Chloride Permeability Research Articles

The Influence of Salt Erosion on the Mechanical Performances of Ultra-High-Performance Concrete with Secondary Aluminum Dross

Secondary aluminum dross containing a large amount of active substance can be used to prepare concrete. The mechanical strengths, the mass loss rate (MR) and the relative dynamic modulus of elasticity (RME) of ultra-high-performance concrete with secondary aluminum dross are researched. The NaCl freeze–thaw cycles (F-Cs) and dry–wet alternation (D-A) effects with NaCl and Na2SO4 are considered. The corresponding permeability of chloride ions and the carbonation depth (Dc) are obtained. The scanning electron microscope (SEM) photos are researched to reveal the variation of the mechanical mechanism. Results show that after specimens’ suffering from the action of 20 NaCl D-As, the MR of ultra-high-performance concrete is the highest. Specimens exposed to 200 NaCl F-Cs show the lowest MR and CMC. The RME of UHPC under salt actions increase in the order of 20 NaCl D-As < 20 Na2SO4 D-As < 200 NaCl F-Cs. After suffering 200 NaCl F-Cs, 20 Na2SO4 D-As and 20 NaCl D-As, the corresponding Dc values are 1.86 mm to 2.31 mm, 1.79 mm to 2.23 mm and 2.11 mm to 2.76 mm. The flexural strength decreases at the rates of 0.99%–25%, 3.92%–27.84% and 1.47%–21.59% respectively. The MR increases and the RME decreases as the cubic function changes with the amount of salt erosion. After the secondary aluminum dross is added, the CMC decreases at the rates of 0% to 11.53%, 0% to 33.17% and 0% to 8.41% during the process of the salt action. The SAD can reduce the Dc with the decreasing rates of 19.48%, 23.55% and 19.73%. The SAD can increase the compactness of ultra-high-performance concrete. Ultra-high-performance concrete suffering from 20 NaCl D-As shows the largest number and the highest width of cracks. However, when the specimens are exposed to 20 Na2SO4 D-As, the number of cracks is the lowest and the width is the narrowest.

Study on the Effect of Ultra-fine Limestone Powder on the Resistance of Cement-slag Powder System to Chloride Ion Permeability

The effect of different limestone powder fineness on the chloride ion migration coefficient of the cement paste was tested using the Rapid Chloride Migration (RCM) method. The changes in the phase composition and pore structure of the paste were studied using hydration kinetics analysis, XRD and pore structure analysis. The results showed that before the chloride ion erosion, the limestone powder mainly exhibited filling effect, microcrystalline nucleation effect, and chemical activity effect. It reacted with the hydration products of cement to form calcium aluminate carbonate, which improved the strength of the hardened paste. After chloride ion erosion, the diffraction peak of calcium aluminate carbonate weakened, and Friedel’s salt was formed. With the increase of the specific surface area of limestone powder, the chemical activity of the powder became more obvious, and the generation of Friedel’s salt increased, leading to stronger resistance to chloride ion penetration. Limestone powder can reduce the porosity of the hardened paste and optimize the pore structure. When the particle size of the powder increased from 800 to 5000 mesh, the total porosity of the hardened paste decreased from 20.7% to 14.7%, and the most probable pore size decreased from 450nm to 75nm. Limestone powder with a particle size larger than 1500 mesh can fully exert its activity and play a role in solidifying chloride ions, thus improving the resistance to chloride ion penetration of limestone powder cement-based materials.

Properties evaluation of concrete made with recycled coarse aggregate modified by graphene oxide

Previous application of graphene oxide (GO) in recycled aggregate concrete (RAC) is the direct replacement of cement or binder to achieve performance improvement. To develop a more efficient recycled aggregate (RA) modification technique and improve the properties of the corresponding RAC, this paper performed GO solution pre-spraying and pre-soaking treatment on RA. The modification efficiency of GO was evaluated by compressive strength, interfacial transition zone (ITZ) properties, and chloride ion permeability of RAC. The results show that the pre-spraying and pre-soaking methods improved the compressive strength of RAC at different ages by 20%–28.6 % and 8.3%–30.8 %, respectively. The GO-modified RAC also exhibited lower electric flux in the chloride ion permeability tests. However, no significant effect was observed on the elastic modulus of RAC. The modified RAC showed lower total porosity and harmful pore content. Meanwhile, the GO-modified ITZ between old and new mortar had denser hydration products. As a result, the elastic modulus and hardness of the ITZ increased by 27.8%–65.8 % and 9.8%–107 %, respectively, while the width of the ITZ decreased by 15.4%–30.8 %. The good filling and nucleation effect of GO were credited with the enhancement mechanism of RA by pre-spraying and pre-soaking methods.

Influence of Nanoparticles on the Mechanical and Durability Properties of Concrete: A Microstructural Analysis

This study investigates the effects on mechanical and durability properties of concrete by including nano-silica, nano- titanium dioxide, and nano-alumina. The concrete mixes included nanoparticles in a range of quantities, from 0.5% to 4% by cement weight. Several experimental tests were performed, including those for chloride permeability, workability, compressive strength, and flexural strength. Compressive strength increased to 40.5 MPa and chloride permeability decreased to 1000 Coulombs, indicating an improvement in durability, when the nano-silica content was found to be 3%. Nano-titanium dioxide and nano-alumina also shown a minor but noticeable improvement. A detailed SEM microstructural analysis demonstrates the formation of a dense and refined microstructure, lending credence to the claims of improved mechanical properties. Results show that adding nanoparticles to concrete, particularly nano-silica, increases its performance without reducing its strength or durability.

Study on Bonding Performance of Magnesium Phosphate Cement Mortar in Chloride Corrosion Environment

The effects of nano‐SiO2 and hydroxypropyl methyl cellulose (HPMC) on the physical and mechanical properties of magnesium phosphate cement (MPC)‐based mortar under salt corrosion environment were studied. The variation of strength under salt corrosion environment was compared and studied. The chloride ion permeability of modified MPC mortar was evaluated by electric flux method. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to observe the composition and morphology of the samples under salt corrosion environment. Results showed that appropriate amount of nano‐SiO2 can significantly improve the compressive strength, flexural strength, and chloride ion penetration resistance of MPC‐based mortar under 3% NaCl solution corrosion. There existed an optimal dosage. The incorporation of HPMC would significantly reduce the compressive and flexural strength and the resistance to chloride ion penetration of MPC‐based mortar. Appropriate amount of nano‐silica and HPMC could improve the bonding performance of modified MPC‐based mortar under salt corrosion environment.

Durability and FTIR Characteristics of Sustainable Bacterial Concrete with Mineral Admixtures

The objective of this study is to optimize the concentrations of bacillus megaterium (BM), alccofine (AF), and silica fume (SF) in self-healing concrete while controlling the content of manufactured sand (M-sand). This research addresses the pressing need for sustainable alternatives to traditional cement as excessive energy consumption and environmental impacts continue challenging the construction industry. A novel “binary and ternary blended cementitious system” was developed, featuring twelve distinct mix proportions. M-sand was fully utilized as an acceptable aggregate substitute, with bacterial concentrations of (10–50)·105 cells/ml incorporated to mitigate crack formation. Cement was partially replaced with AF, and the M-sand content was adjusted from 0 to 20 % in 5 % increments. This study also uniquely evaluates the durability properties of the various cementitious systems, including water absorption, concrete density, porosity, long-term strength retention, and rapid chloride permeability – at intervals of 7, 14, and 28 days post-curing. Fourier transform-infrared spectroscopy (FTIR) was employed to analyze calcite precipitation, providing insights into the biochemical mechanisms. The results indicate that while SF demonstrates superior effectiveness compared to AF, combining both enhances durability compared to alternative mixes. The findings reveal that bacterial concrete incorporating zeolites can significantly improve structural strength and be a sustainable building material. Notably, incorporating additional cementitious materials with mineral admixtures increased strength by up to 10 % through optimized bacterial concentrations. The successful precipitation of calcium carbonate confirmed the beneficial properties of the bacterial agents, which are safe and non-toxic to the environment. Overall, this study contributes valuable knowledge on reducing cement usage and carbon dioxide emissions, positioning BM, alongside AF and SF, as a promising approach for environmentally friendly concrete solutions.

The influence of recycled aggregate on the properties of geopolymeric recycled concrete: A comprehensive review

This paper offers a comprehensive review of geopolymeric recycled concrete (GRC) research, particularly focusing on mechanical properties, durability, microstructure, and the interfacial transition zone (ITZ). The study emphasizes the influence of recycled aggregate (RA) content on GRC performance. Findings indicate that higher RA content leads to a gradual reduction in GRC’s compressive, tensile, and flexural strengths, elastic modulus, and toughness. The elastic modulus is most affected, followed by compressive strength, while tensile strength experiences the least decline. Moreover, increased RA content is associated with elevated water absorption, decreased resistance to chloride ion permeability, sulfate corrosion, acid, frost, and carbonization in geopolymer concrete. The integration of RA creates more intricate ITZs in geopolymer concrete, resulting in reduced bonding strength and a looser, more porous microstructure. However, the use of geopolymers can mitigate these effects by enhancing bonding in ITZs. The paper also presents a statistical analysis of compressive strength test results from various studies and proposes a preliminary method for estimating the compressive strength of geopolymer concrete with different RA replacement rates.

Experimental Analysis on the Characteristics of Concrete by Incorporating Steel Slag as Partial Replacement of Sand

Abstract: Steel slag is a by-product obtained in the manufacture of pig iron in the blast furnace and is produced by the blend of constituents of iron ore with limestone flux. Presently in India, owing to restricted methods of use, massive amounts of iron and steel slag are deposited in the yards of every production facility, occupying significant agricultural land, and seriously polluting the entire ecosystem. Meanwhile, the application of ecological environment protection has limited the mining of gravel, leading to a shortage of natural aggregate. Numerous studies have sought to replace natural aggregate in concrete with steel slag aggregate due to its good engineering qualities. The current research work is to investigate the concrete’s characteristics for M40-grade concrete by substitution of sand with steel slag at 10%, 20% and 30% during various curing ages. Several experiments were conducted on the characteristics of the concrete, compressive strength, and durability properties (such as water absorption and rapid chloride permeability test) up to the age of 90 days

Effects of healing start time and duration on conventional and high-performance concretes incorporating SAP, crystalline admixture, and sepiolite: A comparative study

This research investigates the self-healing capability of conventional and high-performance concrete containing either a superabsorbent polymer (SAP), a crystalline admixture (CA), or water-encapsulated in sepiolite by quantifying the recovery of water tightness through the water permeability test and chloride permeability via cracks and matrix penetration on healed specimens. Specimens were pre-cracked to a crack width range of 50–450 µm at 28 days. Specimens were healed under water in four time combinations: healing starting at the concrete age of 28 days or 56 days and a healing duration of 28 or 56 days. Additionally, a healing condition of presaturation during 1 day of water immersion and storage in a humidity chamber for 27 days was studied. The results show that delayed healing reduced the self-healing efficiency, and extending the duration to 56 days enhanced healing, especially for narrow cracks (≈100 µm), and reduced chloride permeability. Specimens with SAP showed superior early-stage healing, but low delayed healing. Sepiolite enhanced healing for delayed cracks with variable effectiveness. CA improved healing for both early and delayed healing, exhibiting low chloride penetration in healed specimens.

Reducing Chloride Ion Permeation during Seawater Electrolysis Using Double-Polyamide Thin-Film Composite Membranes.

Low-cost polyamide thin-film composite membranes are being explored as alternatives to expensive cation exchange membranes for seawater electrolysis. However, transport of chloride from seawater to the anode chamber must be reduced to minimize the production of chlorine gas. A double-polyamide composite structure was created that reduced the level of chloride transport. Adding five polyamide layers on the back of a conventional polyamide composite membrane reduced the chloride ion transport by 53% and did not increase the applied voltage. Decreased chloride permeation was attributed to enhanced electrostatic and steric repulsion created by the new polyamide layers. Charge was balanced through increased sodium ion transport (52%) from the anolyte to the catholyte rather than through a change in the transport of protons and hydroxides. As a result, the Nernstian loss arising from the pH difference between the anolyte and catholyte remained relatively constant during electrolysis despite membrane modifications. This lack of a change in pH showed that transport of protons and hydroxides during electrolysis was independent of salt ion transport. Therefore, only sodium ion transport could compensate for the reduction of chloride flux to maintain the set current. Overall, these results prove the feasibility of using a double-polyamide structure to control chloride permeation during seawater electrolysis without sacrificing energy consumption.

Effect of load on bonding properties and salt freeze-thaw resistance of bridge expansion joint concrete

In the seasonal frozen regions, the bridge expansion joint concrete (BEJC) is susceptible to damage during its service life, not only from vehicular loads but also from chloride salt erosion and the effects of freeze-thaw cycles. This study investigates the basic physical and mechanical properties of BEJC under different curing conditions. A rapid chloride permeability test was conducted to comparatively analyze the concrete's chloride ion penetration resistance. The microscopic crack width on the concrete bond surface is evaluated to assess the concrete bond performance under different loading durations. Additionally, the study explores the coupled effect of wheel loads and single-sided salt freeze-thaw cycles (WL-SFT) on the freeze-thaw resistance of BEJC, delving into factors such as spalling mass, water absorption rate, and pore structure characteristics (including air content, specific surface area, spacing coefficient) and connectivity. The results indicate that for specimens subjected to loading at 1–14 days and 3–14 days, the average crack widths on the bond surface are 14.36 µm and 10.09 µm, respectively, representing 5.27 times and 3.70 times those of unloaded specimens. The bond strength also decreases by 34.8% and 14.2%, respectively, compared to unloaded specimens. The increase in crack width leads to a reduction in bond strength, highlighting the importance of bond strength as a consideration for the actual opening time of roads in engineering projects. Furthermore, due to its smaller and more stable pore structure, the study suggests that WL-SFT almost does not damage standard curing (SC) concrete; however, it slightly disrupts the pore structure of natural curing (NC) concrete. In comparison, WL-SFT leads to the generation of more microcracks in both the surface and deeper layers of low-temperature curing (LC) concrete, resulting in the destruction of its pore structure and connectivity.

Performance of recycled aggregate concrete using copper slag as fine aggregate

The present study experimentally investigates the mechanical and durability performance of recycled aggregate concrete (RAC) incorporating copper slag as fine aggregate. The coarse aggregate obtained from recycling of construction waste is used as natural coarse aggregate and copper slag, the industrial by-product is used as fine aggregate in the current research work. Recycled aggregate concrete formed by substituting 50 % recycled aggregate as natural coarse aggregate is considered as the control mix for this experimental work. A total of seven RAC mixtures are made with copper slag as a substitution of fine aggregate of varying proportions (0%–100 %) giving an increment of 20 %. Compressive strength, split tensile strength, and microstructural behaviour of RAC mixtures were carried out for up to 90 days of curing to assess the mechanical property of RAC mixes. To evaluate the effect of copper slag on long-term properties of RAC mix water absorption, rapid chloride permeability and resistant to sulphate attack test is carried out for up to 90 days. The findings revealed that the mechanical properties of RAC mixes are improved up to 40 % substitution of copper slag. When exposed to sulphate, RAC mixtures gained weight while losing compressive strength. Results of water absorption and RCPT test showed a remarkable improvement with the incorporation of copper slag up to 40 %; beyond that point, the results were comparable to RAC mix (control). The progression of calcium silicate hydrate gel formation within the RAC blend was verified through scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction analysis across a range of curing periods spanning from 7 to 90 days.

Investigation into compressive property, chloride ion permeability, and pore fractal characteristics of the cement mortar incorporated with zeolite powder

As a non-homogeneous porous material, the microstructure of cementitious composites critically affects the mechanical and durability properties. This paper aims to analyze the effect mechanism of cement replacement by zeolite powder on the microscopic pore structure characteristics, macroscopic mechanical behavior, and durability of mortar to reduce cement consumption and improve mortar performance. The compressive strength and chloride ion permeability of mortar incorporated with zeolite powder were experimentally determined, and the effects of zeolite powder content on the composition of cement hydration products and pore structure were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and mercury intrusion porosimetry (MIP). The pore structure characteristics were quantitatively analyzed by fractal theory. The results shows that incorporating zeolite powder in cement mortar fills the pores, promotes secondary hydrate formation, reduces the Ca/Si ratio, refines the pore size, and reduces the porosity of large pores. Thus, the internal pore structure of the matrix is significantly improved, reducing the pore fractal dimension and improving the compressive strength and chloride ion penetration resistance. 15% cement replacement zeolite powder has been found optimal in reducing the porosity and chloride ion permeability coefficient while enhancing the compressive strength. The pore structure fractal dimensions calculated by the Menger sponge fractal model can quantitatively describe the pore structure distribution characteristics, which can help ascertain the relationship between zeolite powder content, pore structure quantitative characteristics, and macroscopic mechanical behaviors.

Mechanical and durability performance of ternary blended calcined clay and pulverized granite mortar composites

ABSTRACT Partially replacing cement with pozzolans, apart from the enormous technical benefits, has been reported as an effective approach to reducing greenhouse gases emanating from cement production. Calcined clay and pulverised granite, in recent years, have been experimented individually for their use as filler or pozzolan in concrete to improve workability and compressive strength. This research includes study of the synergistic characteristics of these two mineral admixtures and their influence on the mechanical and durability properties of mortar. Cement was partially substituted with 5–20% by weight of the composite material to form a ternary blended cement composite. The compressive strengths of the ternary blended cements were evaluated at 3, 7, 28 and 90 days. Durability properties such as alkali silica reactivity (ASR), rapid chloride permeability test (RCPT) and performance of the blended cements in aggressive media have been discussed. Test results indicated that, blended cements containing 5% and 10% of the pozzolan recorded similar compressive strengths at 28 days and outperformed it by 2.4% and 0.6% respectively at 90 days. Beyond 10% replacement, compressive strengths declined. The ternary blended cements were found to be highly reactive, potentially causing ASR in concrete than the reference cement.

Effect of Finely Ground Coal Bottom Ash as Replacement for Portland Cement on the Properties of Ordinary Concrete

This study investigates the use of finely ground coal bottom ash (FGCBA) as a substitute for Portland cement in concrete, comparing it with coal fly ash from the same power plant. The incorporation of this ash necessitates the addition of a superplasticizer to achieve the desired slump at the same replacement rate. The results demonstrate that at an optimal 20% replacement rate, as determined by 91-day compressive strength tests, the maximum strength achieved by FGCBA is 97.7% of the control group with pure cement, whereas coal fly ash reaches 114.0%. Drying shrinkage tests indicate for both materials have similar volume stability, while rapid chloride permeability tests show their effectiveness in reducing chloride ion permeability, with superior performance from FGCBA. Under optimal conditions, the result of the RCPT test was only 559 coulombs, which is significantly better compared to the 4108 coulombs when using fly ash from coal combustion. Our results demonstrate that utilizing low-cost bottom ash by finely grinding it to replace Portland cement in concrete is feasible, achieving both carbon reduction and economic viability.

Preparation and Performance of Ultra-Fine High Activity Composite Micronized Powder from Multi-Solid Waste

The composite micronized powder is prepared by using blast furnace slag (BFS), water-quenched manganese slag (WQMS), manganese tailing slag (MTS) and desulfurization gypsum (DG) and grinding aid (GA) through orthogonal test optimization design. The effect of the doping amount of each solid waste on the fluidity, activity at different ages and resistance to chloride ion penetration of the composite micropowder was studied systematically, and the exothermic characteristics of hydration of the composite micropowder with the optimal ratio were tested. The results showed that the amount of MTS dosing was the most significant factor among the four factors on the activity index of composite micronized powder at 7 d and 28 d. The activity index at 28 d decreased and then increased with the increase in MTS dosing; the amount of BFS dosing was the most significant factor affecting the fluidity and chloride ion permeation resistance of composite micronized powder. With an increase in BFS dosing, the fluidity ratio of composite micronized powder increased and then decreased; the electric flux of the matrix decreased, and the chloride ion permeation resistance increased. The optimal ratio of composite powder with the highest 28 d activity is 35% BFS, 30% MTS, 0.3% GA, 5% DG and 30% WQMS. The hydration rate and cumulative heat release of the slurry prepared with the optimal ratio of composite micronized powder to cement (1:1) are lower than those of pure cement slurry. The microstructure of the mortar test block prepared with a 1:1 composite of cement is more compact than that of the pure cement mortar test block, and the pores are fewer.

Investigation of Microstructure and Performance of Ultra-High-Performance Concrete for Transportation Infrastructure

This study examines the engineering properties of ultra-high-performance concrete (UHPC) for use in construction and transportation infrastructure. The UHPC investigated in this study consists of three types of pozzolan, microsilica, nanosilica, and fly ash. It also contains two types of aggregate, garnet and basalt. In addition, it contains steel fibers. The study investigated the properties of fresh UHPC (slump flow, slump flow T50, L-box, and V-funnel), the mechanical properties of UHPC, including compressive and tensile strength, and its durability by analyzing volumetric water absorption, special electrical resistance, and performing the rapid chloride permeability test using scanning electron microscopy to examine the microstructure of UHPC. The results show that UHPC exhibits exceptional mechanical properties, such as high compressive and tensile strengths and remarkable durability, including reduced water absorption, increased special electrical resistance, decreased permeability to chlorine ions, and a negligible permeability range. In conclusion, the study demonstrates that UHPC is a unique material with excellent performance in various engineering applications, making it an ideal choice for construction projects and transportation infrastructures where high strength and long-lasting durability are required.

Effect of CaO/SiO2 and Al2O3/SiO2 on the chloride permeability of one-part alkali-activated nickel slag concrete

To study the effect of CaO/SiO2 and Al2O3/SiO2 ratios on the chloride permeability of one-part alkali-activated nickel slag (AANS) concrete, the chloride ion electromigration coefficient and the distribution of total chlorine concentration at different permeability depths of the one-part AANS concrete were investigated. The ratio of CaO/SiO2 and Al2O3/SiO2 of cement were designed in the range of 0.85–1.3 and 0.3–0.75, respectively. The reaction product and pore structure of paste were analyzed. The Results showed that the total chloride ion concentration in concrete first decreased and then increased with CaO/SiO2 and Al2O3/SiO2 ratios increasing. The chloride permeability of the concrete with CaO/SiO2 of 1.0 and Al2O3/SiO2 of 0.45 was the lowest, as the hydration degree of the concrete was the highest, which effectively optimized the pore structure. The chloride ion migration coefficient of concrete decreased with porosity, and an exponential relationship was observed between the chloride ion migration coefficient with porosity.

Research on a Multi-Objective Optimization Design for the Durability of High-Performance Fiber-Reinforced Concrete Based on a Hybrid Algorithm

To achieve durable high-performance fiber-reinforced concrete that meets economic requirements, this paper introduces a hybrid intelligent framework based on the Latin hypercube experimental design, response surface methodology (RSM), and the NSGA-III algorithm for optimizing the mix design of high-performance fiber-reinforced concrete. The developed framework allows for the prediction of concrete performance and obtains a series of Pareto optimal solutions through multi-objective optimization, ultimately identifying the best mix proportion. The decision variables in this optimization are the proportions of various materials in the concrete mix, with concrete’s frost resistance, chloride ion permeability resistance, and cost as the objectives. The feasibility of this framework was subsequently validated. The results indicate the following: (1) The RSM model exhibits a high level of predictive accuracy, with coefficient of determination (R-squared) values of 0.9657 for concrete frost resistance and 0.9803 for chloride ion permeability resistance. The RSM model can be employed to construct the fitness function for the optimization algorithm, enhancing the efficiency of multi-objective optimization. (2) The NSGA-III algorithm effectively balances durability and cost considerations to determine the optimal mix proportion for the concrete. After multi-objective optimization, the chloride ion permeability resistance and frost resistance of the high-performance fiber-reinforced concrete improved by 38.1% and 6.45%, respectively, compared to the experimental averages, while the cost decreased by 2.53%. The multi-objective optimization method proposed in this paper can be applied to mix design for practical engineering projects, improving the efficiency of concrete mix design.

Machine learning prediction of electric flux in concrete and mix proportion optimization design

This study explored nine machine learning (ML) methods, including linear, nonlinear and integrated learning models, to predict concrete electrical flux metrics reflecting the chloride ion permeability of concrete. Seven concrete mix parameters, including water (W), cement (C), fly ash (FA), ground granulated blast furnace slag (GGBS), fine aggregate (S), coarse aggregate (G) and water reducing admixture (WRA), were used as input parameters. A dataset consisting of 4029 sets of data was used to train and test the prediction model. K-fold cross-validation confirms the model’s accuracy and is performed by R2, MAE, MSE, and RMSE. The results showed that the nonlinear model outperformed the linear model; in particular, the model integrated with learning CatBoost exhibited higher prediction accuracy (R2 = 0.72, RMSE = 0.01, MSE = 0.01, MAE = 0.04). Based on this, a concrete chloride impermeability mix proportion optimization method targeting cost per square is proposed. The proposed model aims to achieve an ideal concrete mix proportion optimization based on ML algorithms and national specifications, which is of great significance to practical engineering.