Numerical Simulation of Water Transport in Unsaturated Recycled Aggregate Concrete

Liu, Zhaolin; Zhang, Peng; Bao, Jiuwen; Hu, Yu

doi:10.3389/fmats.2020.560621

Cited by 9 publications

(3 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…e waste concretes were manually crushed using a small claw hammer crusher into recycled concrete aggregates. Water absorption increases with the size of aggregates because of an increase in adhered mortar on the RCA surface [37].…”

Section: Coarse Aggregatementioning

confidence: 99%

See 1 more Smart Citation

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

Odero¹,

Mutuku

Nyomboi³

et al. 2022

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

e use of concrete mixes with recycled materials has gained traction in research communities. However, the major drawback of the recycled concrete aggregate (RCA) has been the contribution of the cement paste mortar attached to the surface. e quantity of surface-attached mortar on the virgin aggregate dominates and de nes the shear performance of concrete beams. Concrete shear failure is usually abrupt and catastrophic, especially in concrete beams without shear reinforcement. e e ectiveness of the maximum size of RCA for the performance of untreated and treated with pozzolanic cement and rice husk ash (RHA) slurry was investigated. A total of sixteen ( 16) beams containing RCA of four (4) maximum sizes, 10, 14, 20, and 25 mm, were prepared and tested after 28 days. e beams were loaded in shear using shear span-depth ratios of 1.25 and 2.50. e results showed that the shear strength of the beams increases as the aggregate size increases to a maximum size of 20 mm, beyond which the shear strength reduces. It was attributed to the attached mortar, which increased as the size of the aggregate increased, creating a weak zone for shear failure in the concrete. In addition, RCA pretreatment using slurry-containing cement and RHA strengthened the attached mortar on the aggregate surface. It resulted in a dense and more compact aggregate that slightly improved the shear strength by about 2.2% for beams containing 20 mm RCA size. e ultimate shear strength of the experimental work in the study was predicted using eight (8) selected models from the literature. Models that account for the aggregate size and shear span to depth ratio resulted in shear strength ratios of 1.

show abstract

Section: Coarse Aggregatementioning

confidence: 99%

“…However, coarse RCA is characterized by more than one ITZ in RCA [11,37]. is area was found to be highly porous and mainly composed of a high amount of calcium hydroxide (C-H), other hydration products (calcium hydrate, ettringite), and unhydrated cement grains [38].…”

Section: Introductionmentioning

confidence: 99%

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

Odero¹,

Mutuku

Nyomboi³

et al. 2022

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

show abstract

“…Ahmad and Alghamdi [24] noted that the effect of the coarse aggregate type is very low when the strength of the mortar controls the compressive strength of the concrete mixture. Indeed, this is the case for normal concrete, but in the case of RCA, there is an additional interfacial transitional zone (ITZ) created due to the attached mortar [7,19,20,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Contribution of Surface Treatment on Physical and Mechanical Properties of Recycled Concrete Aggregates

Odero¹,

Mutuku

Nyomboi³

et al. 2022

Advances in Civil Engineering

View full text Add to dashboard Cite

The demand for virgin aggregates for concrete production worldwide has been increasing. At the same time, there is an increase in the production of rubbles from construction-related activities. The residues are produced either due to leftovers or from the demolished structures. However, worldwide, the utilization of recycled concrete aggregate (RCA) material for structural concrete has been limited, often considered inferior due to distorted surfaces. The problems with RCA arise because it is a composite aggregate made of natural aggregate and cement, and adhered surface mortar is the discontinuities on the surface that arise from the production technique or the strength of the original concrete. The development of hydrated calcium silicate binder in the concrete matrix has been the critical desire of researchers to make better concrete material. This research focuses on the treatment of RCA from locally available rice husk ash with minimum pozzolanic cement. The objective was achieved by conducting tests on the properties of aggregates that include specific gravity and water absorption, aggregate crushing value (ACV), and aggregate impact value (AIV). The effectiveness of the treatment technique is assessed by the analysis of SEM imagery and XRD analysis of the microstructure cement paste around the RCA. At 20% pozzolan concentration, RCA treatment yields comparable specific gravities, water absorption, ACV, and AIV. Furthermore, the replacement of 5% rice husk ash (in 20% concentration) provided the optimal proportion of treatment for RCA, resulting in a reduction of ACV by 31.4%, AIV by 30.0%, and water absorption by 12.7% compared to the untreated RCA. XRD showed that calcite (CaCO₃), quartz, and portlandite phases were the majority in the untreated RCA. The study indicates that pozzolanic cement with 15% can be used with 5% RHA to produce RCA with characteristics almost similar to virgin aggregates. This research presents a consistent methodology to achieve modified RCA for application in construction.

show abstract

Diffusion-reaction models for concrete exposed to chloride-sulfate attack based on porosity and water saturation

Zhuang,

Mu,

Guo

et al. 2024

Cement and Concrete Composites

View full text Add to dashboard Cite

Numerical Simulation of Water Transport in Unsaturated Recycled Aggregate Concrete

Cited by 9 publications

References 42 publications

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

Contribution of Surface Treatment on Physical and Mechanical Properties of Recycled Concrete Aggregates

Diffusion-reaction models for concrete exposed to chloride-sulfate attack based on porosity and water saturation

Contact Info

Product

Resources

About