Ultra-high Performance Concrete Mixes Research Articles

Utilizing sugar factory lime waste and crumb rubber for sustainable Ultra-High-Performance Concrete

Ultra-High-performance Concrete (UHPC) offers significant advancements in construction due to its superior strength and durability. However, its traditional formulation demands extensive cement use, leading to high costs and adverse environmental impacts. This research explores the feasibility of repurposing lime waste, a by-product of sugar production, as a substitute for cementitious materials in UHPC, while also examining the use of crumb rubber powder as a complementary filler within the UHPC matrix. Glass, steel, and synthetic macro fibers are also added to improve the ductility of the concrete mix. A series of mechanical tests are conducted to evaluate the performance of the developed concrete. The results are compared with those of conventional cement and other cement substitutes. It is found that replacing 10 % of cement with lime waste and rubber powder produces the optimal UHPC mix, with 104 MPa compressive strength, 7.1 MPa bending strength, 5.8 MPa tensile strength, and 32.8 GPa modulus of elasticity. Moreover, steel fibers are the best reinforcement option, as they significantly improve the ductility and malleability of the concrete, achieving 13,456 J rupture energy and 17.4 MPa bending strength. However, a microstructure analysis reveals that the cement substitutes cause a slight deterioration in the concrete quality, but this is compensated by the benefits of the fibers. It is also shown that the use of lime waste and rubber powder reduces the carbon footprint and the cost of UHPC, making it a more sustainable and economical choice for construction materials. Therefore, it is concluded that the use of lime waste and rubber powder as cement substitutes in UHPC is a feasible and beneficial strategy for developing environmentally friendly UHPC with enhanced mechanical properties. This study contributes to the advancement of eco-conscious UHPC and opens new avenues for future research.

Using Multiple Machine Learning Models to Predict the Strength of UHPC Mixes with Various FA Percentages

Ultra High-Performance Concrete (UHPC) has shown extraordinary performance in terms of strength and durability. However, having a cost-effective and sustainable UHPC mix design is a challenge in the construction sector. This study aims on building a predictable model that can help in determining the compressive strength of UHPC. The research focuses on applying multiple machine learning (ML) models and evaluating their performance in predicting the strength prediction of UHPC. Two reliable metrics are used to evaluate the performance of the model which are the coefficient of determination (R2) and mean squared error (MSE). The parameters that are affecting the compressive strength of UHPC are fly ash percentage levels (FA%), superplasticizer content, water to binder ratio (w/b), and curing period. A total of 54 ML models were used, consisting of Linear Regression, Support Vector Machines (SVM), Neural Networks, and Random forests algorithms. Among these models, Random Forest proved to be the most effective in capturing the relationships in UHPC’s behaviour with an R squared score of 0.8857. The Random Forest ML model is also used in this paper to conduct a parametric study that will help in obtaining the compressive strength of UHPC with higher content of FA%, which is not sufficiently studied in the literature.

Assessing the Environmental Sustainability of UHPC in Modern Construction Practices

A comprehensive examination was undertaken to investigate various aspects related to the development and application of Ultra-High-Performance Concrete (UHPC). The research explored eco-friendly approaches, such as incorporating supplementary cementitious materials and nanoparticles, optimizing binder systems, and assessing chemical activators. These modifications improved mechanical properties and reduced environmental impact, including embodied CO2 emissions. Additionally, the utilization of waste materials like CRT glass showed energy savings and reduced emissions. Studies focused on optimizing UHPC mix designs, emphasizing a balance between performance and environmental impact. Techniques like statistical mixture design methods and dynamic testing assessed UHPC's environmental and economic impacts, highlighting significant energy savings and reduced CO2 emissions with waste material recycling. Overall, the research contributes valuable insights into UHPC development and its ecological footprint in construction

PACKING ORDER THEORY FOR ULTRA-HIGH PERFORMANCE CONCRETE MIX DESIGN: A CRITICAL REVIEW

Ultra-high-performance concrete (UHPC), also known as reactive powder concrete (RPC), is a relatively new construction material with improved mechanical properties and long-term performance. UHPC is manufactured using a specific matrix of well-graded granular particles including Portland cement, supplementary cementitious materials (SCMs), and fine aggregates. The cementitious material matrix is hydrated using a relatively low water-to-powder ratio and high range water reducing chemicals (HRWR). The hydrated mix is augmented with high grade random steel fibers. UHPC superior mechanical performance and durability is attributed to the high packing order of the granular materials within the UHPC mix resulting in lower voids, reduced permeability, and high density. Accordingly, UHPC design depends on proportioning the mix granular material to produce minimal void content (i.e., produce highest packing order). This research paper discusses UHPC mix constituents, proprietary UHPC mix designs, sizes of granular particles, and resulting packing order. Moreover, a critical review of the particles packing order approach used in UHPC mix design is presented. Possible improvement of UHPC mix design may result in economic mixes, enhanced mechanical properties, and increased durability.

Effect of nano SiO2 on rheology, nucleation seeding, hydration mechanism, mechanical properties and microstructure amelioration of ultra-high-performance concrete

The use of Nano SiO2 products will likely change cement, concrete construction sector. Their stability, low toxicity, and ability to functionalise with chemicals and polymers have drawn interest. When mixed with hybrid nanomaterials, nanostructured silica with unique geometric properties can improve biomaterial conjugates. Few scientists have studied the effects of Nano SiO2 on cement-based composites microstructural characterisation and mechanical behaviour. In this study four combinations were made by adding 0%, 1%, 2%, and 3% Nano SiO2 by cement weight. The tested Ultra-High-Performance Concrete (UHPC) mixes with various mechanical and microstructural characterisation techniques utilised. The finding suggests that the UHPC mixture with 2% Nano SiO2 has better mechanical and microstructural capabilities than the others. The study found that UHPC samples with more Nano SiO2 had higher mechanical strength than the reference sample. The study found that adding UHPC 2% Nano SiO2 to the mix increased compressive, split tensile, and flexural strength by 56%, 37%, and 28%, respectively. In UPV testing, this UHPC NS-2% mix had the greatest average velocity 4883 m/s and 4951 m/s for 28 and 90 days, suggesting a stronger concrete matrix. In optimum UHPC mix due to nucleation effect of Nano SiO2 and hydration of cement generates to more Calcium Silicate hydrate gel formation and less ca/si ratio is 0.54. It will lead to produce the dense UHPC with lowest porosity. The environmental and economic benefits of UHPC with Nano SiO2 make it a suitable building material for various civil engineering applications.

Ultra-High Performance Concrete: Recycling and Issues

Ultra-high performance concrete (UHPC) is used in infrastructure due to the outstanding mechanical and durability properties. On the other hand, infrastructures reach an end of life and all materials must be restored, replaced or recycled. Two years old UHPC was conventionally crushed with some difficulties, due to the high steel fibres content and strength, to prepare aggregates (0-32 mm). Some aggregates still contained fibres. A concrete with compressive strength class C 30 / 37 was taken as a reference and a mixture with 50% addition of UHPC recycled aggregates was prepared. The blend with 50% UHPC aggregates exhibited a reduction of the strength at 28 days at 40 MPa as compared to the reference mixture with 68 MPa. The modulus of elasticity was reduced to 25’295 MPa. The reference mixture showed 36’709 MPa. The chloride migration was 10.3 x 10-12 m2/s for the UHPC recycled concrete and 8.2 x 10-12 m2/s for the reference. The water permeability of the recycled mixture with UHPC aggregates showed a higher value of 11.7 g/m2h as compared to 8.3 g/m2h of the reference. The values correlated with the higher saturable porosity 17.2% of the recycled UHPC mix. Thus, the recycling of UHPC needs a modified demolition and crushing procedures as for conventional concrete. The addition of UHPC aggregates in conventional concrete does not necessarily improve the performance. Adjustments in the aggregate preparation and mix design are required to allow the use of recycled UHPC aggregates within cementitious systems.

Incorporation of self-healing of UHPC in structural design approaches through healable crack width threshold and kinetics: The case study of H2020 project ReSHEALience database

Ultra-high-performance concrete (UHPC) stands out as a crucial construction material, boasting outstanding mechanical properties and exceptional durability in its uncracked state. The distinctive strain-hardening tensile behavior of UHPC necessitates a consideration of material and structural durability in the cracked state, prompting a rethinking of structural concepts and design approaches. Consequently, various competing mechanisms, including material deterioration, self-sealing, and self-healing capabilities, require meticulous assessment. The autogenous nature of the self-healing capacity of the material, crafted with compositions tailored to specific mechanical properties, further underscores this evaluation. This study elucidates above concepts by compiling and analyzing an extensive database of crack closure data obtained and processed through image processing techniques. This research specifically delves into appraising the self-sealing capacity of UHPC under structural service conditions, encompassing challenges such as chloride and sulfate attacks. Additionally, it endeavors to distinguish the crack healing kinetics of diverse UHPC mix designs, calibrating them across varying crack widths (0–20, 20–50, 50–100, 100–300 μm) and diverse healing environments. These findings assume significance in establishing the "healable width threshold" and the "self-healing coefficients of the crack healing kinetics law" under "structural service conditions".

Physio-chemical, mechanical and fracture analysis of ultra-high performance cementitious composite

The present research aims to develop cost-effective and environmentally friendly Ultra-High Performance Concrete (UHPC) composite using fly ash and quartz powder as a sustainable alternative to cement. The performance of various constituents is examined, and their influence on fresh and hardened properties is investigated for the optimum trial mix design. The results show that a cube compressive strength of 144 MPa was achieved with fly ash content of 20% and 10% quartz powder and other ingredients without any special heat treatment. Advanced characterization studies such as heat of hydration and X-ray diffraction analysis were performed to understand the performance of fly ash blended UHPC. Further, various fracture properties, such as fracture toughness, fracture energy, brittleness number, etc., were investigated considering geometrically similar notched beam specimens for UHPC mix with 1.5% and 2.5% steel fibre content. The optimum UHPC mix achieved good scores in terms of the strength index and the carbon emission index, indicating the concrete is eco-friendly and sustainable.

Eco-Innovative UHPC-Enhancing Sustainability, Workability, and Ductility with Recycled Glass Cullet Powder and Plastic Bottle Hybrid Fibers.

Utilizing waste materials in producing ultra-high-performance concrete (UHPC) represents a highly effective approach to creating environmentally sustainable concrete using renewable resources. This study focused on incorporating ground glass cullet (GP) at various replacement levels in UHPC production. Additionally, plastic bottle fibers (PBFs) were derived from discarded plastic bottles and employed in the mix. The replacement levels for GP spanned from 0% to 40%. Single-use plastic bottles were transformed into strip fibers, both with and without the inclusion of microsteel fibers, at varying contents of 1.1% and 2.2% (volume-based). A single-fiber test was conducted on PBFs under different strain rates. The introduction of optimal GP content had a profound positive iMPact on compressive strength. Incorporating 2.2% plastic strips induced strain hardening behavior, while further inclusion of microsteel fibers resulted in substantial enhancements in mechanical properties. Two types of microsteel fibers were employed, characterized by different aspect ratios of 65 and 100. The optimum GP content was identified as 10%. Moreover, the UHPC mix achieved superior compressive strength, exceeding 140 MPa when composed of 1.3% (volume-based) microsteel fibers with an aspect ratio of 65 and 2.2% PBF (volume-based). Notably, mixtures featuring microsteel fibers with a higher aspect ratio demonstrated the highest flexural strength, exceeding 8000 N in the presence of 2.2% PBF. Longer microsteel fibers exhibited adequate slip properties, facilitating strain transfer and achieving a strain-hardening response in conjunction with plastic bottle fibers. These findings illuminate the potential for harnessing hazardous waste materials to improve the performance and sustainability of UHPC formulations.

Mechanical Properties of Ultra-High Performance Concrete (UHPC) and Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) with Recycled Sand

Use of high-cost raw materials such as quartz sand can limit wider application of ultra-high performance concrete in concrete construction. In this experimental study, recycled sand was used to fabricate ultra-high performance concrete (UHPC) and ultra-high performance fiber-reinforced concrete (UHPFRC). Green UHPC with ordinary Portland cement and industrial by-products such as silica fume, fly ash, as well as recycled sand was first developed through two-step packing density tests to optimize the mix design. UHPFRC was then developed based on the UHPC mix designs and by using 1%, 2%, or 3% 13-mm straight steel fibers (SSF). The compressive strength, elastic modulus, and flexural tensile strength was 128 MPa, 46.9 GPa, and 11.9 MPa, respectively, after 28 days at water-to-binder ratio of 0.17 and with 2% SSFs. All high-performance concretes in this work utilized 100% commercially available recycled sand that was produced by wet processing method. Mechanical characteristics such as strength, elastic modulus, and density, absorption, and voids of the UHPC/UHPFRC were investigated. Development of autogenous shrinkage of UHPC/UHPFRC with recycled sand was monitored for 12 weeks, while mercury intrusion porosimetry test and scanning electron microscopy were performed for microstructural investigation. Finally, the environmental impacts and economical aspects of the green UHPC were evaluated by life cycle assessment (LCA) and cost analysis.

Effects of thermal properties on temperature field of UHPC structures under fire conditions

Ultra-high-performance concrete (UHPC) is increasingly used for bold structures worldwide due to its exceptional mechanical properties, but its fire performance is not well known. Standards and literature provide limited information and data on the thermal-physical properties of some UHPC mixes exposed to high temperatures. This study aims to partially fill this gap. The thermal parameters of UHPC were determined experimentally and then compared with another UHPC mix proposed in the literature and also with those defined in EN 1992–1.2 for normal strength concrete (NSC). To understand the thermal diffusivity (i.e., the thermal field) of UHPC and NSC structures, a FEM -based numerical application was performed using Abaqus software, assuming the thermal-physical data of UHPC and NSC. Cross sections with the experimentally determined UHPC properties showed quite similar behavior to NSC. However, using the UHPC data proposed in the literature, the thermal diffusion in the cross-section appeared to be much more severe. The thermal-physical properties of UHPC can vary greatly depending on the mix design, with UHPC cross-sections exhibiting a maximum 110% greater thermal field than those simulated with NSC properties.

Influence of graphene oxide in the hydration mechanism by reinforcing mechanical strength and microstructural Characterization of ultra-high-performance concrete (UHPC)

In the past few years, one of the most promising graphite-based nanomaterials in the construction industry has been Graphene Oxide (GO) due to its outstanding performance combined with cementitious composites. Introducing extensive Engineering Cementitious Materials (ECMs) improves Ultra-High-Performance Concrete (UHPC) mechanical, durability, and microstructural characteristics. Very few studies have been concentrated on cement pastes, mortars, and regular concrete, high strength concrete. Limited studies on UHPC with large volumes of ECMs done. The present investigation mainly focuses on improving the UHPC in fresh, mechanical, and microstructural behavior. Four mixes were prepared with GO (0.00%, 0.03%, 0.06%, and 0.1% by weight of cement) and a water-cement ratio of 0.20. Results indicated that the mix with 0.06% GO had a better outcome and improved the compressive, split tensile, and flexural strength compared with other test mixes. Microstructural analysis carries out using x-ray fluorescence (XRF), x-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-dispersive x-ray Spectroscopy (EDS), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), Fourier-Transform Raman Spectroscopy (FT-RAMAN) on 28 days UHPC mixes and quality of the concrete mixes analyzed with Ultrasonic Pulse Velocity (UVP) test. They developed and established the fundamental step toward the cost-effective, eco-friendly, sustainable UHPC.

Effect of high-volume substituted nanosilica on the hydration and mechanical properties of Ultra-High-Performance Concrete (UHPC)

The effect of substituting a large amount of silica fume (SF) with nanosilica (NS) on the hydration behavior and mechanical properties of Ultra-High-Performance Concrete (UHPC) was investigated. Derivative thermogravimetric analysis showed that NS had the highest reactivity among the ingredients used in the UHPC mix. As the NS substitution rate increased, the time corresponding to the maximum exothermic peak decreased, and the maximum exothermic peak increased. Nuclear magnetic resonance results verified that the longest mean (silicate) chain length of C-S-H, which is 16.8 that it is improved approximately 68 % than plain specimen, was obtained at 10 % NS replacement rate. In the matrix (i.e., UHPC), the highest compressive strength is 161.5 MPa which obtained 10 % NS replacement rate, and the compressive strength was gradually decreased when NS replacement rate was increased more than 20 %. The highest compressive strength and the best tensile performance of UHP-FRC, i.e., the tensile strength and strain energy density, were also obtained at 10 % NS replacement, and there were improved approximately 2.2 %, 9.3 %, and 42.7 % compared to the plain specimen, respectively. However, the highest pullout strength and lowest porosity were achieved with 20 % NS replacement due to the densified fiber-matrix interfacial transition zone. These results suggest that the optimal rate of substitution of SF with NS in UHPC is 10 %–20 %.

Strength prediction and stochastic analysis of ultra-high performance concrete columns under the explosive blast load

The performance research based on numerical and experimental studies on ultra-high performance concrete (UHPC) generally considers it as an isotropic material, which is obviously different from what it really is in practical engineering. A database of UHPC compressive strength was investigated, having the same UHPC mix proportion as the field blast experiment, to show how the strength of UHPC varies in compression. It is found that Weibull distribution is the best fit of its probability model. A combination of Monte-Carlo and Finite Element method is used, adopting the available UHPC compressive strength, to reproduce the field blast test on UHPC columns. Both the non-spatial and spatial variability of material properties of the UHPC columns are under consideration to conduct the UHPC column strength prediction under blast loads. The residual loading capacity, damage index and failure mode of UHPC columns with different sizes damaged by different explosion severities are obtained by non-spatial simulation and spatial simulation respectively. It can be concluded that compared with the non-spatial model, the numerical simulation results of the spatial model are closer to the experimental situation. Therefore, inclusion of spatial variability is recommended for reliability-based blast-resistant design for UHPC column.

Machine-Learning-Based Comprehensive Properties Prediction and Mixture Design Optimization of Ultra-High-Performance Concrete

Ultra-high-performance concrete (UHPC) is widely used in the field of large-span and ultra-high-rise buildings due to its advantages such as ultra-high strength and durability. However, the large amount of cementitious materials used results in the cost and carbon emission of UHPC being much higher than that of ordinary concrete, limiting the wide application of UHPC. Therefore, optimizing the design of the UHPC mix proportion to meet the basic properties of UHPC with low carbon and low cost at the same time will help to realize the wide application of UHPC in various application scenarios. In this study, the basic properties of UHPC, including the compressive strength, flexural strength, fluidity, and shrinkage properties, were predicted by machine-learning algorithms. It is found that the XGBoost algorithm outperforms others in predicting basic properties, with MAPE lower than 5% and R2 higher than 0.9 in four output properties. To evaluate the comprehensive performance of UHPC, a further analysis was conducted to calculate the cost- and carbon-emissions-per-unit volume for 50,000 UHPC random mixes. Combined with the analytical hierarchy process (AHP) model, the comprehensive performance of UHPC, including basic properties, cost-per-unit volume, and carbon-emissions-per-unit volume, was evaluated. This study proposes an optimized UHPC mix proportion, based on low-cost or low-carbon emission, oriented to comply with the excellent overall performance and obtain its corresponding various properties.

Multi-Criteria Risk Analysis of Ultra-High Performance Concrete Application in Structures

In developing countries, ultra-high-performance concrete (UHPC) has not garnered sufficient attention, and its potential industrial applications remain largely unexplored and underdeveloped. The purpose of this paper is to assess the risk associated with integrating UHPC technology into the construction industry, focusing on economic, technical, and environmental facets, as highlighted by global research endeavors in this domain. In this study, a risk model is validated by analyzing diverse UHPC mix proportions from various studies and assessing the associated risk indices concerning constituent materials. The findings demonstrate that incorporating UHPC as a more robust alternative to earlier generations is plausible when considering multiple perspectives within the concrete industry. The preeminence of compressive strength and the significance of service life as a pivotal cost factor during the maintenance period, coupled with comprehensive risk indices, underscore the excellence of UHPC. Comparing UHPC with high-performance concrete (HPC) and normal concrete (NC), it becomes evident that UHPC exerts a notably lower adverse impact on the ecosystem. Additionally, UHPC proves to be a more economically viable option, warranting the replacement of existing technologies.

Behavior and design of steel-UHPC composite beams subjected to negative moment

To improve the crack resistance of concrete deck slabs of steel–concrete composite beams in the negative moment regions, Normal Concrete (NC) and Ultra-high Performance Concrete (UHPC) were respectively used to cast the deck slab to investigate the effects of different slab materials on the failure modes, crack characteristics and flexural performance. The flexural performance tests under negative bending moment were conducted, and the impact of different slab materials on the mechanical performance of the composite beams were analyzed using the numerical simulation method verified by the tests. The method of calculating the ultimate flexural capacity of steel-UHPC composite beam, which considered the material micromechanics mechanism such as fiber distribution, orientation, burial depth and interfacial bond strength, was proposed based on the simplified plasticity theory and were verified with existing method by the test results of related literature. The results show that the force characteristics of the two composite beams were similar, and the failure modes were both flexural failures. Compared with the steel–concrete composite beam, the cracks of the steel-UHPC composite beam were more evenly distributed and narrower, with larger crack distribution spacing and fewer secondary cracks. The cracking resistance of composite beam can be effectively improved by using UHPC slab, and the flexural capacity improved slightly. The cracking load of the deck slab of the steel-UHPC composite beam was improved by 500%, the corresponding load when the crack width reached 0.2 mm was improved by 37.5%, and the ductility and ultimate flexural capacity were improved by 30% and 5 %. In addition, the ultimate flexural capacity of steel-UHPC composite beam should consider the tensile contribution of UHPC, and the proposed calculation method is suitable for steel-UHPC composite beam with different UHPC mix ratios.

Effect of using sugarcane leaf ash and granite dust as partial replacements for cement on characteristics of ultra-high performance concrete

A significant quantity of cement is necessary for the production of ultra-high-performance concrete (UHPC). However, some environmental issues are associated with cement production. The worldwide agricultural growth increases ash from agricultural waste (AW). Furthermore, industrial waste (IW) generated throughout the stone-cutting and processing has increased due to the growing demand for granite stone in construction. This research conducted a unique study that involved comparing the use of sugarcane leaf ash (SLA) as AW and granite dust (GD) as IW as partial substitutes for cement in the production of eco-friendly UHPC. The effect of employing SLA and GD with replacement ratios ranging from 20% to 50% on the mechanical and transport properties of UHPC was studied. In addition, this research investigated the effectiveness of partial replacement of natural fine aggregate (NFA) by recycled fine aggregate (RFA) with ratios ranging from 25% to 100% on the UHPC qualities. Moreover, the effect of elevated temperatures on the UHPC and the microstructural examination were investigated. Results demonstrated that the optimum replacement ratio of SLA or GD from cement was 20%, showing the best mechanical characteristics of the UHPC. For example, after 28 days of casting, the compressive strength increased by 12.16% and 8.44% when SLA and GD were added to the UHPC mix, respectively. Additionally, the 25% replacement ratio of RFA from NFA presented the best mechanical and transport properties of the UHPC. The mixes containing SLA positively affected the UHPC higher than those containing GD.

Properties of local ultra-high-performance concrete with low dosage of polyvinyl alcohol and steel fibre

Ultra-high-performance concrete (UHPC) delivers better durability and mechanical properties than normal-strength concrete. However, conventional UHPC requires heat treatment and a high dosage of high tensile steel fibre to achieve a compressive strength of 120 MPa. The present study was conducted to test a local UHPC with low fibre dosage and without heat treatment by incorporating different polyvinyl alcohol (PVA) fibre and steel fibre. The fibres included in the experimental works were 30 mm PVA macro fibre, 8 mm PVA fibrin and hooked end steel fibre with 35 mm in length. Four series of UHPC were studied, which consist of plain UHPC mix and three fibre-reinforced UHPC mixes. 1% fibre volume was incorporated into all the fibre-reinforced mixes. The mixes were tested for compressive strength, modulus of rupture, drying shrinkage and porosity The UHPC had a compressive strength of more than 120 MPa and modulus of rupture from 8 to 11 MPa. The drying shrinkage of all the UHPCs was less than 255με when cured at 100% relative humidity. The porosity recorded for the UHPC was 2%. Current findings indicated that steel fibre reinforced UHPC performed better than UHPC with PVA fibre in terms of mechanical properties However, UHPC with PVA fibrin performed better in terms of the drying shrinkage. In conclusion, UHPC with more than 120 MPa can be achieved with normal synthetic and steel fibre without special treatment.

A methodology to assess the evolution of mechanical performance of UHPC as affected by autogenous healing under sustained loadings and aggressive exposure conditions

This study investigates the evolution of the performance of an Ultra-High Performance Concrete (UHPC) under simultaneous action of sustained loading and aggressive environmental exposure. UHPC mixes were investigated containing different functionalizing micro- and nano-scale components to promote autogenous self-healing. In order to assess the healing capabilities in the different multi-action scenarios and the evolution of the mechanical response of the material over time, a tailored methodology was implemented, including non-destructive and destructive tests performed all along the scheduled exposure/healing times up to 12 months. In particular, an innovative set-up was designed to reproduce on the specimens the sustained flexural loading conditions a structure undergoes during its service life; the load was applied simultaneously with each of the three selected different exposures, to simulate the chloride and sulphate aggressive environments, besides a reference one. Multiple indices were defined to quantify the self-healing efficiency, which were further calibrated against experimental microscope crack observation as well as cross correlated with each other, as a further proof of the reliability of the proposed methodology. The results confirmed the material durability, especially in the cracked state, through its capacity of sealing the cracks and restoring original properties in short periods and preserving its load bearing capacity, thus providing solid argument for UHPC as the ideal candidate material for highly durable and sustainable structural applications in aggressive scenarios.