Title:
Performance of Quality-Controlled Recycled Concrete Aggregates
Author(s):
Amit Kumar, Gyani Jail Singh, Priyanshu Raj, and Rajesh Kumar
Publication:
Materials Journal
Volume:
121
Issue:
1
Appears on pages(s):
17-30
Keywords:
durability; mechanical properties; mechanical treatment; performance; physical properties; quality control; recycled concrete aggregate (RA)
DOI:
10.14359/51740259
Date:
1/1/2024
Abstract:
This research examines the performance of quality-controlled
recycled concrete aggregates (QRAs) with fly-ash-based cement.
Compared to concrete made from untreated recycled concrete
aggregates (URC), quality-controlled recycled aggregate concrete
(QRC) has superior physical, mechanical, and durability properties.
Except for sorptivity, the physical, mechanical, and durability
properties of QRC are almost identical to those of natural
aggregate concrete (NC). The compressive strength, splitting
tensile strength, flexural strength, fracture energy, and modulus of
elasticity of QRC are higher than those of URC by 18.0%, 16.8%,
60.0%, 27.17%, and 43.46%, respectively. The abrasion resistance
of QRC is approximately 60% higher than URC. Scanning electron
microscope (SEM) image and energy-dispersive X-ray (EDX) analysis
prove that quality control produces denser old interfacial transition
zones (OITZ) with fewer microvoids. The QRA improves not
only the pore structure but also the weak mortar structure attached
to the aggregate. There is also a strong correlation between the
compressive strength and splitting tensile strength, flexural
strength, fracture energy, and modulus of elasticity of QRC. QRA
can be used to compute the mixture proportions for concrete
(certainly up to medium-strength concrete) according to either the
Indian standard or the international standard. It is challenging to
improve the sorptivity of recycled concrete aggregates closer to
NC. In addition, QRC has an initial sorptivity of two times (initial)
and a final sorptivity of 1.8 times higher than NC, whereas URC
has an initial sorptivity of 3.5 times (initial) and a final sorptivity of
2.35 times higher than NC.