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.

Mechanical and durability characteristics of pervious concrete reinforced with mechanically recycled carbon fiber composite materials

Abstract: A more durable pervious concrete was produced using mechanically processed carbon fiber composite scraps from the aerospace industry, referred to as cured carbon fiber composite materials (CCFCMs). The processed CCFCM were fiber-like shreds with large aspect ratios and were a composite of carbon fibers reinforcing the thermoset resin. CCFCMs were used as 0.5, 1, 2 vol% replacement of natural coarse aggregate in a low-porosity (well packed) pervious concrete with pea gravel. Mechanical and durability evaluation was performed compared to two baseline mixes, a neat mix with zero CCFCM (control) and a mix with 0.5 vol% replacement with commercial synthetic fibers (POLY-0.5). CCFCMs disturbed the packing arrangement of natural aggregate and resulted in higher porosity. Mechanical properties increased with more amounts of CCFCM due to bridging actions of high-aspect-ratio elements and reached similar or higher flexural strength than the control at 1 and 2 vol%. CCFCM had similar or higher mechanical properties than POLY-0.5, except the synthetic fibers increased the flexural toughness index by 85% compared to the maximum 53% increase by CCFCM. The most significant enhancement was with CCFCM-1 and 2 vol% in rapid freeze–thaw cycling and deicer chemical application evaluation. CCFCM-2 maintained 95% of its original mass and 77% of the initial dynamic modulus after more than 200 cycles. The incorporation of CCFCM as a replacement of natural aggregate shows a high potential for previous concrete while creating a new use for this high-volume waste from the automobile and aerospace industries for a circular economy.

Concrete material for greening

Abstract: A concrete material for greening, which comprises a concrete material having cement and an aggregate compounded therein and, added thereto as a granular filler or a powdery additive, a silica based mineral being excellent in water absorbing property, water holding property and the like. Silica based minerals include diatomaceous earth, pearlite and other minerals containing a major amount of silica. As the aggregate, an ordinary aggregate such as crushed stones or ballast can be used. The aggregate may be used together with the above silica based filler. A light, porous concrete material can be produced by using only lightweight aggregates such as diatomaceous earth and pearlite. One or more of fibrous materials prepared by crushing bamboo, coconuts and wood material and the like and plant fiber materials such as those from Peat Moss can be added as water holding aids for supplementing the water holding property of concrete.

Summary of a Computer Modeling Study to Understand the Performance Properties of Fully Permeable Pavements

Abstract: This technical memorandum summarizes the computer modeling of the expected pavement performance of fully permeable pavements using laboratory test results described in an earlier report, and development of pavement designs for critical distresses. Full-factorial experimental designs were followed, taking pavement type, material type, pavement geometry (thicknesses, and slab dimensions for concrete pavement only), climate, truck axle type, traffic load, and traffic speed (hot mix asphalt [HMA] only) into consideration. This resulted in almost 20,000 analysis cases using layer elastic theory for HMA and finite element analysis for concrete. The results indicate that sufficient structural strength can be obtained with appropriate and reasonable pavement designs for fully permeable concrete and hot mix asphalt pavements.

Quantifying the Non-Linear Hydraulic Behavior of Pervious Concrete

Abstract: Results are presented for the intrinsic permeability and form drag coefficient (CF) for a set of nominally identical cylindrical pervious concrete specimens. Specimens were tested at a range of flow rates in a constant head permeameter. The mean and standard deviation of the permeability and CF show substantial variability. This statistical characterization of hydraulic performance was used to model the behavior that would be observed using other standard methods for characterizing hydraulic performance of porous pavement mixtures. Results indicate that falling head, constant head, and infiltration tests have the potential to significantly underestimate the permeability of porous pavement mixtures. Results from modeled falling head tests showed that this test results in permeability estimates up to a factor of ten lower than the actual permeability and are uncorrelated to the actual permeability. For high permeability pavement mixtures, falling head tests will only provide adequate values of permeability if run at heads so low that measurement resolution is a problem. Constant head tests can be used, though model results indicate that, even for very small hydraulic gradients, the head versus flow rate relationship is quadratic. As such, CF must be calculated. Failure to do so leads to significant underestimation of the permeability. For most applications, the permeability of a well-designed and placed pervious concrete is more than adequate and the improvement in accuracy gained by fully characterizing both the permeability and CF of a pavement is not necessary. However, for poorly constructed pavements, or pavements that need to infiltrate large amounts of run-on from adjacent impervious areas, the additional accuracy may be important. The additional level of accuracy is also important for research into improving design and construction of pervious concrete where comprehensive and accurate characterization of test specimens is needed for statistically significant comparisons between different design specimens.