Pervious concrete (also called porous concrete) is one of the most promising sustainable and green building materials today. This study examined high-strength pervious concrete and ordinary-strength pervious concrete reinforced with steel fiber or glass fiber. A total of fifteen mixtures of normal- and high-strength pervious concretes with steel fiber or glass fiber were used. The goal of high-strength pervious concrete is that the 28-day compressive strength be above 42 MPa and the porosity be as close to 15% as possible to achieve technical specifications. Both normal- and high-strength pervious concretes reinforced with steel fiber (1%, 2%) or glass fiber (0.25%, 0.5%) were investigated in water permeability, porosity, compressive strength, flexural strength, elastic modulus, and toughness tests. The test results show that in both high-strength pervious concrete and ordinary pervious concrete with steel fibers added, the porosity and permeability coefficient are increased compared with the control group. The coefficient of permeability for high-strength, fiber-reinforced pervious concretes with two aggregate sizes meets the requirements of the ACI specification for structural concrete. In addition, the high-strength pervious concrete specimen H1-S2 (2% steel fiber) has the highest compressive strength of 52.8 MPa at the age of 28 days. The flexural strength of pervious concrete also increases with age. However, the flexural strength of fiber-reinforced pervious concrete did not follow this trend due to the large variation in the quality control of different fiber mixtures. However, both steel fiber and glass fiber have a certain degree of improvement in the flexural toughness, and the effect is better with steel fiber. After the flexural strength reaches the peak value, there is still about 30% of the bearing capacity, and it gradually decreases until it is completely destroyed.

In this research, the ability of pervious concrete pavement material to reduce pollutant concentrations and purify water was investigated. This project mainly aims to study the ability of pervious concrete pavement material to reduce pollutant concentrations such as those in diluted sulfuric acid, seawater, and motor oil. The results demonstrated that the ability of pervious concrete pavement material to reduce pollutant concentrations and purify water was effective in diluted sulfuric acid, artificial seawater, and motor oil tests. After flowing through pervious concrete pavement, a diluted sulfuric acid solution (pH value 2.0) could dramatically increase its pH value to approximately 7.0. A pervious concrete pavement system could greatly decrease the content of an artificial seawater solution (salinity 36%) to about 1%, and the oil content of motor oil combined with certain types of water could also be significantly decreased to 1%. The study demonstrates that pervious concrete pavement holds po...

This study was to evaluate the CO₂ curing on mechanical properties of Portland cement concrete. Three different specimen sizes (5 × 10 cm, 10 × 20 cm, and 15 × 30 cm cylinders), three CO₂ concentrations (50%, 75%, 100%), three curing pressures (0.2, 0.4, 0.8 MPa), three curing times (1, 3, 6 h), two water cement ratios (0.41, 0.68) for normal and high-strength concretes, and two test ages (3, 28 days) were used for this investigation. Before using the CO₂ curing process, the concrete samples reached the initial set at approximately 4 h, and the free water in the samples was gradually removed when dry CO₂ gas was injected. The test results show that the 3-day early compressive strength of normal concrete cured by CO₂ is higher than that of concrete cured by water, but the difference is not obvious for high-strength concrete cured by CO₂. In addition, there is a size effect on the strength of the 5 × 10 cm and 15 × 30 cm cylinders, and the strength conversion factor k_s5 value obtained for the 28-day compressive strength is greater than 1.18. Compared to conventional water-cured concrete, the elastic modulus of carbon dioxide-cured one generally increases in proportion to the square root of the 28-day compressive strength. It was observed that there are only minor differences in the four E_C empirical equations obtained by CO₂ curing from 5 × 10 cm and 10 × 20 cm cylinders, respectively.

This study investigated the effects of applying three different types of rejuvenators on a highly aged parking lot pavement, which had shown some severe raveling. Cores were taken from the pavement before and after the treatments to examine the effects of these treatments. Tests were performed to determine the viscosity of the recovered asphalt binders from different layers of the pavement before and after the treatment. Right before coring, the surface texture and skid resistance were measured to assess whether the treatment had adversely affected the frictional properties of the pavement.