Pervious concrete

About: Pervious concrete is a research topic. Over the lifetime, 2920 publications have been published within this topic receiving 27720 citations. The topic is also known as: porous concrete & permeable concrete.

Assessing the phenomenon of clogging of pervious concrete (Pc): Experimental test and model proposition

Abstract: During rainfall, different types of sediments are transported (organic and inorganic) that end up prejudicing the hydraulic efficiency of materials such as pervious concrete (PC). Sediments tend to accumulate on the surface of the material and its internal pore structure causing a decrease in permeability. This phenomenon is known as clogging. This study aims to identify and characterize the phenomenon of clogging of PC considering laboratory and field conditions. In that sense, a PC mix and three types of sediment (sand (S), clay (C), and mixture of both (S + C)) were considered. Two types of permeability tests were adapted to induce the clogging and estimate the permeability reduction: the constant head test (laboratory), and the ASTM C1701 (field). Finally, different rates of clogging (low, medium and high) were considered. Considering the type of sediments, the finer they are the higher is the influence on the clogging phenomenon, reaching maximum permeability reductions greater than 95%. Considering the rate of clogging, the results show that low rate entails higher clogging. On the other hand, an analytical model to describe the clogging was proposed. This predicts efficiently the reduction of permeability considering the type and concentration of sediment. This model was proposed with experimental data obtained and validated with results from other investigations. The model aims to be used for engineers to design PC considering their life span and maintenance.

Mix Design Method for Permeable Base of Porous Concrete

Abstract: As a new material type for permeable base, porous concrete should be designed to maintain both porosity and the structural strength. Based on Talbot's formula and experience, four gradation compositions of porous concrete are designed with consideration of effective particle size and uniform coefficient as effective descriptive targets for the aggregate gradation. Three factors, including cement dosage, water cement ratio and aggregate gradation, are considered in an orthogonal test. Statistical variance analysis of the tests results showed that, at a confidence probability of 95%, the factors that significantly influence the 7-day compressive strength are gradation and cement aggregate ratio while the factor that significantly influences effective porosity at the same confidence probability is the cement aggregate ratio. In addition, when the confidence probability is 90%, gradation, cement dose and water cement ratio all have significant influence on the 7-day compressive strength and the effective porosity. Based on the test results, a series of regression relationships of 7-day compressive strength and effective porosity of porous concrete are derived. Finally, an empirical equation for mixture design of porous concrete is proposed.

Performance Assessment of Portland Cement Pervious Pavement

Abstract: A pervious concrete shoulder was constructed along a rest stop on Interstate 4 in central Florida. The shoulder was 90 feet long and 10 feet wide. The depth of pervious concrete was 10 inches. A 12 inch deep reservoir consisting of select pollution control materials was used beneath the pervious concrete. The shoulder was monitored over a one year period for wear and stormwater management. The shoulder was monitored for traffic counts recording approximately 500 axles per week. This use included stopping and starting and sometimes the stops were rapid as the truckers did prefer to park on the hard surface pervious concrete area. There was no visual wear noted on the concrete. An embedded single ring infiltrometer was used to monitor the infiltration rates. The rate of infiltration did not decrease with time. The average rates of infiltration over one year were 2.5 inches per hour at a head of zero to one inch; 4.8 inches per hour at a six inch head; and 6.3 inches per hour at a nine inch head. An acceptable rate of infiltration for these designs is 1.5 inches per hour. Water quality leaving the reservoir was about equal to rainwater quality. The amount of water from the collection pipe nearest the edge of pavement was about 50 times the volume from the collection pipe seven feet from the edge of pavement. The demonstration using pervious concrete was considered a success based on wear, water quantity, and water quality considerations. It is recommended for other similar locations.

Experimental study on rainfall-runoff relation for porous pavements

Abstract: Impervious surfaces have long been implicated in the decline of watershed integrity in urban and urbanizing areas. Porous pavement is one solution to mitigating the problem of stormwater runoff problems. In this research, three available porous pavement systems were investigated to evaluate their infiltration capability of precipitation. Experiments were conducted to simulate different kinds of porous pavements having different sub-base materials in different cells. The discharge volumes were monitored from each cell, and the relationship between rainfall intensity, outflow and outflow duration was analyzed. Results show that these three porous pavements increased infiltration and decreased runoff. The optimum thickness of the porous pavement was 31 cm, which consisted of a 6 cm top layer of porous concrete and a 25 cm sub-base (10 cm concrete without sand and 15 cm aggregate base). Furthermore, under a rainfall rate of 59.36 mm/h, the runoff coefficient of the above porous pavement was zero, while the coefficient of the impervious pavement was 0.85. These results provide a clear indication of the value of porous pavement systems for broad expanses of the human engineered environment.