Restrained Shrinkage Tests Research Articles

Performance of capsules in self-healing early-age concrete due to restrained shrinkage

Performance of capsules in concrete was evaluated numerically using a simulated ASTM C1581 restrained shrinkage test and experimentally measured concrete shrinkage strain data to determine their effectiveness in healing cracks in early-age concrete. The model accounts for the concrete’s time-dependent mechanical properties, and the capsule’s geometrical and mechanical properties, and depth. A finite element model was developed to simulate the concrete volume change due to autogenous and drying shrinkage and the corresponding state of stress, and fracture mechanics to trace crack initiation and propagation in a restrained shrinkage ring. The performance of capsules in self-healing early-age concrete was found to depend on the capsules’ geometry, the stiffness ratio of concrete-to-capsule, and bond strength-to-rupture strength ratio of concrete-to-capsule. Results reveal that corresponding ratios of concrete effective stiffness and bond strength at 28 days to the stiffness and rupture strength of the capsules provide a threshold limit after which capsules debond in self-healing early-age concrete.

Effect of super absorbent polymer mixing method on shrinkage performance of cast-in-place concrete confined by existing concrete

To study the effect of different super absorbent polymer (SAP) mixing methods on mechanical and shrinkage properties of internal curing concrete, SAP mixing mode was used as the study variable, and simulated the bridge leveling structure. The flow performance test, mechanical performance test, free shrinkage test, restrained shrinkage test and scanning electron microscope observation test were carried out on the internal curing concrete. The influence of different mixing methods on the flow properties, mechanical properties, shrinkage properties and microstructure of internal curing concrete were analyzed. The results showed that the amount of mixing water had a great influence on the fluidity when adding pre-absorbent SAP; The effect of SAP on the mechanical properties is minimal when the dosage is 0.2% of the mass of cementing material; Pre-absorbent SAP has the best effect on improving shrinkage cracks of concrete; SAP stored water at the initial stage of hydration, promoted the generation of hydrolysis products, prolong the hydration process, filled the gap inside the concrete, and improved the anti-cracking performance. It is recommended that SAP should be partially pre-absorbed.

Influence of Glass Microfibers on the Control of Autogenous Shrinkage in Very High Strength Self-Compacting Concretes (VHSSCC)

High-performance concrete (HPC) is widely used in infrastructure for its durability and sustainability benefits. However, it faces challenges like autogenous shrinkage, leading to potential cracking and reduced durability. Fiber reinforcement offers a solution by mitigating shrinkage-induced stresses and enhancing concrete durability. In this sense, this study investigates the use of glass microfibers to mitigate autogenous shrinkage and early-age cracking in high-strength self-compacting concrete. Samples were prepared with two water-to-binder ratios (w/b): 0.25 and 0.32; and three glass microfiber contents: 0.20%, 0.25%, and 0.30 vol.%. The concrete mixtures were characterized in the fresh state for slump flow and in the hardened state for compressive strength, static, and dynamic Young’s modulus. Unrestrained and restrained shrinkage tests were also conducted in the seven days-age. The findings revealed that glass microfibers reduced the workability in mixtures with lower slump flow values (w/b of 0.25), while less viscous mixtures (w/b of 0.32) exhibited a slight improvement. Compressive strength showed a proportional enhancement with increasing fiber contents in concretes with a w/b ratio of 0.32. A contrasting trend emerged in concretes with a w/b ratio of 0.25, wherein strength diminished as fiber additions increased. The modulus of elasticity improved with fiber additions only in the matrix with a w/b ratio of 0.25, showing no correlation with compressive strength results. In shrinkage tests, the addition of glass microfibers up to specific limits (0.20% for a w/b ratio of 0.25 and 0.25% for w/b of 0.32) demonstrated improvements in controlling concrete deformation in unrestrained shrinkage analyses. Concerning cracking reduction in restrained concrete specimens, the mixtures did not exhibit significant improvements in crack prevention.

Increasing the Length of Concrete Pavement Slabs Using Shrinkage Reducing Admixture and Polypropylene Fiber

Pavement engineers frequently employ concrete pavements because of their benefits such as extended lifetime, superior performance and durability, and so on. However, there are some disadvantages of these pavements such as shrinkage which may lead to cracking, warping, and limiting the length of the concrete pavement slabs. Shrinkage reducing admixture (SRA) and polypropylene fibers can be employed to prevent or control shrinkage cracking. In this study, increasing the length of concrete pavement slabs using shrinkage reducing admixture and polypropylene fiber was investigated. For mix compositions, two water–cement ratios of 0.35 and 0.4 were employed, and the percentages of SRA and polypropylene fiber utilized in mixes were 2% and 1% by weight of cement, respectively. Slump, compressive strength, third point flexural strength, electrical resistance, free and restrained shrinkage tests were carried out as the experimental programming to investigate the effect of these materials on concrete behavior and evaluate the amount of concrete pavement design parameters. Statistical analysis and RSM were used to determine the significance of each parameter and their interactions on concrete properties. It was observed that the use of SRA had no influence on workability; however, polypropylene fibers reduced the slump flow of concrete. Also, the use of SRA resulted in a decrease in mechanical properties. In addition, the use of polypropylene fibers considerably enhanced the energy absorption of concrete. Furthermore, on concrete containing SRA and polypropylene fiber, the magnitude of free and restrained shrinkage and crack width were reduced. Finally, the length and thickness of concrete pavement slabs were evaluated using the experimental results on the Tehran-Shomal freeway as a case study. The slab length could be increased by about 20% without any significant change in the slab thickness using SRA and polypropylene fiber in concrete mix composition. This can lead to an increase in construction speed, improve the durability of pavement and generally increase the quality of the concrete pavement.

Evaluation of Desiccation Behavior in Basalt Microfiber–Reinforced Bentonite Clay for Geological Repositories of Nuclear Spent Fuel Using Digital Image Correlation

Abstract Secure storage of nuclear spent fuel (NSF) is of great concern for protecting public health and safety. The preferred long-term solution is underground containment in geological repositories, where one or more engineered barrier materials (EBM) encapsulate the NSF and separate it from the natural rock. Bentonite clay is commonly used as an EBM due to its many advantageous properties including low hydraulic conductivity, which ensures limitation of water infiltration to the system and the subsequent risk of corrosion in NSF canisters. However, bentonite clay subjected to heating from nuclear decay may form desiccation cracking. This study conducted disk-shaped free shrinkage tests and ring-shaped restrained shrinkage tests of bentonite clay samples reinforced with basalt microfibers. Digital image correlation was used as a noncontact full-field displacement measurement to track the time-evolving shrinkage and desiccation cracking phenomena and make quantified comparisons between plain bentonite and bentonite with varying contents of basalt microfibers (i.e., 0.0, 0.5, 1.0, and 1.5 % wt.). Results indicate that plain bentonite and basalt microfiber-reinforced samples showed similar free shrinkage behavior, while desiccation cracking behavior was significantly altered by adding basalt microfibers. Microfiber reinforcement effectively reduced major cracks through a “crack-bridging” effect while causing minor cracks to initiate earlier and at higher moisture contents than plain bentonite. Results infer that reinforcing plain bentonite with inorganic microfibers can potentially control desiccation cracking, leading to safer and improved nuclear waste management.

Investigation on cracking resistance mechanism of basalt-polypropylene fiber reinforced concrete based on SEM test

In order to study the anti-crack mechanism of basalt-polypropylene fiber reinforced concrete (BPFRC), based on the restrained shrinkage test of BPFRC, the anti-crack enhancement mechanism of basalt fiber and polypropylene fiber was discussed through SEM microscopic test, and the sensitivity index of BPFRC's anti-crack performance was studied by combining grey relational theory and entropy weight method. The results show that basalt fiber has a significant inhibitory effect on the initiation and propagation of micro-cracks, and polypropylene fiber has a more obvious inhibitory effect on the propagation of macro-cracks. Mixing basalt fiber and polypropylene fiber into concrete can improve the pore structure of concrete matrix, reduce the initial defects of concrete matrix, enhance the density of the interface transition zone between aggregate and matrix, make concrete play a bridging role in different stages of stress deformation, and enhance the crack resistance of concrete more significantly. Grey relational theory combined with entropy weight method shows that the splitting tensile strength has the most significant influence on the crack resistance of BPFRC. This study can provide a new method for the sensitivity index analysis and crack resistance evaluation of concrete.

Experimental evaluation of alkali-activated and portland cement-based mortars prepared using waste glass powder in replacement of fly ash

The decreasing trend in coal fly ash production has led to a rapidly growing interest in finding alternative materials to replace fly ash in concrete. In this study, the use of glass powder to replace fly ash in concrete was investigated. The performance of portland cement and alkali-activated slag-based mortars containing fly ash (class F) or glass powder (aluminosilicate-based) was evaluated via a series of experiments, including fresh, physical, mechanical, and restrained cracking tests. Notably, a customized restrained shrinkage test was used to investigate the cracking potential. Results showed that the ultra-fine glass powder performed differently in the two binding systems. In the portland cement system, the use of glass powder yielded higher concrete mechanical performance compared to the concrete containing fly ash, while the opposite conclusion was obtained for the alkali-activated system. Comparing the alkali-activated system with the portland cement system, the alkali-activated materials with either fly ash or glass powder had higher free shrinkage and developed cracks much earlier under the restrained drying shrinkage. However, the alkali-activated materials maintained a high level of strain in the steel ring, which was primarily attributed to the development of multiple cracks and their different bonding at the mortar and steel interface.

Effect of microfibers or SRA on the shrinkage and mechanical properties of alkali activated slag/fly ash-based mortars incorporating recycled fine aggregate

Alkali activated slag and fly ash (AASF) systems present satisfactory mechanical properties compared to portland cement systems; however, the high shrinkage and cracking potential of these binders require preventive strategies. Furthermore, to improve the sustainability of such systems, using recycled fine aggregate (RFA) in concrete or mortar can help reduce the problem of depletion of aggregate reserves and disposal of laboratory concrete wastes. This study aims to evaluate the shrinkage characteristics of AASF mixtures incorporating RFA reinforced with polypropylene (PP) or steel fiber (SF) or containing shrinkage reducing admixture (SRA). In this regard, the compressive and uniaxial tensile strength and drying, autogenous, and restrained shrinkage properties of AASF mortars containing RFA were studied. Furthermore, in order to investigate the effect of RFA, natural sand was replaced with RFA by 20%, and as a result of this replacement, a slight decline in mechanical properties and free shrinkage was observed. The inclusion of microfibers enhanced the tensile strength of mortars, and the utilization of 0.6% microfibers reduced the drying and autogenous shrinkage of mixtures up to 20% and 15%, respectively, while the incorporation of 0.3% of microfibers was insufficient to reduce the free shrinkage. The addition of 1.5 and 3% SRA significantly decreased the drying and autogenous shrinkage up to 28% and 53% compared to the reference mixture, respectively. The restrained shrinkage test results indicated that incorporating microfibers or SRA extended the crack initiation time up to 6.4 and 14.6 times compared to the reference. The stress rate and crack width values of mortars decreased by 74% and 91% with the inclusion of 0.6% microfibers or 3.0% SRA, respectively. The overall test results showed that AASF mixtures incorporating 0.6% SF, 0.6% PP fiber, or 3% SRA exhibited satisfactory results in terms of shrinkage properties without compromising the mechanical performance.

Investigation on early-age cracking resistance of basalt-polypropylene fiber reinforced concrete in restrained ring tests

The restrained shrinkage deformation of concrete structures at an early age is the main reason for cracking. Basalt-polypropylene fiber can reduce the shrinkage strain and cracking potential of concrete effectively. Investigation on cracking resistance of basalt-polypropylene fiber reinforced concrete (BPFRC) at early age by restrained ring test remain lacking. This study conducted free shrinkage test and restrained shrinkage test to analysis the early-age cracking resistance of BPFRC. The experimental results showed that incorporating basalt fiber and polypropylene fiber into concrete could decrease the free shrinkage and restrained shrinkage of concrete matrix and reduce the maximum theoretical elastic stress, actual maximum residual stress and relaxed stress, among which, the better positive effect was achieved when basalt fiber and polypropylene fiber hybridized. A numerical finite element simulation model was successfully carried out to predict the time-dependent maximum tensile stress in the concrete ring. Importantly, the damage evaluation of restrained shrinkage concrete ring was investigated based on the relations of the compressive (dc) and tensile (dt) damage factors with inelastic strains of BPFRC proposed in this paper, and a good agreement between simulation and experimental test had been observed. The findings in this study would promote the development and application of BPFRC.

Assessing the relaxation of recycled aggregates concrete from free and restrained shrinkage tests

Recycled concrete aggregates (RCA) lead to higher shrinkage of concrete than natural aggregates because of two main reasons: lower elastic modulus and possible shrinkage of RCA. The study aims at quantifying the effects of both phenomena, thus Trisphere model has been chosen as it takes into account the influence of aggregates modulus and shrinkage on the properties of concrete. The existing model has been adapted to determine the elastic modulus and shrinkage of recycled aggregates from the modulus and shrinkage of concrete. The shrinkage of coarse RCA was much lower than the shrinkage of fine RCA, thus the increase in the shrinkage of concrete can be mainly attributed to the reduction in aggregate modulus and variations of composition parameters (W/C, volume of paste). The model also allows estimating the delayed elastic modulus of concrete. The obtained values are compared with the numerical determination of viscoelastic-aging Young's modulus from restrained shrinkage tests (ring tests). The long-term moduli provided by both approaches are consistent for most of studied materials. The relaxation increased with the content of coarse recycled aggregates, but the variation was lower than reported in creep studies. This could be due to lower relative stress level as recycled aggregates also induce lower elastic modulus thus lower stress for a given restraint.

Shrinkage performance of concrete for shotcrete use restrained by rock in hot and dry tunnel environment

The shotcrete shrinks greatly in the hot and dry environments, and the shotcrete is easy to crack or even debond under the restraint of the surrounding rock. In this context, a concrete-rock restrained shrinkage test device is used to study the shrinkage performance of concrete in the hot and dry environments of 80 °C, and the inhibitory effect of steel fiber and shrinkage reducing admixture on concrete shrinkage is explored. A concrete-rock restrained shrinkage mechanics model is established to calculate the interfacial restraint force and the distribution of stress and strain on the concrete section. The results show that the concrete expands at the initial stage under hot and dry environments, but the shrinkage of the concrete increases rapidly with the increase of age, and the growth rate slows down after a certain age and finally stabilizes. With the increase of the distance to the bonding surface, the shrinkage deformation of concrete increase continuously, and the stress distribution transitions from the tensile stress zone to compressive stress zone. The end-hook steel fiber and shrinkage reducing admixture can significantly reduce the shrinkage deformation and interfacial restraint force of concrete.

Preliminary Exploration of Economic Polypropylene-Fiber-Reinforced ECC with Superfine River Sand (SSPP-ECC) Applied to a Bridge Pavement Leveling Overlay.

In response to the current common disease of concrete leveling overlays of bridge pavement in China, the feasibility of using an economic SSPP-ECC with local waste superfine sand as an alternative material for a leveling overlay was proposed in this study. To evaluate the interface bonding property in the girder between the SSPP-ECC and concrete, a slant shear test and split tensile test were designed to study the interfacial shear and tensile properties of the ordinary concrete/ordinary concrete (OC/OC) and ordinary concrete/SSPP-ECC (OC/ECC), where the results showed that SSPP-ECC could significantly improve the interface shear stress and split tensile strength compared to ordinary concrete. Furthermore, the damage status of OC/ECC no longer involved fracturing along the interface; instead, each of the two substrates was partially destroyed, which revealed that OC/ECC had a high bonding effect. Moreover, a restrained shrinkage test was carried out to evaluate the shrinkage property of SSPP-ECC, where the result showed that the shrinkage strain of SSPP-ECC was slightly lower than concrete, where the average cracking time for SSPP-ECC was far longer than for ordinary concrete under the same ambient drying conditions; furthermore, the stress rate for SSPP-ECC revealed that it was a low-cracking-risk material. Meanwhile, the crack width of SSPP-ECC was only 0.1 mm after 35 d, which showed that SSPP-ECC had a more substantial crack width control capacity relative to concrete. The test results initially verified the feasibility and great potential of economic SSPP-ECC applied in a bridge pavement leveling overlay.

3D printable concrete with natural and recycled coarse aggregates: Rheological, mechanical and shrinkage behaviour

In the current study, we examine the effect of using natural and recycled coarse aggregates in designing 3D printable concrete. We assessed the rheological behaviourusing a dynamic shear rheometer, and it was observed that the addition of coarse aggregates significantly decreased the yield stress and marginally lowered the plastic viscosity. This was attributed to the increase in the paste and water film thickness with the addition of larger aggregates. Therefore, a reduction in the superplasticizer dosage is required to obtain coarse aggregate mixtures with similar yield stress and buildability to the control mixture. The mechanical properties were evaluated by using beam and cube samples cut out from printed wall elements. A marginal decrease in compression and flexural strength was observed for both the mixtures with natural and recycled coarse aggregates. The total and autogenous shrinkage assessment was performed using mould cast prismatic specimens, while the shrinkage cracking potential was evaluated using the restrained ring test. The coarse aggregate mixtures showed lower total and autogenous shrinkage. Notably, the addition of the saturated recycled aggregates significantly lowered the autogenous shrinkage, possibly due to internal curing. As a result, a relatively lower strain rate factor and slower development of tensile stresses occurred in the restrained shrinkage test, increasing the cracking age for the coarse aggregate mixtures. The current study, therefore, shows good potential for using natural and recycled coarse aggregates in 3D printable concrete.

Effective Reduction of Cement Content in Pavement Concrete Mixtures Based on Theoretical and Experimental Particle Packing Methods

The effective reduction of cement content in pavement concrete without compromising its fresh, mechanical, and durability properties can lead to more economical and sustainable pavement engineering. Because a reduction in cement content in concrete can be achieved by improving the particle packing of aggregates, this study attempted to improve a practical mix design procedure based on both theoretical and experimental particle packing methods. In this study, optimum aggregate blends were first identified using the Modified Toufar Model, which indicated good correlation with the experimental packing results based on a combined void content test. The Modified Box Test was then used to evaluate the fresh concrete performance and to justify the effectiveness of cement reduction. The results indicated that cement content could be reduced by up to 56 kg/m3 from the reference mix with the optimum aggregate gradation. The results from hardened concrete tests, such as compressive strength, flexural strength, and resistivity, confirmed that concrete properties were not compromised by the reduced cement content. Freeze-thaw resistance was improved with up to an 11% increase in the relative dynamic modulus at 300 freeze-thaw cycles. The optimum mixes also demonstrated reduced shrinkages, with a 12%–20% reduced strain at 180 days of free shrinkage and a delayed cracking age based on the restrained shrinkage test. Based on the laboratory test results, an improved mixture design procedure aided by the particle packing degree and the minimum excess paste-to-aggregates volume ratio is presented.

The effect of polypropylene fibres and coconut coir on restrained shrinkage and compressive strength of concrete

This paper investigates the comparative effects of the use of polypropylene fibres and coconut coir on restrained shrinkage and compressive strengths of concrete. Polypropylene fibres and coconut coir were cut (20 and 40 mm lengths) using 0.05 and 0.1% volume fraction of cement and were added to the concrete mix to cast 27 concrete prisms each for the two restrained shrinkage tests (100 mm × 100 mm × 300 mm). 108 Samples of concrete cubes (100 × 100 × 100 mm) containing 0, 0.05 and 0.1% volume fractions of polypropylene and coconut coir (20 mm and 40 mm in length) were also cast for compressive strength test. Concrete substrates and 8 mm mesh reinforcements were separately used to provide restraints for the concretes prepared for shrinkage tests. The shrinkage tests were monitored for 18 h and compressive test were carried out after 7, 14, 21 and 28 days of moist curing of concrete cubes. The results showed that prisms with substrates containing 0.1% polypropylene fibres and coconut coir reduced shrinkage by 31% and 15%, respectively. For wire mesh-reinforced prisms, 0.1% polypropylene and coconut coir decreased shrinkage by 16% and 7%, respectively. The compressive strength results also showed that polypropylene exhibited better strength performance than coconut coir.

On the development of MK/BFS alkali-activated materials as repair mortars: Performance under free and restrained shrinkage tests

This paper assessed the variables affecting the shrinkage and cracking of blended metakaolin/blast furnace slag (MK/BFS) alkali-activated mortars (AAM) designed for concrete repair. Twenty-one initial MK/BFS formulations with fixed workability were subjected to compressive strength and static modulus of elasticity, after which five formulations were selected for further tests. They were evaluated as to free shrinkage and restrained shrinkage on a concrete substrate and restrained shrinkage with stress concentrating devices. Mortars were also analysed in a concrete substrate with 0.25% addition of polypropylene fibres. The formulation with the lowest crack density was further studied in other conditions (prevention of water evaporation, thermal curing, higher aggregate/binder ratio, the addition of 0.25 and 0.75% PP fibres). In general, the results show that MK/BFS AAM may present satisfactory mechanical performance (high compressive strength, modulus of elasticity and bond strength) and free shrinkage results. However, this may bring misleading conclusions. Severe cracking is observed when the movement is restricted, irrespective of the formulation. Lower BFS content (20%), higher aggregate/binder ratio, fibres and prevention of moist evaporation help the reduction but not suppress the cracks, which were observed in AAM and also in reference PC mortar.

Restrained Shrinkage Mechanism of Ultra High Performance Concrete

The understanding and controlling of the restrained shrinkage is critical for the application of ultra high performance concrete (UHPC). This study made an analysis of restrained shrinkage mechanism of four kinds of UHPCs based on the direct tensile test accompanied with acoustic emission (AE) source location, free shrinkage test and restrained shrinkage test. The effects of UHPC tensile properties (strain softening or strain hardening) and high performance calcium sulphoaluminate (HCSA, a new kind of expansion agent) dosages (0%, 3% and 6% by mass of total binder) were investigated. The restrained shrinkage cracking mechanism of strain hardening UHPC and strain softening UHPC was analyzed based on AE analysis method under direct tensile loading. The results indicates that strain hardening UHPC shows multiple micro-defects to relax the restrained tensile stress marginally while strain softening UHPC shows several hairline cracks to relax the restrained tensile stress evidently. In ASTM C1581-04 ring test, the restrained shrinkage of strain hardening UHPC with HCSA dosage of 0%, 3% and 6% at 80d is 141 με, 96 με and 16 με, respectively. The HCSA expansion agent can effectively reduce the restrained shrinkage of UHPC and the influence on the structure.

Use of by-products for partial replacement of 3D printed concrete constituents; rheology, strength and shrinkage performance

In this paper, fly ash, ladle furnace slag and limestone filler were utilized in concrete used as material for additive manufacturing (3D printing). Fly ash and ladle furnace slag were used as a replacement of cement (30% wt.) and limestone filler as a replacement of siliceous aggregates (50% wt.). Work­ability of fresh concretes that contained these by-products was measured 0, 15 and 30 minutes after mixing. Three different workability tests were conducted and compared: flow table, ICAR rheometer and an experimental method that measures the electric power consumption of the motor that rotates the screw extruder. Workability parameters that were measured were evaluated regarding printability of mixtures. Density, ultrasonic pulse velocity, compressive and flexural strength were measured on hardened concrete. Additionally, relative like­­li­hood of cracking of different concrete mixtures was estimated by per­forming restrained shrinkage test (ASTM C1581). Results showed that use of fly ash or ladle furnace slag as binder, and limestone filler as aggregate decreases slightly the mechanical properties of concrete but improve its durability re­garding cracking potential. Monitoring of electric power consumption of screw extruder motor was found to be an effective method for measuring easily real-time workability and define if a mixture is printable or not.

Early age shrinkage cracking of restrained metakaolin-slag-palm oil fuel ash binder geopolymer mortars

The purpose of this study is to investigate the effects of a ternary geopolymer binder (MKSP) on the early-age shrinkage cracking, creep relaxation, and stress development of a restrained mortar containing alkali activated metakaolin (MK), slag(S), and palm oil fuel ash (POFA). Various mortars were prepared containing different proportions of these binder materials. The ASTM restrained shrinkage test was then conducted to determine the age at cracking, and strengths, free shrinkage and creep were also determined. The results indicate that MKSP with 40% MK, 40% slag, and 20% POFA exhibits the lowest shrinkage strain, possesses sufficient compressive strength (52 MPa) with a creep relaxation (4.2 MPa), and delays the age of mortar cracking for 18 days. Therefore, the use of a ternary MKSP is demonstrated to reduce the early age cracking in mortars. This finding has significant benefits for structures that require a high resistance to cracking, such as pavements

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP), steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%.