate ◽  
Aggregate Concrete ◽  
Waste Concrete

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.

scholarly journals The influence of recycled concrete aggregate on the properties of concrete

2018 ◽  
Vol 162 ◽  
pp. 02020 ◽  
Author(s):  
Nisreen Mohammed ◽  
Kaiss Sarsam ◽  
Mazin Hussien
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Modulus Of Rupture ◽  
Concrete Aggregate ◽  
Hardened Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregates

Use of Recycled Coarse Aggregate (RCA) in concrete can be described in terms of environmental protection and economy. This paper deals with the mechanical properties of concrete compressive strength, splitting tensile strength, modulus of elasticity, and modulus of rupture. Three kinds of concrete mixtures were tested, concrete made with Natural Coarse Aggregate (NCA) as a control concrete and two types of concrete made with recycled coarse aggregate (50% and 100% replacement level of coarse recycled aggregate). These kinds of concrete were made with different targets of compressive strength of concrete f ’c (35MPa) and (70 MPa). Fifty specimens were tested of the fresh and hardened properties of concrete. The waste concrete from laboratory test cubes was crushed to produce the Recycled Coarse Aggregate used in recycled concrete. A comparative between the experimental results of the properties for fresh and hardened concrete is presented in the paper. Recycled aggregate concrete (RCA) had a satisfactory performance despite the replacement ratios. It was found using the size of Recycled Coarse Aggregate (RCA) of (5-14) mm has quite similar in performance with the same size of Natural Coarse Aggregate (NCA), it is necessary to use high quality of recycled concrete (with low levels of impurities). Recycled aggregate as an alternative to natural aggregates -seems quite successful.

Resistance to Chloride Penetration of Recycled Aggregate Concrete Modified Using Treated Coarse Recycled Concrete Aggregate and Fibres

2020 ◽  
Vol 991 ◽  
pp. 101-108
Author(s):  
Sallehan Ismail ◽  
Mahyuddin Ramli
Keyword(s):  
Chloride Penetration ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Coupling Effects ◽  
Aggregate Concrete ◽  
Curing Regimes ◽  
Coarse Recycled Concrete Aggregate

This paper presents a study that aimed to assess the chloride penetration depth of recycled aggregate concrete (RAC) modified by using treated coarse recycled concrete aggregate (RCA), adding polyolefin (PO) or polypropylene (PP) fibre and comparing with normal concrete. The coupling effects of the treated RCA and fibres on the chloride penetration of RAC were analysed after two different curing regimes (i.e. normal and seawater) and tested at different curing ages (i.e. 90, 180 and 300 days). Results showed that the inclusion of treated coarse RCA can reduce porosity, thereby decreasing the chloride penetration of RAC. However, the coupling effects of treated coarse RCA and fibre, especially on the use of PO fibre, can enhance the results.

Properties of Dry-Mortar with Recycled Concrete Aggregate and Powder of Crushed Clay Bricks

2011 ◽  
Vol 374-377 ◽  
pp. 1637-1640
Author(s):  
Jian Hua Xue ◽  
Xiao Guang Li ◽  
Yun Xiao Liu ◽  
Qiang Du
Keyword(s):  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Mass Ratio ◽  
Clay Brick ◽  
Natural Sand ◽  
Clay Bricks

Recycled concrete aggregate (RCA) and crushed clay bricks (CCB) have been increasingly researched and used in past two decades. However, studies focusing on the properties of dry-mortar with RCA and CCB are very limited. In this research, results from physical and mechanical properties of recycled mortar with fine recycled aggregate (FRA), fine recycled powder (FRP) and crushed clay brick (CCB) were secured. It is shown that sinking degree of FRA mortar can be adjusted in the range of 70-90mm and their water-maintainability is superior to natural sand mortar. However, compressive strength of FRA mortar at various ages decrease, compared to natural sand mortar under the condition of same mixed proportion. Compressive strength of FRA mortar is above 5.0MPa with mass ratio of aggregate to cement lower than 6.0.Workability of FRP and CCB mortar is similar to fly ash mortar and their apparent densities are under the 2.0g/cm3. Compressive strength of FRP and CCB mortar is near to 8.5 MPa at 28 days of age.

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