Structural Behaviour of Hollow One-way Slabs of Recycled Concrete Aggregate with Rectangular Longitudinal Cavities for Sustainability: An Experimental and Numerical Study

Group	No.	Slab ID	Mix type	Slab type	Material proportions
Group	No.	Slab ID	Mix type	Slab type	Cement	Water	RCA	NCA	Fine aggregate	SP
I	1	SSR	MR	Solid	450	225	0	850	820	2.25
II	2	HS-R0	MR	Hollow	450	225	0	850	820	2.25
	3	HS-R25	M1	Hollow	450	225	212.5	675.5	820	4.5
	4	HS-R50	M2	Hollow	450	225	425	425	820	5.625
	5	HS-R75	M3	Hollow	450	225	675.5	212.5	820	6.75

Table 2:

Experimental test results of slab specimens

Slab ID	Mix type	f'_c MPa	f_spt MPa	Slab type	Experimental results				Failure type
					1^st cracking		Peak state
					P_cr, kN	Δ_cr, mm	P_p, kN	Δ_p, mm
SSR	MR	39.81	4.94	Solid	41.25	1.70	170.846	18.492	Flexure
HS-R0	MR	39.81	4.94	Hollow	31.57	1.98	148.686	18.864	Shear
HS-R25	M1	39.55	4.40	Hollow	37.84	1.04	148.182	12.17	Shear
HS-R50	M2	35.5	4.10	Hollow	35.04	0.94	135.762	10.723	Shear
HS-R75	M3	30.24	3.83	Hollow	27.34	1.30	111.078	15.779	Shear

Sieve analysis of the fine aggregate, normal coarse aggregate, and recycled concrete aggregate

Longitudinal and transverse sections of the hollow-core one-way slab

Arrangement of cavities in the slab to make a hollow-core one-way slab

The load mid-span deflection of the solid slab specimen, SSR

The ratio of the peak load of hollow specimens to that of the load of the solid specimen

The ratio of cracking to peak load of the first group of slab specimens

The load-deflection relationship of HS-R0

The load-deflection relationship of HS-R25

The load-deflection relationship of HS-R50

The load-deflection relationship of HS-R75

The simulation of Slab constituents via Abaqus

Table 3:

The material properties and parameters applied for simulating the hollow core slabs via Abaqus

Substance	Properties
Concrete	Modulus of elasticity, Ecc					Poisson's ratio
	Variable, according to the compressive strength					0.18
	Dilation angle		eccentricity	f_bo/f_co		Shape factor		Viscosity parameter
	32		0.1	1.16		0.67		1E-8
10 mm steel rebars		Yielding stress			Elastic modulus		Poisson's ratio
10 mm steel rebars		590 MPa			200000 MPa		0.3

Table 4:

FEA and experimental results of slab specimens at cracking and peak state

Slab ID	FEA results						Experimental Results
	1^st cracking		Peak state		Yield state		1^st cracking		Peak state
	Pcr, kN	Δcr, mm	Pp, kN	Δp, mm	Py, kN	Δy, mm	Pcr, kN	Δcr, mm	Pp, kN	Δp, mm
SSR	30.17	0.73	170.42	20.66	160.16	9.20	41.25	1.704	170.846	18.492
HS-R0	27.07	0.73	155.88	25.92	139.66	9.70	31.573	1.987	148.686	18.864
HS-R25	25.72	0.73	148.18	12.36	135.53	10.03	37.837	1.04	148.182	12.17
HS-R50	22.76	0.64	134.50	11.04	132.79	10.58	35.04	0.94	135.762	10.723
HS-R75	19.69	0.59	116.03	9.64	Not reached		27.34	1.304	111.078	15.779

[i] P = load, Δ = deflection, subscripts cr, y, and p refer to cracking, yield, and peak state, respectively.

The failure cracks of the solid slab, SSR

Shear failure of the hollow-core slab specimen, HS-R0

Shear failure of the hollow-core slab specimen, HS-R25

Shear failure of the hollow-core slab specimen, HS-R50

Shear failure of the hollow-core slab specimen, HS-R75

Table 5:

FEA results of slab specimens upon changing the reinforcement ratio

Slab ID	ρ= 0.499						ρ=1.248
Slab ID	Pcr	Δcr	Py	Δy	Pp	Δp	Pcr	Δcr	Py	Δy	Pp	Δp
SSR	27.02	0.732	101.51	8.21	109.22	25.08	30.17	0.73	160.16	9.20	170.42	20.66
HS-R0	23.95	0.718	87.41	8.18	95.29	21.74	27.07	0.73	139.66	9.70	155.88	25.92
HS-R25	21.58	0.684	83.33	8.29	90.45	20.70	25.72	0.73	135.53	10.03	148.18	12.36
HS-R50	20.35	0.638	81.76	8.35	88.73	20.97	22.76	0.64	132.79	10.58	134.50	11.04
HS-R75	17.46	0.594	77.63	8.56	83.75	21.54	19.69	0.59	not yield		116.03	9.64

[i] ρ is reinforcement ratio; Pcr= cracking load; Δcr= deflection at cracking load, Pp=peak load; Δp=deflection at peak load;

Load-deflection of solid slab, SSR for the two reinforcement ratios

Load-deflection of hollow core slab, HS-R0, for the two reinforcement ratios

Load-deflection of hollow core slab, HSR25, for the two reinforcement ratios

Load-deflection of hollow core slab, HS-R50, for the two reinforcement ratios

Load-deflection of hollow core slab, HS-R75, for the two reinforcement ratios

The second adopted parameter: change the void size by minimizing the length of the voids

Table 6:

FEA results of slab specimens upon changing the void size

Slab ID	Length of void = 500 mm						Length of void = 1700 mm
Slab ID	Pcr	Δcr	Py	Δy	Pp	Δp	Pcr	Δcr	Py	Δy	Pp	Δp
HS-R0	27.63	0.72	147.09	9.10	157.85	22.47	27.07	0.73	139.66	9.70	155.88	25.92
HS-R25	25.27	0.69	143.26	9.19	154.07	22.44	25.72	0.73	135.53	10.03	148.18	12.36
HS-R50	23.74	0.64	140.85	9.22	151.13	21.08	22.76	0.64	132.79	10.58	134.50	11.04
HS-R75	20.61	0.60	137.53	9.62	143.11	19.37	19.69	0.59	not yield		116.03	9.64

Load-deflection of hollow core slab, HS-R0, upon changing the voids' size

Load-deflection of hollow core slab, HS-R25, upon changing the voids' size

Load-deflection of hollow core slab, HS-R50, upon changing the voids' size

Load-deflection of hollow core slab, HS-R75, upon changing the voids' size

References

Authors

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Articles in this issue

DOI: https://doi.org/10.2478/cee-2027-0003 | Journal eISSN: 2199-6512 (formerly 1336-5835) | Journal ISSN: 1336-5835

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Language: English

Submitted on: Apr 12, 2026

Accepted on: May 1, 2026

Published on: Jun 25, 2026

Published by: University of Žilina

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

One-way hollow-core slab,

Recycled concrete aggregate,

Normal coarse aggregate,

Load-bearing capacity,

Finite element analysis,

Abaqus

Related subjects:

Business and economics,

Business management,

Industries,

Environmental management

© 2026 Zahraa Gheni Jebur, Adil Mahdi Jabbar, Thaar Saud Salman Al-Gasham, published by University of Žilina
This work is licensed under the Creative Commons Attribution 4.0 License.

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Structural Behaviour of Hollow One-way Slabs of Recycled Concrete Aggregate with Rectangular Longitudinal Cavities for Sustainability: An Experimental and Numerical Study

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