Effect of Mixed Recycled Aggregate on the Mechanical Strength and Microstructure of Concrete under Different Water Cement Ratios

Meng, Tao; Wei, Huadong; Yang, Xiufen; Zhang, Bo; Zhang, Yuncai; Zhang, Cungui

doi:10.3390/ma14102631

“…Several studies [22], [23] and [24] have shown that recycled construction aggregates show higher porosity than natural aggregates and the result from Fig. 15e and 15e' also confirms this.…”

Section: Microstructure Analysissupporting

confidence: 68%

Properties of Concrete Made from Cupola Furnace Slag and Recycled Construction Aggregates

Adese¹,

Olajide

²

,

Olaoyenikan³

2021

EJENG

1

0

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The replacement of traditional constituents of concrete with waste has garnered a lot of interest due to the increasing demand for natural resources used in concrete production. Hence, this study presents the outcome of an experimental investigation on the effect of partial replacement of Ordinary Portland Cement (OPC) at percentage levels of 0% to 25% in steps of 5%, partial and complete replacement of sand and granite in the percentage of 0 to 50 in steps of 10% with cupola slag and recycled construction aggregates. The fresh and hardened properties of concrete such as workability, compressive strength, and microstructural characteristics were assessed. The test results showed a decrease in workability as the percentage replacement of cupola furnace slag (CFS) and recycled construction aggregates (RCA) increases. Concrete produced at 28 days from the partial replacement of cement and sand with cupola slag has an optimum compressive strength of 20.37 N/mm2 at 10% and 22.81 N/mm2 at 20%, resulting in improved strength of 29.4% and 56.82%, respectively when compared with the control. In contrast, granite’s partial replacement with coarse cupola slag and complete replacement of sand and granite gave a lesser compressive strength when compared with the control samples at 7, 14, 28, and 56 days. The porosity of the concrete with optimum compressive strength from each mix was studied using microscopic and image analysis. The result showed that the addition of cupola slag in granulated and fine forms decreases the porosity, hence leading to higher compressive strength.

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“…Several studies [22], [23] and [24] have shown that recycled construction aggregates show higher porosity than natural aggregates and the result from Fig. 15e and 15e' also confirms this.…”

Section: Microstructure Analysissupporting

confidence: 62%

Properties of Concrete Made from Cupola Furnace Slag and Recycled Construction Aggregates

Adese¹,

Olajide

²

,

Olaoyenikan³

2021

EJ-ENG

0

View full text Add to dashboard Cite

The replacement of traditional constituents of concrete with waste has garnered a lot of interest due to the increasing demand for natural resources used in concrete production. Hence, this study presents the outcome of an experimental investigation on the effect of partial replacement of Ordinary Portland Cement (OPC) at percentage levels of 0% to 25% in steps of 5%, partial and complete replacement of sand and granite in the percentage of 0 to 50 in steps of 10% with cupola slag and recycled construction aggregates. The fresh and hardened properties of concrete such as workability, compressive strength, and microstructural characteristics were assessed. The test results showed a decrease in workability as the percentage replacement of cupola furnace slag (CFS) and recycled construction aggregates (RCA) increases. Concrete produced at 28 days from the partial replacement of cement and sand with cupola slag has an optimum compressive strength of 20.37 N/mm2 at 10% and 22.81 N/mm2 at 20%, resulting in improved strength of 29.4% and 56.82%, respectively when compared with the control. In contrast, granite’s partial replacement with coarse cupola slag and complete replacement of sand and granite gave a lesser compressive strength when compared with the control samples at 7, 14, 28, and 56 days. The porosity of the concrete with optimum compressive strength from each mix was studied using microscopic and image analysis. The result showed that the addition of cupola slag in granulated and fine forms decreases the porosity, hence leading to higher compressive strength.

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“…ported by the literature [20,21]. Moreover, the role of hydrogen peroxide in modulating pore size is noteworthy.…”

Section: Microstructurementioning

confidence: 93%

Enhancing Water Resistance in Foam Cement through MTES-Based Aerogel Impregnation

Li,

Yao,

Wang

et al. 2024

Gels

1

0

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The propensity of foamed concrete to absorb water results in a consequential degradation of its performance attributes. Addressing this issue, the integration of aerogels presents a viable solution; however, their direct incorporation has been observed to compromise mechanical properties, attributable to the effects of the interface transition zone. This study explores the incorporation of MTES-based aerogels into foamed cement via an impregnation technique, examining variations in water–cement ratios. A comprehensive analysis was conducted, evaluating the influences of MTES-based aerogels on the thermal conductivity, compressive strength, density, chemical composition, and microstructure of the resultant composites across different water–cement ratios. Our findings elucidate that an increment in the water–cement ratio engenders a gradual regularization of the pore structure in foamed concrete, culminating in augmented porosity and diminished density. Notably, aerogel-enhanced foamed concrete (AEFC) exhibited a significant reduction in water absorption, quantified at 86% lower than its conventional foamed concrete (FC) counterpart. Furthermore, the softening coefficient of AEFC was observed to surpass 0.75, with peak values reaching approximately 0.9. These results substantiate that the impregnation of MTES-based aerogels into cementitious materials not only circumvents the decline in strength but also bolsters their hydrophobicity and water resistance, indirectly enhancing the serviceability and longevity of foamed concrete. In light of these findings, the impregnation method manifests promising potential for broadening the applications of aerogels in cement-based materials.

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Effect of Mixed Recycled Aggregate on the Mechanical Strength and Microstructure of Concrete under Different Water Cement Ratios

Cited by 15 publications

References 40 publications

Properties of Concrete Made from Cupola Furnace Slag and Recycled Construction Aggregates

Properties of Concrete Made from Cupola Furnace Slag and Recycled Construction Aggregates

Properties of Concrete Made from Cupola Furnace Slag and Recycled Construction Aggregates

Enhancing Water Resistance in Foam Cement through MTES-Based Aerogel Impregnation

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