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Enhancing concrete’s resilience against freeze–thaw (F-T) cycles is a critical challenge in civil engineering, especially in cold climates, where repeated freezing and thawing lead to structural degradation. This review explores the effectiveness of various additives, including supplementary cementitious materials (SCMs) and chemical admixtures, in improving concrete durability under F-T conditions. Factors influencing F-T resistance include the type and percentage of SCM replacement, the water–cement ratio, pore structure refinement, and air entrainment. The mechanisms by which additives enhance the durability—such as reducing the permeability, improving the microstructure, and increasing the compressive strength—are examined through an extensive review of experimental studies. The findings indicate that manufactured additives, such as silica fume, metakaolin, nano-SiO2, and graphene oxide, significantly enhance the F-T durability by densifying the concrete matrix and mitigating internal damage. In contrast, natural additives, including rice husk ash and zeolite, show potential but require optimization to match the performance of industrial SCMs. Additionally, the preparation and treatment methods of these materials play a crucial role in their effectiveness. This review provides insights into optimizing concrete formulations to enhance the longevity and sustainability, offering practical recommendations for the use of SCMs in cold climates.

This study conducted an extensive literature review on rice husk ash (RHA), with a focus on its particle properties and their effects on the fresh, mechanical, and durability properties of concrete when used as a partial cement replacement. The pozzolanic property of RHA is determined by its amorphous silica content, specific surface area, and particle fineness, which can be improved by using controlled combustion and grinding for use in concrete. RHA particle microstructures are typically irregular in shape, with porous structures on the surface, non-uniform in dispersion, and discrete throughout. Because RHA has a finer particle size than cement, the RHA blended cement concrete performs well in terms of fresh properties (workability, consistency, and setting time). Due to the involvement of amorphous silica reactions, the mechanical properties (compressive, tensile, and flexural strength) of RHA-containing concrete increase with increasing RHA content up to a certain optimum level. Furthermore, the use of RHA improved the durability properties of concrete (water absorption, chloride resistance, corrosion resistance, and sulphate resistance). RHA has the potential to replace cement by up to 10% to 20% without compromising the concrete performance due to its high pozzolanic properties. The use of RHA as a partial cement replacement in concrete can thus provide additional environmental benefits, such as resource conservation and agricultural waste management, while also contributing to a circular economy in the construction industry.

The topic of sustainability of reinforced concrete structures is strictly related with their durability in aggressive environments. In particular, at equal environmental impact, the higher the durability of construction materials, the higher the sustainability. The present review deals with the possible strategies aimed at producing sustainable and durable reinforced concrete structures in different environments. It focuses on the design methodologies as well as the use of unconventional corrosion-resistant reinforcements, alternative binders to Portland cement, and innovative or traditional solutions for reinforced concrete protection and prevention against rebars corrosion such as corrosion inhibitors, coatings, self-healing techniques, and waterproofing aggregates. Analysis of the scientific literature highlights that there is no preferential way for the production of “green” concrete but that the sustainability of the building materials can only be achieved by implementing simultaneous multiple strategies aimed at reducing environmental impact and improving both durability and performances.

Cracks in concrete structures present a threat to their durability. Therefore, numerous research studies have been devoted to reducing concrete cracking. In recent years, a new approach has been proposed for controlling temperature related cracking—utilization of phase change materials (PCMs) in concrete. Through their ability to capture heat, PCMs can offset temperature changes and reduce gradients in concrete structures. Nevertheless, they can also influence concrete properties. This paper presents a comprehensive overview of the literature devoted to using PCMs to control temperature related cracking in concrete. First, types of PCMs and ways of incorporation in concrete are discussed. Then, possible uses of PCMs in concrete technology are discussed. Further, the influences of PCMs on concrete properties (fresh, hardened, durability) are discussed in detail. This is followed by a discussion of modelling techniques for PCM-concrete composites and their performance. Finally, a summary and the possible research directions for future work are given. This overview aims to assure the researchers and asset owners of the potential of this maturing technology and bring it one step closer to practical application.

The use of recycled fine aggregate in the production of concrete mixes is one of the elements of a circular economy. However, it is important to ensure that such a modification does not significantly affect the durability of the produced concrete elements. One possible criterion to check whether this condition is met is the practical application of the concept of equivalent concrete properties. The presented studies analyzed the properties of concrete with multi-component cement CEM V/A (S-V) and with recycled fine aggregate. The conducted analyses of the research results showed that with a 15% replacement level of natural sand with recycled sand, it is possible to maintain durability characteristics compared to concrete using only natural sand.

The macroscopic mechanical properties and frost resistance durability of concrete are closely related to the changes in the internal pore structure. In this study, the two-dimensional and three-dimensional ICT (Industrial Computerized Tomography) pore characteristics of C30 concrete specimens before and after freezing and thawing in clean water, 5 wt.% NaCl, 5 wt.% CaCl2, and 5 wt.% CH3COOK solution environments are obtained through concrete frost resistance durability test and ICT scanning technology. The effects of pore structure changes on concrete frost resistance, durability, and compressive strength mechanical properties after freezing and thawing cycles in different salt solution environments are analyzed. This paper provides new means and ideas for the study of concrete pores. The results show that with the increase in the freezing and thawing times, the concrete porosity, two-dimensional pore area, three-dimensional pore volume, and pore number generally increase in any solution environment, resulting in the loss of concrete compressive strength, mortar spalling, and the decrease in the relative dynamic elastic modulus. Among them, the CH3COOK solution has the least influence on the concrete pore changes; the NaCl solution has the greatest influence on the change in the concrete internal porosity. The damage of CaCl2 solution to concrete is second only to the NaCl solution, followed by clean water. The increase in the concrete internal porosity from high to low is NaCl, CaCl2, clean water, and CH3COOK. The change in the pore volume of 0.1 to 1 mm3 after the freeze–thaw cycle is the main factor for reducing concrete strength. The test results have certain guiding value for the selection of deicing salt in engineering.

This paper discussed the effects of modified metakaolin (MK) with nano-silica (NS) on the mechanical properties and durability of concrete. In the first phase, trial mixes of concrete were prepared for achieving the desired value of the 28 days compressive strength, and the charge passed in rapid chloride permeability test (RCPT). In the second phase, statistical analysis was performed on the experimental results using the response surface method (RSM). The RSM was applied for optimizing the mix proportions for the required performance by exploiting the relationship between the mix characteristics and the corresponding test results. A blend of 10% MK + 1% NS as part of cement replacement exhibited the highest mechanical properties and durability characteristics of concrete; concrete mix showed that the 28-days compressive strength (CS) was 103 MPa, which was 15% greater than the CS of the control mix without MK or NS. The same mix showed more than 40% higher flexural and split-tensile strength than the control mix; also it resulted in a reduction of 73% in the rapid chloride permeability value. ANOVA technique was used for optimizing the nano-silica and metakaolin content for achieving maximum compressive strength and minimum RCPT value. Statistical analysis using ANOVA technique showed that the maximum compressive strength and lowest RCPT value could be achieved with a blend of 10% MK and 1.55% NS.

The causes of cracks in concrete are varied, and regardless of their origin, these cracks invariably have a detrimental impact on the durability of concrete structures and escalate their maintenance costs. This paper presents a comprehensive review of current knowledge regarding the methods of self-healing in concrete, ranging from autogenic and improved autogenic self-healing to the autonomous self-healing of concrete. Particular emphasis is placed on the methods of autonomous concrete self-healing: the bacterial healing method, the crystalline hydrophilic additives healing method, and the capsule-based self-healing method. The hypothesis is that applying these self-healing methods could potentially prevent damages or cracks in concrete caused by freeze–thaw cycles, thereby extending the lifespan of concrete structures. The mechanism of action and current achievements in the field are provided for each method.

Objective: This paper investigates the impact of carbonation and sulfuric acid attack on concrete pipes with chitosan addition.   Theoretical Framework: The carbonation and sulfuric acid attack of concrete structures results in a decrease in the durability and service life of structures such as sewage concrete pipes and oil wells and represents a substantial environmental and social concern. ...

PurposeThis paper aims to compare the environmental and social impacts of three types of rafts for mussel farming in Spain. These structures, traditionally made of wood, have a short lifespan and, because of their service conditions, require frequent maintenance in order to be fully operational. An innovative solution made with ultra-high performance concrete (UHPC) was developed in 2016 by RDC, being at the base of the pilots of the EU-funded project ReSHEALience (H2020-GA760824).MethodsIn order to quantify the environmental and social impacts generated by alternative solutions for the aquaculture raft, a life cycle approach has been used. The life cycle assessment methodology, according to ISO 14040 and ISO 14044 standards, has been used for the evaluation of the environmental impacts, while the social life cycle assessment (SLCA) methodology, according to the Guidelines for SLCA of Products and the social impact assessment method developed by Ciroth and Franze (2011), has been used for the evaluation of the social impacts: the same functional unit and the same stages of the life cycle to be included in the study has been set for the alternative solutions.Results and discussionBased on the LCA results, derived from the system boundary described in the “Goal and scope” section for the mussel aquaculture structures, the highest environmental impacts in the cradle-to-grave analysis are generated by the Traditional Raft with maintenance based on the periodic application of paints; the lowest environmental impacts are generated by the Traditional Raft with maintenance based on the progressive replacement of the damaged logs, while the Innovative Raft has an intermediate behavior in terms of environmental impact generation. Based on the S-LCA results, it can be stated that both the solutions generate high impacts; nevertheless, the Innovative solution has a slight lower impact than the Traditional solutions, which could be lowered if some precautions in the society policy are taken. Social hot-spots are identified in order to help reducing the overall social impacts.ConclusionsIn conclusion, it can be stated that, from both the environmental and social points of view, the Traditional Solutions for the aquaculture raft are the most “impactful,” especially when the maintenance is based on paint application. The use of innovative concretes allows to build longer lifespan rafts with minimum (or no) need of maintenance. Moreover, the behavior of new companies is more attentive to social aspects related to their activities and has a margin of improvement, when compared to traditional companies.