Durability Performance and Corrosion Mechanism of New Basalt Fiber Concrete under Organic Water Environment

Under corrosive environments, concrete material properties can deteriorate significantly, which can seriously affect structural safety. Therefore, it has important engineering applications to improve the durability performance at a lower economic cost. This paper proposes a new, highly durable concrete using inexpensive construction materials such as basalt fiber, sodium methyl silicate, and inorganic aluminum salt waterproofing agent. With the massive application of sewage treatment projects, the problem of concrete durability degradation is becoming more and more serious. In this paper, five types of concrete are developed for the sewage environment, and the apparent morphology and fine structure of the specimens after corrosion in sewage were analyzed. The density, water absorption, and compressive strength were measured to investigate the deterioration pattern of concrete properties. It was found that ordinary concrete was subject to significant corrosion, generating large deposits of algae on the surface and accompanied by sanding. The new concrete showed superior corrosion resistance compared to conventional concrete. Among other factors, the inorganic aluminum salt waterproofing agent effect was the most prominent. The study found that the strength of ordinary concrete decreased by about 15% in the test environment, while the new concrete had a slight increase. Comprehensive evaluation showed that the combination of basalt fiber and inorganic aluminum salt waterproofing agent had the best effect. Its use is recommended.


Introduction
Concrete structures serving in harsh environments give rise to huge annual losses due to insufficient durability. With the development of the modern city, the demand for water treatment structure is strong. As a typical corrosive environment, sewage has caused serious corrosion to structures such as sewage tanks and pipelines, greatly shortening their service life and increasing maintenance costs, resulting in immeasurable economic losses. Therefore, it is urgent to improve the durability of concrete in sewage environment.
Domestic and foreign research has been conducted for a long time to explore the corrosion mechanism of sewage on concrete, both physicochemical corrosion [1,2], and microbial corrosion [3][4][5]. Concrete corrosion is mainly affected by microbial redox generation of H 2 S and biological sulfuric acid corrosion [6,7]. Scholars have carried out in-depth studies for H 2 S, biological sulfuric acid corrosion in sewage. Li [8], Jiang [9] et al. studied the effects of H 2 S and relative humidity on concrete sewer corrosion. The results show that the corrosion rates in the gas phase and partially submerged concrete specimens are positively correlated with the concentration of H 2 S, and high relative humidity affects the specimens in the gas phase. Sun et al. [10,11] found that a high concentration of H 2 S impairs the oxidation of sulfide in the pipe, making the concrete surface sulfide absorption decrease after the first increase. Min et al. [12] studied the effect of sulfuric acid pH on concrete corrosion, and the results showed that sulfuric acid corrosion of concrete was most severe when the pH was 2.5. Mahmoodian et al. [13] studied the effect of sulfuric acid concentration and temperature. They found that: the more acidic the solution, the more serious the corrosion, but the The test block was immersed in artificially configured high-concentration organic water, and the high-concentration artificial sewage mix ratio is shown in Table 2. In the test, a batch of test blocks were taken out every 60 d for macro and micro index tests. In the future, advanced machines and network technologies can be used to monitor the test process, scientifically analyze the data, and finally compare it with the test results to get the most rigorous conclusions [36,37].  6 20 Note: For every 20 kg of clear water, add 1 kg of sludge + 1 kg of algae-rich water as the biologic source.

Corrosion Tests
The test will be of five different ratio test blocks immersed in organic water solution. Every 60 d, part of the test blocks is taken out, to observe the corrosion of the test blocks. The changes in the phenological phenomena of concrete with increasing corrosion cycles are shown in Figure 1. The surface darkening (algae deposition) of concrete of each ratio is crystallized. Comparing the appearance of concrete with different ratios at the same age, it is found that C1 and C2 have more crystallization on the surface, and the amount of crystallization decreases with the increase of corrosion time. A small amount of crystallization was found on the surface of C3-C5 concrete, with the least amount of crystallization in C4. By 240 d, the apparent damage of C1 was more severe, and the edges were peeling off. The C2 surface was lightly sanded, C3 and C4 were intact and less affected by corrosion, C5 surface was severely sanded and had powder peeling off. By comparing the apparent corrosion phenomenon, we found that adding basalt fiber, mineral admixture, and water repellent can effectively stop the concrete from being eroded and improve the durability performance of the material. are shown in Figure 1. The surface darkening (algae deposition) of concrete of each ratio is crystallized. Comparing the appearance of concrete with different ratios at the same age, it is found that C1 and C2 have more crystallization on the surface, and the amount of crystallization decreases with the increase of corrosion time. A small amount of crystallization was found on the surface of C3-C5 concrete, with the least amount of crystallization in C4. By 240 d, the apparent damage of C1 was more severe, and the edges were peeling off. The C2 surface was lightly sanded, C3 and C4 were intact and less affected by corrosion, C5 surface was severely sanded and had powder peeling off. By comparing the apparent corrosion phenomenon, we found that adding basalt fiber, mineral admixture, and water repellent can effectively stop the concrete from being eroded and improve the durability performance of the material.

Strength Tests
Compressive strength can reflect to a certain extent the concrete test block bearing capacity. The strength test was carried out on the test blocks by taking test blocks out every 60 d to observe the effect of corrosion solution on the bearing capacity of concrete with different ratios. The compressive strength test is based on the "Standard for Mechanical Properties Test Methods of General Concrete", and three test blocks are taken from each group for compressive strength (taking the average value). The testing machine (Shanghai Hualong Testing Instruments Co., Shanghai, China)with displacement control

Strength Tests
Compressive strength can reflect to a certain extent the concrete test block bearing capacity. The strength test was carried out on the test blocks by taking test blocks out every 60 d to observe the effect of corrosion solution on the bearing capacity of concrete with different ratios. The compressive strength test is based on the "Standard for Mechanical Properties Test Methods of General Concrete", and three test blocks are taken from each group for compressive strength (taking the average value). The testing machine (Shanghai Hualong Testing Instruments Co., Shanghai, China)with displacement control was loaded at a rate of 0.45 mm/min and stopped loading when the specimens reached 75% of the maximum load-bearing capacity.
The mechanical test of the compressive strength of the concrete after corrosion was carried out. It can be seen from Figure 2 that ordinary concrete C1 has penetrating cracks at the edge, the top is crushed, and a small amount of concrete falls off. Compared with C1, the integrity of the test blocks of C2, C3, and C5 is obviously improved after the compressive test, but the surface has different degrees of damage, mainly fine cracks. C4 has the best overall appearance, with only minor cracks. In the process of compressive tests of concrete, the time from crack to failure of ordinary concrete is very short, due to brittle failure. Comparing the failure process and phenomenon of concrete test blocks with the same age and different proportions horizontally, it can be found that adding basalt fiber can improve the failure form and integrity of concrete after failure and improve the compressive strength of concrete after corrosion. Through the damage of concrete in the strength test, it is found that C4 has the best compressive performance, followed by C3 and C5, which laterally indicates that after adding inorganic aluminum salts, the corrosion resistance of concrete is improved and the compressive strength is enhanced, which is consistent with the conclusions obtained from the corrosion test.
capacity. The strength test was carried out on the test blocks by taking test blocks out every 60 d to observe the effect of corrosion solution on the bearing capacity of concrete with different ratios. The compressive strength test is based on the "Standard for Mechanical Properties Test Methods of General Concrete", and three test blocks are taken from each group for compressive strength (taking the average value). The testing machine (Shanghai Hualong Testing Instruments Co., Shanghai, China)with displacement control was loaded at a rate of 0.45 mm/min and stopped loading when the specimens reached 75% of the maximum load-bearing capacity.
The mechanical test of the compressive strength of the concrete after corrosion was carried out. It can be seen from Figure 2 that ordinary concrete C1 has penetrating cracks at the edge, the top is crushed, and a small amount of concrete falls off. Compared with C1, the integrity of the test blocks of C2, C3, and C5 is obviously improved after the compressive test, but the surface has different degrees of damage, mainly fine cracks. C4 has the best overall appearance, with only minor cracks. In the process of compressive tests of concrete, the time from crack to failure of ordinary concrete is very short, due to brittle failure. Comparing the failure process and phenomenon of concrete test blocks with the same age and different proportions horizontally, it can be found that adding basalt fiber can improve the failure form and integrity of concrete after failure and improve the compressive strength of concrete after corrosion. Through the damage of concrete in the strength test, it is found that C4 has the best compressive performance, followed by C3 and C5, which laterally indicates that after adding inorganic aluminum salts, the corrosion resistance of concrete is improved and the compressive strength is enhanced, which is consistent with the conclusions obtained from the corrosion test.

SEM Electron Microscopy Scan
Concrete pore structure changes after corrosion. Figure 3 shows that after eight months of corrosion of the concrete surface cement stone, the structure has become loose and porous. C1 has more pores, mainly large pores. C2 has medium and small pores, but the number is less than for C1. It can be seen that the basalt fiber and mineral admixture can slow down the corrosion of the concrete and improve corrosion resistance. C3, C4 cement stone structure does not change much over the period; it is still relatively dense. C4 denseness is the best, indicating that a single admixture of sodium methyl silicate and inorganic aluminum salt waterproofing agent can effectively improve the corrosion resistance of concrete. C5 shows a small, medium and large pores fragmented distribution,

SEM Electron Microscopy Scan
Concrete pore structure changes after corrosion. Figure 3 shows that after eight months of corrosion of the concrete surface cement stone, the structure has become loose and porous. C1 has more pores, mainly large pores. C2 has medium and small pores, but the number is less than for C1. It can be seen that the basalt fiber and mineral admixture can slow down the corrosion of the concrete and improve corrosion resistance. C3, C4 cement stone structure does not change much over the period; it is still relatively dense. C4 denseness is the best, indicating that a single admixture of sodium methyl silicate and inorganic aluminum salt waterproofing agent can effectively improve the corrosion resistance of concrete. C5 shows a small, medium and large pores fragmented distribution, and a slightly loose structure, indicating that double admixture of sodium methyl silicate and inorganic aluminum salt waterproofing agent on the corrosion resistance of concrete has a weakening effect. The addition of mineral admixture has a significant impact on reducing the structural porosity and improving the compactness. C1 is ordinary concrete with significant internal defects and more gaps. In addition, after the corrosion of the organic aqueous solution, harmful ions infiltrate through the cracks and react with the cement hydration products, causing some of the cementitious materials to fall off and increasing the pores of C1. This is accompanied by a large number of harmful substances entering the concrete and causing internal corrosion, further increasing the porosity and reducing the compactness, so the phenomenon of C1 damage during corrosion is evident. The strength test under the C1 compressive capacity is also the weakest; in contrast, the C4 structure is dense and less porous, so the apparent damage phenomenon is lighter, and the compressive strength is the highest. months of corrosion of the concrete surface cement stone, the structure has be and porous. C1 has more pores, mainly large pores. C2 has medium and smal the number is less than for C1. It can be seen that the basalt fiber and minera can slow down the corrosion of the concrete and improve corrosion resista cement stone structure does not change much over the period; it is still relati C4 denseness is the best, indicating that a single admixture of sodium methyl inorganic aluminum salt waterproofing agent can effectively improve the co sistance of concrete. C5 shows a small, medium and large pores fragmented d and a slightly loose structure, indicating that double admixture of sodium me and inorganic aluminum salt waterproofing agent on the corrosion resistance has a weakening effect. The addition of mineral admixture has a significan reducing the structural porosity and improving the compactness. C1 is ordina with significant internal defects and more gaps. In addition, after the corrosio ganic aqueous solution, harmful ions infiltrate through the cracks and react w ment hydration products, causing some of the cementitious materials to fall creasing the pores of C1. This is accompanied by a large number of harmful entering the concrete and causing internal corrosion, further increasing the p reducing the compactness, so the phenomenon of C1 damage during corrosion The strength test under the C1 compressive capacity is also the weakest; in c C4 structure is dense and less porous, so the apparent damage phenomeno and the compressive strength is the highest.  The SEM microstructure of the concrete after 240 d of corrosion by organic aqueous solution is shown in Figure 4. C1 and C2 were loose on the surface, generating a large number of needle-like ettringite crystals, and almost no Ca(OH) 2 crystals were observed; both generated deep cracks, but the basalt fibers in C2 inhibited the development of cracks. Hexagonal plate-like Ca(OH) 2 crystals can be observed in C3 and C4 test blocks, and their internal structures are relatively dense. It shows that adding sodium methyl silicate and inorganic aluminum salt waterproofing agents can effectively improve the corrosion resistance of concrete in a sewage environment. Fibers can also be observed crossing in C4, which are tightly connected to the structure. However, C5, double-doped with sodium methyl silicate and inorganic aluminum salt water repellent, has a slightly loose structure and ettringite formation. The production of calcium alumina in C1 and C2 indicates the intrusion of SO 4 2− ions, causng a reaction with hydration products, while a large amount of Ca(OH) 2 in C3 and C4 means that sodium methyl silicate and inorganic aluminum salt water repellent can both promote cement hydration and block the infiltration of harmful substances, ensuring that the corrosion resistance of the material is improved.
indicates the intrusion of SO4 2− ions, causng a reaction with hydration products, w large amount of Ca(OH)2 in C3 and C4 means that sodium methyl silicate and inor aluminum salt water repellent can both promote cement hydration and block the in tion of harmful substances, ensuring that the corrosion resistance of the material i proved.

X-Ray Diffraction
From Figure 5, it can be seen that the diffraction peak of ettringite in C1 is higher that of all the other matching concrete. SO4 2− reacts with cement hydration produ form ettringite. Ettringite will produce expansion stress and damage the internal stru of concrete, which is also the main reason for concrete damage. Therefore, the compre strength of C1 is the lowest. A small amount of ettringite was detected in C2, an content of Ca(OH)2 decreased with the increase of corrosion, but it was still the main ponent. The diffraction peaks of C2S and C3S in C3 and C4 decreased significantly diffraction peak of Ca(OH)2 was very high, and ettringite was not detected. This s that incorporating sodium methyl silicate and inorganic aluminum salt waterpro agent is beneficial to cement hydration and effectively prevents the entry of SO4 2− diffraction peaks of C2S and C3S in C5 get lower and lower. It can be seen that the d mixing of sodium methyl silicate and inorganic aluminum salt waterproofing agent more apparent promoting effect on cement hydration. Still, a small amount of ettring produced. It is possible that the double-doped waterproofing agent has a weakened on their respective barrier effects and does not achieve the barrier effect of 1 + 1 > 2

X-ray Diffraction
From Figure 5, it can be seen that the diffraction peak of ettringite in C1 is higher than that of all the other matching concrete. SO 4 2− reacts with cement hydration products to form ettringite. Ettringite will produce expansion stress and damage the internal structure of concrete, which is also the main reason for concrete damage. Therefore, the compressive strength of C1 is the lowest. A small amount of ettringite was detected in C2, and the content of Ca(OH) 2 decreased with the increase of corrosion, but it was still the main component. The diffraction peaks of C 2 S and C 3 S in C3 and C4 decreased significantly; the diffraction peak of Ca(OH) 2 was very high, and ettringite was not detected. This shows that incorporating sodium methyl silicate and inorganic aluminum salt waterproofing agent is beneficial to cement hydration and effectively prevents the entry of SO 4 2− . The diffraction peaks of C 2 S and C 3 S in C5 get lower and lower. It can be seen that the double mixing of sodium methyl silicate and inorganic aluminum salt waterproofing agent has a more apparent promoting effect on cement hydration. Still, a small amount of ettringite is produced. It is possible that the double-doped waterproofing agent has a weakened effect on their respective barrier effects and does not achieve the barrier effect of 1 + 1 > 2. The generation of ettringite will have a certain impact on the strength of concrete, which is consistent with the conclusion of the compressive strength values obtained.

Density and Water Absorption
Density and water absorption tests were conducted for each concrete mixing ratio after corrosion, and the results were as follows. The concrete density variation is shown in Figure 6. Overall, the concrete density shows a trend of increasing and then decreasing. It indicates that the crevices in the internal structure first reduce and then grow. The reason is that in the early stage of corrosion, the salt ions in the organic aqueous solution enter the concrete through the gaps. The precipitated crystals fill the internal pores, making the structure dense. Since the accumulation of microorganisms in organic aqueous

Density and Water Absorption
Density and water absorption tests were conducted for each concrete mixing ratio after corrosion, and the results were as follows. The concrete density variation is shown in Figure 6. Overall, the concrete density shows a trend of increasing and then decreasing. It indicates that the crevices in the internal structure first reduce and then grow. The reason is that in the early stage of corrosion, the salt ions in the organic aqueous solution enter the concrete through the gaps. The precipitated crystals fill the internal pores, making the Materials 2023, 16, 452 9 of 16 structure dense. Since the accumulation of microorganisms in organic aqueous solution is not enough, the mass loss caused by the corrosion of concrete by the biological acid it produces is not enough to offset the mass of the crystals precipitated in the pores, so the density of concrete increases first. By the late stage of corrosion, with the accumulation of biological acids in the solution, the corrosion of the concrete structure increases, and the mass loss increases significantly, so the density decreases. Figure 7, the water absorption of the concrete test blocks shows a trend of decreasing and then increasing. The water absorption laterally reflects the porosity of the concrete structure, indicating that the pores in the structure first decrease and then increase. It is consistent with the conclusion obtained from the density of the concrete.

As shown in
The cross-sectional comparison revealed that the compactness of C2 was better than that of C1, indicating that adding mineral admixtures can fill the pores in the concrete and make the concrete structure more compact than ordinary concrete. The fibers can inhibit the generation and development of cracks while improving the corrosion resistance of the concrete. The concrete densities in the C3, C4, and C5 mixes were consistently higher, and the water absorption rates were lower. Adding sodium methyl silicate and inorganic aluminum salt water repellent is beneficial to reduce internal defects, increase compactness, and improve concrete's corrosion resistance.   As shown in Figure 7, the water absorption of the concrete test blocks shows a trend of decreasing and then increasing. The water absorption laterally reflects the porosity of the concrete structure, indicating that the pores in the structure first decrease and then increase. It is consistent with the conclusion obtained from the density of the concrete. so the density of concrete increases first. By the late stage of corrosion, with the accumulation of biological acids in the solution, the corrosion of the concrete structure increases, and the mass loss increases significantly, so the density decreases.
As shown in Figure 7, the water absorption of the concrete test blocks shows a trend of decreasing and then increasing. The water absorption laterally reflects the porosity of the concrete structure, indicating that the pores in the structure first decrease and then increase. It is consistent with the conclusion obtained from the density of the concrete.
The cross-sectional comparison revealed that the compactness of C2 was better than that of C1, indicating that adding mineral admixtures can fill the pores in the concrete and make the concrete structure more compact than ordinary concrete. The fibers can inhibit the generation and development of cracks while improving the corrosion resistance of the concrete. The concrete densities in the C3, C4, and C5 mixes were consistently higher, and the water absorption rates were lower. Adding sodium methyl silicate and inorganic aluminum salt water repellent is beneficial to reduce internal defects, increase compactness, and improve concrete's corrosion resistance.   The cross-sectional comparison revealed that the compactness of C2 was better than that of C1, indicating that adding mineral admixtures can fill the pores in the concrete and make the concrete structure more compact than ordinary concrete. The fibers can inhibit the generation and development of cracks while improving the corrosion resistance of the concrete. The concrete densities in the C3, C4, and C5 mixes were consistently higher, and the water absorption rates were lower. Adding sodium methyl silicate and inorganic aluminum salt water repellent is beneficial to reduce internal defects, increase compactness, and improve concrete's corrosion resistance.

Intensity
Tests were conducted to test the compressive strength of the concrete after corrosion, and the following results were obtained. The load-displacement curve of each mixing ratio test block is shown in Figure 8. Concrete compressive strength and ductility are significantly improved by adding basalt fiber, the mineral admixture and waterproofing agent. At 0 d, compared with C1, concrete's maximum compressive bearing capacity with other mix ratios is greatly improved. It can be seen that mineral admixtures can fill pores, increase compactness and improve compressive ability. The displacement of concrete damage is extended, indicating that the ductility has been enhanced. Adding basalt fiber will improve the deformation capacity of concrete. With the increase of corrosion time, the bearing capacity decreases, and the biological acid in the organic aqueous solution corrodes the concrete to produce expansive substances, which reduces the strength; at the same time, the deformation capacity of concrete has fallen, from a displacement maximum of 3 mm down to about 2 mm.

Intensity
Tests were conducted to test the compressive strength of the concrete after corrosion, and the following results were obtained. The load-displacement curve of each mixing ratio test block is shown in Figure 8. Concrete compressive strength and ductility are significantly improved by adding basalt fiber, the mineral admixture and waterproofing agent. At 0 d, compared with C1, concrete's maximum compressive bearing capacity with other mix ratios is greatly improved. It can be seen that mineral admixtures can fill pores, increase compactness and improve compressive ability. The displacement of concrete damage is extended, indicating that the ductility has been enhanced. Adding basalt fiber will improve the deformation capacity of concrete. With the increase of corrosion time, the bearing capacity decreases, and the biological acid in the organic aqueous solution corrodes the concrete to produce expansive substances, which reduces the strength; at the same time, the deformation capacity of concrete has fallen, from a displacement maximum of 3 mm down to about 2 mm. The strength of concrete after corrosion is shown in Table 3. After 240 days of corrosion, the strength retention rate of ordinary concrete C1 is 85.86%, and the residua strength is 46.52 MPa. Compared with C1, the residual strength and strength retention rate of the other four groups is improved. Among them, C4 has the highest strength retention rate, 1.18 times that of C1; the residual strength is 60.79 MPa, 1.3 times that of C1 The strength retention rate and residual strength increased by 18% and 30%, respectively After 240 days of corrosion, the strength has almost no attenuation. It can be seen that the inorganic aluminum salt waterproof agent has the best corrosion resistance effect on concrete. The strength retention rate of C3 and C5 doped with sodium methyl silicate is not as good as C4, but compared with C1, the strength retention rate is also increased by about 10%. Compared with C1, the strength retention rate of C2 increased significantly, indicating that basalt fiber and mineral admixtures can effectively resist sewage corrosion. Figure 9 shows the spatial variation of concrete strength. They corresponded to the data in Table 3. It can be seen that the strength of concrete increases first and then decreases with the increase of corrosion time, indicating that the internal porosity decreases first and then increases. Combined with the analysis of density change, it can be seen that the strength of concrete is related to density. The higher the density, the higher the strength.
To sum up, the plastic deformation ability is obviously improved by adding basalt fiber to concrete. Sodium methyl silicate and inorganic aluminum salt waterproofing agents can effectively improve concrete's mechanical properties and corrosion resistance  The strength of concrete after corrosion is shown in Table 3. After 240 days of corrosion, the strength retention rate of ordinary concrete C1 is 85.86%, and the residual strength is 46.52 MPa. Compared with C1, the residual strength and strength retention rate of the other four groups is improved. Among them, C4 has the highest strength retention rate, 1.18 times that of C1; the residual strength is 60.79 MPa, 1.3 times that of C1. The strength retention rate and residual strength increased by 18% and 30%, respectively. After 240 days of corrosion, the strength has almost no attenuation. It can be seen that the inorganic aluminum salt waterproof agent has the best corrosion resistance effect on concrete. The strength retention rate of C3 and C5 doped with sodium methyl silicate is not as good as C4, but compared with C1, the strength retention rate is also increased by about 10%. Compared with C1, the strength retention rate of C2 increased significantly, indicating that basalt fiber and mineral admixtures can effectively resist sewage corrosion.  Figure 9 shows the spatial variation of concrete strength. They corresponded to the data in Table 3. It can be seen that the strength of concrete increases first and then decreases with the increase of corrosion time, indicating that the internal porosity decreases first and then increases. Combined with the analysis of density change, it can be seen that the strength of concrete is related to density. The higher the density, the higher the strength.
Materials 2023, 16, x FOR PEER REVIEW 12 Figure 9. Spatial distribution of compressive strength.

Discussion
The composition of the organic aqueous solution is complex, and concrete struct are easily eroded. The initial concrete surface is alkaline, and the solution contains su ions, which are converted into H2S by anaerobic sulfate-reducing bacteria (SRB). H further combined with oxygen to form H2SO4. These acidic compounds are neutral with concrete so that the pH value of the concrete surface is gradually reduced. When pH value is close to 4, the acidophilic SOB (ASOB) bacteria (such as Acidithiobacillu rooxidans and Acidithiobacillus thiooxidans) begin to multiply in large quantities, which produce concentrated biological sulfuric acid, further acidify the environment, and form biological sulfuric acid corrosion, which is the main reason for the deterioratio concrete performance.
Concrete contains many calcium compounds (such as calcium hydroxide, C-S-H cium aluminate). Biosulfuric acid will initially react with Ca(OH)2 and later react wit S-H gel to form gypsum, reducing the structural strength and increasing porosity. gypsum will continue to react with hydrated calcium aluminate to create swelling ettr ite, which will generate internal stress and eventually cause concrete cracking, as sh in Figure 10.
To lessen the deterioration of concrete performance, two kinds of waterproo agents, sodium methyl silicate and inorganic aluminum salt, were added to preven penetration of harmful substances and protect concrete from corrosion. Sodium me silicate can form a layer of impermeable waterproof resin film on the surface of cem based materials, as shown in Figure 11. Inorganic aluminum salt waterproof agent generate an impermeable double salt inside the cement base, fill the pores, form a waterproof layer, and effectively prevent harmful substances from entering, as show Figure 12. Finally, remote sensing technology can be used for real-time monito through the network to keep abreast of structural damage and reduce engineering lo [38][39][40]. To sum up, the plastic deformation ability is obviously improved by adding basalt fiber to concrete. Sodium methyl silicate and inorganic aluminum salt waterproofing agents can effectively improve concrete's mechanical properties and corrosion resistance.

Discussion
The composition of the organic aqueous solution is complex, and concrete structures are easily eroded. The initial concrete surface is alkaline, and the solution contains sulfate ions, which are converted into H 2 S by anaerobic sulfate-reducing bacteria (SRB). H 2 S is further combined with oxygen to form H 2 SO 4 . These acidic compounds are neutralized with concrete so that the pH value of the concrete surface is gradually reduced. When the pH value is close to 4, the acidophilic SOB (ASOB) bacteria (such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans) begin to multiply in large quantities, which will produce concentrated biological sulfuric acid, further acidify the environment, and then form biological sulfuric acid corrosion, which is the main reason for the deterioration of concrete performance.
Concrete contains many calcium compounds (such as calcium hydroxide, C-S-H, calcium aluminate). Biosulfuric acid will initially react with Ca(OH) 2 and later react with C-S-H gel to form gypsum, reducing the structural strength and increasing porosity. The gypsum will continue to react with hydrated calcium aluminate to create swelling ettringite, which will generate internal stress and eventually cause concrete cracking, as shown in Figure 10.   To lessen the deterioration of concrete performance, two kinds of waterproofing agents, sodium methyl silicate and inorganic aluminum salt, were added to prevent the penetration of harmful substances and protect concrete from corrosion. Sodium methyl silicate can form a layer of impermeable waterproof resin film on the surface of cementbased materials, as shown in Figure 11. Inorganic aluminum salt waterproof agent can generate an impermeable double salt inside the cement base, fill the pores, form a rigid waterproof layer, and effectively prevent harmful substances from entering, as shown in Figure 12. Finally, remote sensing technology can be used for real-time monitoring through the network to keep abreast of structural damage and reduce engineering losses [38][39][40].
Schematic diagram of the action model of sodium methyl silicate:     Figure 12. Inorganic aluminum salt waterproofing agent role model.

Conclusions
The following conclusions were mainly obtained by studying new basalt fiber concrete's durability performance and corrosion mechanism under an organic water environment.
(1) After organic water solution corrosion, there are a lot of black algae deposits and crystallization on the concrete surface, and there is a sanding phenomenon. The addition of sodium methyl silicate and inorganic aluminum salt water repellent led to an improvement in the concrete surface corrosion. The effect of adding inorganic aluminum salt waterproofing agent is more prominent. (2) Through microscopic analysis, it is found that there are many pores in ordinary concrete, and the pores of other mix ratios are significantly reduced. Among them, the test block with added inorganic aluminum salt waterproof agent is the most compact. (3) The compressive strength analysis shows that the addition of inorganic aluminum salt waterproofing agent can increase the strength of the material by about 12% and the strength retention rate by 15%. The combination of basalt fiber and inorganic aluminum salt waterproofing agent has the best effect. It is recommended to be used in preference to normal concrete. (4) The addition of an inorganic aluminum salt waterproofing agent significantly reduced corrosion and improved the durability of concrete materials in a sewage environment corrosion; the recommended dose of 6 kg/m 3 . (5) This new highly durable concrete protection mechanism relies on basalt fiber and inorganic aluminum salt waterproofing agent, the addition of which causes filling of the internal pores, increased density of concrete materials and reduced rate of penetration of harmful substances. Sodium methyl silicate and cement-based materials react to form a specific waterproof layer, blocking ion penetration; however, the inorganic aluminum salt waterproofing agent protection effect is more prominent.

Conflicts of Interest:
The authors declare that they have no conflict of interest.