Permeability Resistance Of Concrete Research Articles

A Comprehensive Review on Water Permeability Testing and Sealing Techniques in Concrete Construction

The durability of concrete is determined by the permeability resistance to a large extent. The permeability resistance of concrete is an important index of concrete durability. This paper introduces the water permeability test process of concrete in China, Europe and the United States, and explains the sealing method of specimens in the water permeability test of concrete according to the Chinese standard, so that the construction inspection industry personnel can choose according to the actual situation of the project and the evaluation needs.

Development of Ductile and Durable High Strength Concrete (HSC) through Interactive Incorporation of Coir Waste and Silica Fume.

The issue of brittleness and low post-peak load energy associated with the plain HSC led to the development of fiber-reinforced concrete (FRC) by using discrete fiber filaments in the plain matrix. Due to the high environmental impact of industrial fibers and plasticizers, FRC development is ecologically challenged. Sustainability issues demand the application of eco-friendly development of FRC. This study is aimed at the evaluation of coir as a fiber-reinforcement material in HSC, with the incorporation of silica fume as a partial replacement of cement. For this purpose, a total of 12 concrete mixes were produced by using three different doses of coir (0%, 1%, 1.5%, and 2% by wt. of binder) with silica fume (0%, 5%, and 10% as volumetric replacements of cement). The examined parameters include compressive strength, shear strength, splitting tensile strength, ultrasonic pulse velocity, water absorption, and chloride ion permeability. The scanning electron microscopy (SEM) technique was adopted to observe the microstructure of the CF-reinforced concrete. The results revealed that due to the CF addition, the compressive strength of HSC reduces notably; however, the splitting tensile strength and shear strength experienced notable improvements. At the combined incorporation of 1.5% CF with 5% silica fume, the splitting tensile strength and shear strength of the concrete experienced improvements of 47% and 70%, respectively, compared to that of the control mix. The CF incorporation is detrimental to the imperviousness of concrete. The combined incorporation of CF and silica fume is recommended to minimize the negative effects of CF on the permeability resistance of concrete. The SEM results revealed that CF underwent a minor shrinkage with the age.

Influence of different surface treatment on water penetration resistance of concrete

Concrete is easily affected by all kinds of erosive substances during its use. Surface treatment is a simple method to improve the surface compactness and water permeability resistance of concrete. In this paper, silicate infiltration agent, nano-SiO2 and ethyl silicate are selected as concrete surface treatment material. The results of water permeability test showed that all the three treatments can effectively improve the water resistance. Silicate infiltration agent and nano-SiO2 were the most effective, which greatly reduced the penetration depth of water from 66 mm to 34mm and 32 mm, while ethyl silicate was reduced to 50 mm. Through the water permeability test curve, we can see that the water entered the concrete under a certain pressure, and the result showed the shape of high, middle and low edge.

Experimental Study and Analysis on the Durability of Concrete in Underground Engineering

The underground environment is much more complicated than the overground environment. Concrete in underground engineering bears complex environmental effects such as soil stress, water penetration stress, and soil salt erosion. The durability of concrete directly determines the service life of underground engineering. In this paper, considering the soil stress, the chloride ion, sulfate attack and permeability resistance of concrete were tested in the laboratory. The results show that fly ash has excellent resistance to sulfate attack, and when fly ash content is 20% or 30%, the concrete specimens have the best chloride ion penetration resistance and water penetration resistance. Under the effect of preload stress, when the preload stress level is less than 20%, the capacity of concrete stress cannot be reduced greatly, but when the preload stress level is greater than 20%, the concrete durability performance decreases rapidly.

Thermal performance and corrosion resistance of structural-functional concrete made with inorganic PCM

Over the last few years, phase change materials (PCMs) have been proved capable to improve the thermal performance of cement-based materials. However, the issues of inorganic PCM leakage and corrosion have led to apprehension. The present study aims to investigate the feasibility of using a dual-layer coating system to improve leakage and corrosion resistance of concrete made of macro-encapsulated inorganic PCM-lightweight aggregate (PCM-LWA). The coated PCM-LWA system is referred to thermal energy storage aggregate (TESA). The effect of TESA at different volume fractions on mechanical, thermal and corrosion performances of concrete were investigated. Test results indicated that the compressive strength of TESA concrete reduced by 6–9% compared to the LWA concrete. However, TESA concrete did not lose strength when subjected to thermal cycles between 15 and 40 °C, which represents the thermal reliability of TESA system. The thermogravimetry analysis and differential scanning calorimeter test results indicated that the PCM was thermally stable and reliable. The thermal performance test demonstrated the feasibility and functionality of using TESA in concrete structures. Infrared thermography camera indicated that the surface temperature of TESA concrete was lower than that of the control mixture. The accelerated corrosion test demonstrated the significant role of the dual-layer coating system, which can reduce the leakage of PCM and avoid the detrimental impact of inorganic PCM on the corrosion of reinforcing steel. Besides, the permeability resistance of concrete was improved using TESA.