Effects of recycled concrete aggregate on some mechanical properties of high strength concrete

The preparation of concrete mixtures can be tailored to provide wide range of mechanical and durability properties as well as to meet the design specifications of the structure. This paper discusses the potential use of recycled concrete aggregate in the production of high strength concrete. The effect of other processing parameters such as aggregate replacement ratio, type of admixture and slump height on the compressive strength and water absorption rate of different concrete mixes were investigated. The fabrication of high strength concrete was done by machine-mixing of the aggregates, cement and admixture in accordance with ASTM C192, utilizing the Taguchi design to derive the concrete mixtures. Using the 10% recycled fine aggregate with Mira P99 admixture and slump height of 4-6 inches showed an optimum condition and yielded a predicted maximum compressive strength at around 8400 psi. The failure mode of the concrete after compression test was generally shear fracture type. For the water absorption rate, only the admixture had a significant effect. Surface morphology of the fractured concrete surface revealed that utilizing recycled concrete aggregate resulted to a porous surface morphology compared to the natural aggregate.

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Mechanical Properties of Recycled Aggregate Self-Compacting High Strength Concrete Utilizing Waste Fly Ash, Cellular Concrete and Perlite Powders

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.13136 ◽

2019 ◽

Author(s):

Mohammed Abed ◽

Rita Nemes

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

High Strength Concrete ◽

High Strength ◽

Recycled Concrete ◽

Recycled Aggregate ◽

Partial Replacement ◽

Powder Materials ◽

Strength Concrete ◽

Cellular Concrete

The sustainability of engineering products has become a basic requirement instead of a mere choice because the harmony between economic activity and the earth’s ecosystem must be seriously considered. The influence of using three unprocessed waste powder materials as cement replacing materials (CRMs) and/or coarse recycled concrete aggregate (RCA) as a partial replacement of coarse natural aggregate (NA) on fresh and mechanical properties of self-compacting high-strength concrete (SCHSC) is investigated in this study. The activation index of the CRMs on the cement paste is tested as an initial step. The CRMs, namely, waste fly ash (WFA), waste perlite powder (WPP) and waste cellular concrete (WCC), are tested through 21 mixtures allocated by seven different series with three mixes of each. The mechanical properties of the 21 concrete mixes are determined after one, three and nine months of curing. Results of compressive strength, splitting tensile strength, flexural strength and modulus of elasticity are presented. This work shows that the mechanical and environmental performance of SCHSC can be improved by the replacement of NA by RCA of up to 50% and the replacement of cement by WPP or WFA of up to 15%. Using WCC is not recommended to be reached 15% and using WFA is preferable to be with incorporating RCA rather than NA alone. Findings indicate that incorporating waste materials can be valuable in SCHSC, thereby potentially leading to an increasingly green environment and paving the way for advancements in sustainable construction.

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The mechanical properties of brick containing recycled concrete aggregate and polyethylene terephthalate waste as sand replacement

E3S Web of Conferences ◽

10.1051/e3sconf/20183401001 ◽

2018 ◽

Vol 34 ◽

pp. 01001

Author(s):

Faisal Sheikh Khalid ◽

Nurul Bazilah Azmi ◽

Puteri Natasya Mazenan ◽

Shahiron Shahidan ◽

Noorwirdawati Ali

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Polyethylene Terephthalate ◽

High Strength ◽

Recycled Concrete ◽

Concrete Aggregate ◽

Recycled Concrete Aggregate ◽

Natural Sand ◽

Pet Waste ◽

Recycle Concrete Aggregate

This research focuses on the performance of composite sand cement brick containing recycle concrete aggregate and waste polyethylene terephthalate. This study aims to determine the mechanical properties such as compressive strength and water absorption of composite brick containing recycled concrete aggregate (RCA) and polyethylene terephthalate (PET) waste. The bricks specimens were prepared by using 100% natural sand, they were then replaced by RCA at 25%, 50% and 75% with proportions of PET consists of 0.5%, 1.0% and 1.5% by weight of natural sand. Based on the results of compressive strength, only RCA 25% with 0.5% PET achieve lower strength than normal bricks while others showed a high strength. However, all design mix reaches strength more than 7N/mm2 as expected. Besides that, the most favorable mix design that achieves high compressive strength is 75% of RCA with 0.5% PET.

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Roller Compacted Concrete with Recycled Concrete Aggregate for Paving Bases

Sustainability ◽

10.3390/su12083154 ◽

2020 ◽

Vol 12 (8) ◽

pp. 3154 ◽

Cited By ~ 2

Author(s):

Hedelvan Emerson Fardin ◽

Adriana Goulart dos Santos

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Modulus Of Elasticity ◽

Splitting Tensile Strength ◽

Recycled Concrete ◽

Concrete Aggregate ◽

Recycled Concrete Aggregate ◽

Roller Compacted Concrete ◽

Flexural Tensile Strength ◽

Mechanical And Physical Properties

This research aimed to investigate the mechanical and physical properties of Roller Compacted Concrete (RCC) used with Recycled Concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³ of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15.0 MPa at 28 days, splitting tensile strength above 1.9 MPa, flexural tensile strength above 2.9 MPa, and modulus of elasticity above 19.0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.

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