Durability Performance Research Articles

Leaching-Free durable antibacterial composite films constructed via delicate balance between potent contact sterilization and low adhesion

Durable antibacterial surfaces are often required high bactericidal ability and low bacterial adhesion property, but the potent bactericidal surfaces, especially based on the contact bactericidal mechanism, are often paradoxically intended to attract bacteria to adhere. In this work, a delicate balance between the potent contact bactericidal action and low bacterial adhesion was successfully achieved in quaternized fluoropolymer/SiO2 composite films (QFP/SiO2 CFs) through judicious selection of a common fluorinated monomer, a common quaternary ammonium monomer, and a common inert inorganic nanoparticle, to acquire suitable surface energy and chain mobility to ensure low bacterial adhesion, as well as to allow appropriate surface-exposed quaternary ammonium units to synergistically enhance the contact bactericidal action with the specific fluorinated side chains. The QFP/SiO2 CFs were conveniently fabricated through miniemulsion polymerization and followed squeegeeing technique. The QFP/SiO2 CF with an optimized composition exhibited extremely low initial adhesion of bacteria, potent contact bactericidal action, superior long-term antibacterial performance, easy sonication-assistant regeneration for multiple usage, and low cytotoxicity with non-leachable attribute. This work may guide the design and efficient fabrication of leaching-free durable antibacterial surfaces for biological applications, as well as provide an effective strategy to balance contact bactericidal action and low bacteria adhesion for durable antibacterial performance.

Flexural behavior of pre-damaged RC beams strengthened with UHPFRC-CFRP grid layer

Ultra-high performance fiber reinforced concrete (UHPFRC) using recycled tyre fibers and carbon fiber-reinforced polymer (CFRP) grid were combined to strengthen the pre-damaged reinforced concrete (RC) beams caused by coupling action of sustained loads and marine environment. The flexural tests were conducted to investigate failure modes, characteristic loads, deflection features, and strain behavior of the strengthened RC beams with different configurations. The results showed that they exhibited the typical bending failure without interfacial debonding, and their cracking, yield, and ultimate loads increased by 64.7 %−152.9 %, 105.7 % to 192 %, and 65.4–131.2 % compared with that of the RC beam (B0). By increasing the thickness of the UHPFRC layer and adopting the Y-type UHPFRC (using recycled tyre fibers), the stiffness, ductility, and synergistic performance among the main materials would be further improved, while the increase of the CFRP grid layers would decrease the ductility. Furthermore, analytical models considering the coupling action of sustained loads and marine environment were developed to calculate the characteristic loads, manifesting reasonable accuracy. The proposed UHPFRC-CFRP grid strengthening method has excellent mechanical and durability performance, cost-effectiveness, and environmental benefits, which can serve as a valuable reference for the innovation and development of structural strengthening technology.

Effect of diameter on the stability of granulated Ca(OH)2 during thermochemical cycling in a fixed bed reactor

One solution to reduce CO2 emissions and advance climate protection in the heat sector is the utilization of thermochemical energy storages (TCES) based on the material Ca(OH)2 to store waste heat or surplus electricity. In contrast to powdered materials, the material in granular form has a lower tendency to be affected by agglomeration effects and provides higher energy density and thermal conductivity. This results in enhanced durability, stability, and efficiency of the storage, making the storage material Ca(OH)2 in granular form more suitable for TCES applications. This work investigates the performance of a chemically unmodified granular sample over 15 storage cycles in a test fixed bed reactor and evaluates whether its performance and durability are already sufficient for potential applications without further modification. In addition, different granule samples with different diameters were also cycled to determine whether the selection of certain diameter sizes can improve the stability of the granules. Furthermore, different methods were used in the pre- and post-analyses to assess the stability of the samples. The comparison of three tested granular samples with different diameters reveals that the sample with a diameter of 2–4 mm has the highest durability and reactor performance. Despite a decrease in mechanical strength, this configuration could be suitable for applications with a small number of storage cycles, such as seasonal storages.

Seismic Performance of Corroded ECC-GFRP Spiral-Confined Reinforced-Concrete Column.

Preventing corrosion in the steel reinforcement of concrete structures is crucial for maintaining structural integrity and load-bearing capacity as it directly impacts the safety and lifespan of concrete structures. By preventing rebar corrosion, the durability and seismic performance of the structures can be significantly enhanced. This study investigates the hysteresis behavior of both corroded and non-corroded engineered cementitious composite (ECC)-glass-fiber-reinforced polymer (GFRP) spiral-confined reinforced-concrete (RC) columns. Employing experimental methods and finite element analysis, this research explores key seismic parameters such as crack patterns, failure modes, hysteretic responses, load-bearing capacities, ductility, stiffness degradation, and energy dissipation. The results demonstrate that ECC-GFRP spiral-confined RC columns, compared to traditional RC columns, show reduced corrosion rates, smaller crack widths, and fewer corrosion products, indicating superior crack control and corrosion resistance. Hysteresis tests revealed that ECC-GFRP columns, at a 20% target corrosion rate, exhibit an enhanced load-bearing capacity, ductility, and energy dissipation, suggesting improved durability and seismic resilience. Parametric and sensitivity analyses confirm the finite element model's accuracy and highlight the significant influence of concrete compressive strength on load-bearing capacity. The findings suggest that ECC-GFRP spiral-confined RC columns offer promising applications in coastal and seismic-prone regions, enhancing corrosion resistance and mechanical properties, thus potentially reducing formwork costs and improving construction quality and efficiency.

A study on sustainable foam concrete with waste polyester and ceramic powder: Properties and durability

The textile and apparel sectors currently produce millions of tons of textile waste annually on a global scale. Textile waste fibers are a viable option for sustainability as they can be utilized to reinforce cement-based composites internally by improving ductility and reducing the development of cracks. The issue of ceramic waste accumulation can be effectively resolved by using ceramic waste as supplementary cementitious materials (SCM), for sustainable construction, which also lowers energy use and CO2 emissions during the cement manufacturing process. This study evaluated the fresh, physico-mechanical, durability, and thermal characteristics of foam concrete (FC) reinforced with waste polyester (WP) incorporating waste ceramic powder (CP) as a replacement of cement in the rates of 0, 10 and 20 %. Twelve mixtures with a 0.3 water/binder (w/b) ratio were fabricated using a sodium lauryl sulfate foaming agent. The WP used in this study have four percentages of 0, 0.2, 0.4 and 0.6 % by volume. Durability performance of the mixtures for dry shrinkage, sulfate attack, high temperatures, alkali silica reaction and freeze-thaw cycles was also carried out. Microstructure of the mixtures was analyzed by SEM. Cost investigation and environmental impact of FC mixtures were also investigated. The findings indicated that the mixture with 10 % CP and 0.6 % WP had the largest 28-day compressive strength of 8.78 MPa, representing a 47 % decrease over the reference mixture (without CP and WP). The same mixture also exhibited the lowest dry shrinkage after the reference mixture. The mixture containing 0%CP and 0.2WP had the lowest thermal conductivity with a reduction of 74.0 % as per the reference mixture. The 0.4 % WP and 0%CP incorporated mixture exhibited the best thermal and F-T performance.

Durability of SFCB reinforced low-alkalinity seawater sea sand concrete beams in marine environment

Seawater sea-sand concrete (SWSSC) provides an alternative to normal concrete, while Steel-FRP Composite Bars (SFCB) offer corrosion resistance in offshore and marine structures. Despite their benefits, the long-term performance of SFCB-reinforced SWSSC structures remains under-explored. This study evaluated the durability of such beams, particularly focusing on the effects of using Portland cement versus low-alkalinity calcium sulphoaluminate (CSA) cement. The investigation involved tensile and pull-out tests conducted on SFCB, and flexural tests conducted on the beam components after accelerated marine environmental exposure over periods ranging from one to six months. Results highlighted that SFCB embedded in low-alkalinity CSA cement exhibited improved retention of tensile strength, elastic modulus, and bonding strength by 32.0 %, 39.1 %, and 56.7 % respectively, compared to that embedded in normal Portland cement concrete. Microstructural analyses showed much less hydrolysis of the resin matrix and shallower corrosion of the basalt FRP (BFRP) cover on the SFCB. Furthermore, flexural tests demonstrated superior cooperative performance between low-alkalinity CSA concrete with SFCB in beam components, showing only marginal degradation in crack density, crack strength, and yielding points. The ultimate failure load of beams made with CSA concrete was 1.89 times higher than those made with normal SWSSC after 6 months of exposure. These results underscore the potential of low-alkalinity concrete in improving the long-term durability and structural performance of SFCB-reinforced marine concrete infrastructures.

Flexible, transparent, and durable slippery liquid‐infused porous surface achieved by void‐centered PVDF‐co‐HFP membrane for self‐cleaning antifog coating

AbstractBioinspired smart surfaces, such as slippery liquid‐infused porous surfaces (SLIPS), have garnered significant attention due to their efficacy in self‐cleaning, antifouling, and antibacterial applications. Despite their advantages, SLIPS exhibit limitations such as compromised transparency, insufficient stability, and limited slippery performance, which have hindered their widespread practical use. To address these challenges, this article proposes a rational design utilizing a void‐centered poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF) membrane for slippery liquid‐infused porous surfaces with exceptional flexibility, transparency, durability, and superior slippery performance. These advancements promise to enhance high‐performance, self‐cleaning, and antifogging coatings. The membranes, featuring large‐area, thickness‐customizable void‐centered PVDF, are fabricated through a two‐step process involving phase separation and selective etching. The utilization of PVDF polymer, which has a refractive index similar to that of silicon‐based lubricant oil, enhances transparency, while macrovoids positioned at the membrane's center, acting as oil reservoirs, improve the stability and performance of the SLIPS surfaces. Experimental findings demonstrate remarkable transparency of up to 93% in the visible light range and a lubricant oil uptake of 2.32 at a porosity of 70%. Moreover, the developed SLIPS exhibit outstanding durability, maintaining slippery performance with sliding angles of <10° following exposure to either 400 consecutive droplets or aging for up to 40 days. This study significantly contributes to the development of future SLIPS, particularly for applications such as antifogging coatings on vehicle glass and solar panels, and self‐cleaning surfaces.

Performance of cementitious systems containing calcined clay in a chloride-rich environment: a review by TC-282 CCL

In this review by TC- 282 CCL, a comprehensive examination of various facets of chloride ingress in calcined clay-based concrete in aggressive chloride-rich environments is presented due to its significance in making reinforced concrete structures susceptible to chloride-induced corrosion damages. The review presents a summary of available literature focusing on materials characteristics influencing the chloride resistance of calcined clay-based concrete, such as different clay purity, kaolinite content and other clay minerals, underscoring the significance of pore refinement, pore solution composition, and chloride binding mechanisms. Further, the studies dealing with the performance at the concrete scale, with a particular emphasis on transport properties, curing methods, and mix design, are highlighted. Benchmarking calcined clay mixes with fly ash or slag-based concrete mixes that are widely used in aggressive chloride conditions instead of OPC is recommended. Such comparison could extend the usage of calcined clay as a performance-enhancing mineral admixture in the form of calcined clay or LC2 (limestone-calcined clay). The chloride diffusion coefficient in calcined clay concrete is reported to be significantly lower (about 5–10 times in most literature available so far) compared to OPC, and even lower compared to fly ash and slag-based concrete at early curing ages reported across recent literature made with different types of cements and concrete mixes. Limited studies dealing with reinforcement corrosion point out that calcined clay delays corrosion initiation and reduces corrosion rates despite the reduction in critical chloride threshold. Most of these results on corrosion performance are mainly from laboratory studies and warrant field evaluation in future. Finally, two case studies demonstrating the application of calcined clay-based concrete in real-world marine exposure conditions are discussed to showcase the promising potential of employing low-purity calcined clay-based concrete for reducing carbon footprint and improving durability performance in chloride exposure.

Behavior of the use of fine recycled concrete aggregates on rheological parameters and hardened mortar properties

The depletion of natural sand and the large amount of demolition waste that exists across the world are realizing the potential benefits of using this abundant waste to create recycled fine aggregates for use in the production of masonry mortars. This research aims to analyze the mechanical performance of mortar with recycled aggregates from old concrete, natural sand (NS) is partially substituted with fine recycled concrete aggregates (FRCA) and a quantity of superplasticizer has been added to keep the same spreading. The experimental study focused on different substitution rates by volume (0%, 25%, 50%, 75% and 100%) for recycled sand. Tests in the fresh state of the mortar such as spreading, yield stress and plastic viscosity will be carried out. In order to evaluate the mechanical performance of the recycled mortar, tests of compressive strength and flexural strength will be carried out. As well as the effect of the use of these aggregates on durability such as shrinkage and sorptivity. The results found show that recycled sand can be an alternative to natural sand, despite its detrimental effects on the durability properties of the mortar. These effects can be neglected given its contribution to the economic and environmental aspect. Adequate relationships have been established to predict rheological parameters, mechanical strengths and durability performances as a function of test parameters with high correlation coefficient and low root mean square error.

3D‐Printed Hydrogel Filter for Biocatalytic CO2 Capture

AbstractInnovative scalable CO2 capture technologies are urgently needed to combat the climate crisis. Reactive absorption in alkaline liquids, an essential process for capturing CO2 at atmospheric pressure, requires high gas–liquid contact and fast reaction kinetics. To meet these needs, self‐supporting hydrogel CO2 gas–liquid contactors (or simply “CO2 filters”) containing the CO2 selective catalyst carbonic anhydrase (CA) are developed using the direct ink writing additive manufacturing approach. The multifunctional filters are composed of semi‐interpenetrating polymer network hydrogels (IPNHs) of poly (ethylene glycol) diacrylate/poly (ethylene oxide) (PEG‐DA/PEO) upon photocuring during 3D printing. Formulations with PEG‐DA levels of 30–60 wt% are sufficiently homogeneous and reactive to produce coherent grids. Based on operational parameters, a 56 wt% PEG‐DA formulation is selected to continuously print self‐supporting 3D stacked cylindrical grids, with or without enzymes in ink. The resulting enzyme‐laden IPHN filters deliver ≈3 times higher CO2 capture efficiency than the no‐enzyme control filters in a laboratory‐scale absorption column test. However, the enhancement effect decreases significantly within 2 d of operation, likely due to burst release of enzymes caused by the flowing solution. Covalent crosslinking of CA near the surface, which can improve durability and CO2 capture performance, will be evaluated in future studies.

Ceramic waste powder as a cement replacement in concrete paving blocks: mechanical properties and environmental assessment

ABSTRACT In the quest for eco-friendly alternatives to ordinary Portland cement, a material extensively used in the manufacture of concrete paving blocks, this study explores the potential of ceramic waste powder. Towards this, a parametric investigation is conducted into the effects of substituting cement with ceramic waste powder on the mechanical properties and durability performance of mass-produced pressed concrete blocks. The findings reveal that the incorporation of ceramic waste powder as a partial cement replacement can markedly enhance the strength and durability of the paving blocks. Specifically, mixtures, containing 20% and 30% ceramic waste powder, demonstrated an increase in compressive and tensile strength by 30% and 19%, respectively, compared to their control counterparts. In addition, the modified blocks exhibited a decrease in water absorption and weight loss after undergoing freezing and thawing cycles by 8% and 40%, respectively. A life cycle assessment corroborates the environmental viability of ceramic waste powder as a cement substitute, indicating reductions across all environmental impact categories, with notable improvements. This research paves the way for more sustainable solutions in pedestrian pavement construction, underscoring the potential of ceramic waste powder as a significant contributor to global sustainability efforts in the construction industry.

Designing self-cleaning & flexible multifunctional wearable heater

Wearable fabric heater has aroused wide concern in personalized temperature regulation. However, it is still challenging to develop multifunctional wearable heater with multimodal & fast thermal response, good flexibility, strong abrasion, excellent washability, good antibacterial performance, and recyclability. To accomplish these properties, a self-cleaning & flexible multifunctional wearable heater is designed by spraying mixture of Ti3C2Tx MXene/ZnO composite and PDMS on cotton fabric (CF-MZP). The designed CF-MZP fabric heater shows high photothermal/electrothermal/synergistic conversion properties and fast thermal response (just 30 s). Furthermore, the CF-MZP fabric possesses excellent superhydrophobic and self-cleaning properties that endow the heater with strong abrasion, excellent washability, and good antibacterial performance. Interestingly, the CF-MZP heater also exhibits good breathability, durability and flexible performance, which is demonstrated as a flexible wearable heater attached to knuckle position of a human body, showing steady temperature of around 50.9 °C at a voltage of 3 V or about 80.5 °C upon NIR lamp (0.2 W cm-2) irradiation, either relaxed and bending (90° or 180°) states. Furthermore, the CF-MZP heater can be recycled by separating ordinary oil-water mixture and high viscous heavy oil. Consequently, the designed CF-MZP fabrics provide a good perspective application in self-cleaning, recycled, and flexible wearable heaters.

Durable Superhydrophobic Aluminum Surfaces against Immersion and Hot Steam Impact: A Comparative Evaluation of Different Hydrophobization Methods and Coatings

Controlling the wettability properties of metallic materials and surfaces can enhance their applicability and improve their performance and durability in several fields, such as corrosion protection, heat transfer applications, self-cleaning, and friction reduction. Here, we present and compare some versatile fabrication methods that can provide aluminum surfaces with durable superhydrophobic performance which are suitable for heat transfer applications. To probe their stability in heat transfer applications, two evaluation protocols are designed, one which suggests immersion in hot water for several hours, and a second testing against the harsh conditions of hot steam impact. The superhydrophobic aluminum surfaces are fabricated by first creating micro or micro-nano roughness on an initially flat surface, followed by the minimization of its surface energy through two hydrophobization methods, one wet and one dry, thus creating a series of different coating materials. Surfaces are then evaluated by immersing them in hot water and exposing them to steam impact. It is demonstrated that despite the fact that all hydrophobization methods tested resulted in surfaces exhibiting superhydrophobic properties, only the ultra-thin Teflon-like coating, obtained after plasma deposition using C4F8 plasma, exhibited robust superhydrophobicity with hysteresis lower than 8° when immersed in water at 90 °C for 10 h. This surface also showed minimal wettability changes and was the only one to retain its hysteresis below 6° after 4 h of exposure to hot steam.

Evaluating Use of Hydraulic Modified Sulfur Powder in Concrete Pavements: Laboratory Testing and Field Application

This study comprehensively evaluates the field applicability of hydraulic modified sulfur (HMS) as a concrete additive. We assessed the microstructural characteristics, mechanical properties, and durability performance of HMS at various replacement ratios in a laboratory setting. In addition, a field study was conducted by removing an existing conventional concrete pavement measuring (6000 × 12,000 × 70 mm, W × L × T) and overlaying it with HMS concrete. The experimental results revealed that HMS enhanced the mechanical and durability performance when used as a cement replacement at rates below 9%. These results satisfied the quality control standards and performance criteria specified in the Korean standard specification for cement-concrete pavements. The comparative analysis revealed that HMS concrete outperformed conventional concrete mixtures by 62.6% in sulfuric acid penetration depth, 14.8% in compressive strength retention after sulfuric acid immersion, and 53.1% in chloride-ion penetration resistance. Furthermore, no anomalies were detected during the 3-month follow-up period.

Health monitoring and maintenance of highway and bridge

In recent years, due to the rapid growth of traffic volume, the use frequency and load of Bridges have been significantly increased, and the service state of the bridge structure has deteriorated sharply. At present, there is no corresponding standard specification for the health monitoring and maintenance of Bridges in China, so the safety, durability and normal performance of Bridges are still the focus of people's attention. This paper summarizes the research results of health monitoring and maintenance at home and abroad, summarizes and analyzes the highway bridge health monitoring and maintenance, and introduces the bridge health monitoring system in China.

Wearable Solutions: Design, Durability, and Electrical Performance of Snap Connectors and Integrating Them into Textiles Using Interconnects

Wearable Solutions: Design, Durability, and Electrical Performance of Snap Connectors and Integrating Them into Textiles Using Interconnects

Nano-silica modified with silane and fluorinated chemicals to prepare a superhydrophobic coating for enhancing self-cleaning performance.

Superhydrophobic coatings with excellent self-cleaning performance have attracted significant concerns from researchers. Although various superhydrophobic coatings with prominent superhydrophobic properties have been fabricated, most developed coatings are still inadequate in pipeline scale inhibition applications. In this work, nano-silica (nano-SiO2) was modified by silane coupling of vinyltriethoxysilane (VETS) and 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFTS) to prepare a superhydrophobic coating. Organosilicon of PFTS and VETS was grafted onto the surface of SiO2 for preparing the superhydrophobic coating with low surface energy, and the superhydrophobic coating was cured via poly(vinylidene fluoride) (PVDF). The results showed that the contact angle of the prepared silica-based superhydrophobic coating, denoted as VETS-PFTS@SiO2/PVDF, is 159.2°, exhibiting outstanding superhydrophobicity performance. Furthermore, the superhydrophobicity coating also showed satisfactory durability performance in 200 g load wear test after 50 cycles. Importantly, the superhydrophobic coating displayed promising mechanical durability, chemical stability performance, as well as maintained excellent superhydrophobic properties after being placed in water for 3 weeks, indicating the potential for long-term utilization. In the simulated scale inhibition test, it was found that the synthesized coating can also significantly decrease the deposition rate of CaCO3 and successfully enhance its scale inhibition performance.

Effect of rice husk ash and coconut coir fiber on cement mortar: Enhancing sustainability and efficiency in buildings

This research investigated energy efficiency, insulation properties together with strength properties and cost-effectiveness, focusing on developing a sustainable mortar. Cement: sand of 1: 2.25 (by weight) mortar with varying rice husk ash (RHA) and coconut coir (CC) fiber contents were prepared. Physical, microstructure, strength, durability, and thermal performances were experimentally examined. Life cycle assessment and cost analysis were numerically examined. Adding CC fiber reduced the longer final setting time found with the RHA-based mortar. With 20 % RHA and 0.5 % CC fiber, weight was reduced by 9.2 % (compared to the conventional mortar), promising a lightweight mortar. Flexural strength was increased by 8.6 % with 0.5 % CC fiber addition, this was further increased to 13.6 % with 10 % RHA in the mixture. 20 % RHA and 0.5 % CC fiber mortar exhibits a temperature difference of 8.7°C, whereas the conventional mortar exhibits a temperature difference of 2.5°C, indicating a reduced thermal conductivity of the RHA-CC fiber mortar. This mortar reduced the CO2 emission, energy consumption, and manufacturing cost by 17.7 %, 13.6 % and 7.0 %, respectively, indicating the sustainability. A cost-effective and energy-efficient lightweight mortar with enhanced thermal insulation and flexural strength was achieved by reinforcing the conventional mortar with 20 % RHA and 0.5 % CC fiber for the applications of dwellings.

Optimization of the different controller parameters via OBL approaches based artificial ecosystem optimization involving fitness distance balance guiding mechanism for efficient motor speed regulation of DC motor

This study proposes a new optimization approach, which is called as artificial ecosystem optimization algorithm with fitness-distance balance guiding mechanism by using opposite based learning methods (FDBAEO_OBLs) for the speed regulation of direct current (DC) motor. The performance of the proposed FDBAEO_OBL algorithm is tested in two different experimental studies. In the first experimental study, the proposed approach is tested in the CEC2020 benchmark test functions and the FDBAEO algorithm, which included the best OBL approach, is determined using non-parametric Wilcoxon and Friedman statistical analysis methods. Second, the parameters of proportional integral derivative (PID), tilt integral derivative (TID), proportional integral derivative with filter (PIDF), tilt integral derivative with filter (TIDF), fractional-order proportional integral derivative (FOPID), fractional-order proportional integral derivative with filter (FOPIDF), proportional integral derivative with fractional-order filter (PIDFF) and fractional-order proportional integral derivative with fractional-order filter (FOPIDFF) controller structures to be used in DC motor closed loop speed control are determined with FDBAEO_OBL, and the performances of the controllers are investigated. Integral absolute error (IAE), integral time absolute error (ITAE), integral time squared error (ITSE) and integral squared error (ISE) performance indices are used as the objective function of the operation process in which the control parameters are determined. According to the comparative step response results of the controller structures, the four best controller structures for DC motor speed regulation are determined. The performances of these controllers are examined under different simulation conditions and according to the results obtained, it is seen that the best controller structure is FOPIDFF. The FDBAEO_OBL algorithm, which is used in both benchmark test functions and DC motor speed regulation, shows an effective, durable and superior performance in finding the optimal solution values during the optimization.

Insights into alkali and acid-activated volcanic ash-based materials: A review

This review provides a comprehensive study of the fundamentals of the alkaline and acid activation of volcanic ashes (VA), for mainstreaming their use as a conventional feedstock for developing geopolymers and their applications. The low reactivity in an alkaline environment is driven by the low content of the amorphous phase and the low solubility of iron, calcium and magnesium at pH > 12. Nevertheless, techniques such as mechanochemical activation has significantly improved the reactivity and the properties of the resulting products. In the acid phosphate medium, the high solubility of iron, calcium and magnesium ensures good reactivity and a high reaction rate at room temperature. As a result, the engineering properties of acid-phosphate-activated volcanic ash are superior to those of alkali-activated volcanic ash. The resulting materials have great potential for use as binders in concrete design, for the stabilization of compressed earth bricks and for the rapid repair of deteriorated concrete structures. However, significant research is required to fully understand their durability performances, life cycle and techno-economic viability for large-scale utilisation. Further, the limited availability of phosphate resources makes acid activation not a viable route to activate volcanic ash for building purposes. The acid-activated volcanic ash has potential in waste management applications such as nuclear waste or heavy metal encapsulation. Finally, volcanic ash emerges as a promising raw material for developing sustainable building materials through alkali and acid activation. This holds as its exploitation is non-disruptive, and processing requires less energy compared to calcined clay or fly ash.