Enhancing Mechanical Properties of High-Performance Concrete Using Steel Waste

Material characteristics	Cement
Specific surface area [m²/kg]	314
Water demand [%]	20
Start of setting [min]	110
End of setting [min]	160
Volume stability acc. to Le Chateliere [mm]	2
Compressive strength at 2 days [N/mm²]	28
Compressive strength at 28 days [N/mm²]	58
Tensile strength at 2 days [N/mm²]	5.4
Tensile strength at 28 days [N/mm²]	8.3

Table 2:

Chemical composition of cement and silica fume in [%]

Compound	Cement	Silica Fume
SiO₂	21.2	95
Al₂O₃	3.6	1.32
Fe₂O₃	4.41	0.85
CaO	63.66	0.55
MgO	1.22	0.70
SO₃	3.06	NA
K₂0	0.37	1.25
Na₂O	0.23	0.40
CI	0.08	NA
Loss on ignition	1.28	0.12
Insoluble matter	0.21	NA

Table 3:

Grading of fine aggregate

Sieve size	Passing [%]
10mm	100
4.75mm	92
2.36mm	81
1.18mm	73
600µm	55
300µm	24
150µm	7

(a) Steel waste from industrial districts, (b) Sieving of steel waste

Table 4:

Micro and hook fibres of steel characteristics

Product	Lengths, L [mm]	Diameters, D [mm]	Aspect proportion, L/D	Tensile strengths [MPa]
Micro steel fiber (WSF0213)	13	0.2	65	2860
Hooked fiber (KF 65/35)	35	0.55	64	2,200

(a) Micro steel fibers, (b) Hooked steel fibers

Table 5:

The Mixture proportions for HPC mixes

Symbol	C.[kg/m³]	S.[kg/m³]	S.F [kg/m³]	S.P [kg/m³]	W.[kg/m³]	Steel waste		Fiber
Symbol	C.[kg/m³]	S.[kg/m³]	S.F [kg/m³]	S.P [kg/m³]	W.[kg/m³]	[%]	[kg/m³]	[%]	[kg/m³]
S01	950	1050	190	40	205	0	0	1	78.5
S02								2	157
S03								3	235.5
S251		787.5				25	777.6	1	78.5
S252								2	157
S253								3	235.5
S501		525				50	1555.2	1	78.5
S502								2	157
S503								3	235.5
S751		262.5				75	2332.8	1	78.5
S752								2	157
S753								3	235.5
S1001		0				100	3110.4	1	78.5
S1002								2	157
S1003								3	235.5

* C. cement, S. Sand, S.F. silica Fume, SP. super plasticizer, and W. Water

** water/binder ratio, or water/cementitious materials = 0.22

HPC specimens (a) before casting, (b) after casting

Table 6:

Specimen's specifications

Test	Shape	Dimensions [mm]	Number
Compression	Cube	70×70	30
Compression	Cylinder	100×200	15
Splitting tensile	Cylinder	100×200	15
Flexural	Beam	40×40×160	15
Direct tension	Bone	50×75×460	15

Table 7:

Test results of mixtures

Symbol	Flowability (mini-slump test) [mm]	Compressive strength [MPa]			Tensile strength [MPa]			Hardened density [kg/m³]
		Cube [f_cu]		Cylinder [f^′_c]	Direct tensile [f_t]	Indirect (splitting) [f_sp]	Flexural [f_r]
		7days	28days	28days	Direct tensile [f_t]	Indirect (splitting) [f_sp]	Flexural [f_r]
S01	242	70.19	97.84	82.77	8.41	10.26	13.86	2470
S02	240.5	74.37	110.9	89.09	8.88	10.94	16.48	2478
S03	239	77.42	112.23	96.76	13.2	12.15	20.56	2490
S251	234	79.72	107.26	96.61	12	7.72	14.56	2550
S252	233.5	84.62	122.59	102.83	11.44	12.06	18.67	2658
S253	232	85.4	123.37	103.56	11.56	12.94	19.5	2740
S501	225.5	92.37	108.71	96.7	9.92	11.65	15.22	2795
S502	224.5	94.87	111.51	112.75	13.72	14.44	19.45	2900
S503	223	96.38	140.25	118.6	16.62	16.61	20.16	3030
S751	210	80.24	112.31	97.47	8.4	10.13	15.56	3100
S752	207.5	84.56	119.7	107.31	8.8	14.81	19.89	3300
S753	206	86.88	128.8	108.08	16.52	18.13	20.56	3390
S1001	205.5	76.68	107.35	79.99	6.3	10.93	18.22	3650
S1002	202	76.85	118.26	89.03	13.28	15.07	20.22	3690
S1003	200.5	78.24	126.73	108.59	14.8	19.7	20.89	3740

Compressive strength test of (a) cube specimen, (b) cylindrical specimen

Compressive strength results with 1% steel fibre

Compressive strength results with 2% steel fibre

Compressive strength results with 3% steel fibre

Percentage of changes in compressive strength of HPC mixtures

Specimen of splitting tensile strength test

Splitting tensile strength results with different ratio of steel fibre and steel waste

Percentage of change in indirect tensile strength of HPC mixes

Flexural strength results with different ratios of steel fibre and steel waste

Percentage of change in flexural tensile strength of HPC mixes

Direct tensile strength specimen. a) dog bone detail b) Direct tensile strength test

Direct tensile strength results with different ratio of steel fibre and steel waste

Percentage of changes in direct tensile strength of HPC mixes

SEM micrographs of HPC specimens. (a) 25% replacement of steel waste; (b) 50% replacement of steel waste; (c) 75% replacement of steel waste

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Articles in this issue

DOI: https://doi.org/10.2478/cee-2027-0010 | Journal eISSN: 2199-6512 (formerly 1336-5835) | Journal ISSN: 1336-5835

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Language: English

Submitted on: Apr 29, 2026

Accepted on: Jun 21, 2026

Published on: Aug 17, 2026

Published by: University of Žilina

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

High-performance concrete (HPC),

Steel waste,

Steel fibre,

Sustainability,

Mechanical properties,

Microstructure

Related subjects:

Business and economics,

Business management,

Industries,

Environmental management

© 2026 Ameer Ahmed Naji Al-Jamel, Rafea Flaih Hassan, published by University of Žilina
This work is licensed under the Creative Commons Attribution 4.0 License.

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Enhancing Mechanical Properties of High-Performance Concrete Using Steel Waste

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