Showing papers on "Pervious concrete published in 2022"

Life-cycle assessment and multi-criteria performance evaluation of pervious concrete pavement with fly ash

Abstract: Pervious concrete pavement has great potential in reducing surface water runoff and improving water quality. This study aims to conduct life cycle assessment (LCA) and multi-criteria assessment of pervious concrete pavement with the use of fly ash. The research significance lies in the integration of hydraulic and structure designs for developing functional unit of pervious concrete pavement and combining environmental impacts with engineering and economic indicators. A full LCA of pervious concrete pavement system was conducted including the stages of material, construction, transportation, use, maintenance, and end-of-life stage. The impact assessment included global warming potential, energy consumption, and eutrophication potential due to runoff purification. The pervious concrete pavement structures were designed based on mechanical properties of mixtures, hydrological requirement of reservoir layer, and subgrade soil type to meet equivalent performance on parking lot and highway shoulder. Multi-criteria analysis of pervious concrete mixes and pavement systems were presented based on the normalization of environmental impacts, engineering performances, and economic costs. The LCA results showed that the environmental impacts of pervious pavement system were mainly generated from material stage in terms of 81% to 92% GHG emissions and 70% to 83% energy consumption. The performance rankings of pervious concrete mixes were different from those of pervious pavement structures. The pervious concrete pavement with fly ash can cause greater or less environmental impact, depending on mechanic properties of pervious concrete and the required surface layer thickness to achieve equivalent structural performance.

Life-cycle assessment and multi-criteria performance evaluation of pervious concrete pavement with fly ash

Abstract: Pervious concrete pavement has great potential in reducing surface water runoff and improving water quality. This study aims to conduct life cycle assessment (LCA) and multi-criteria assessment of pervious concrete pavement with the use of fly ash. The research significance lies in the integration of hydraulic and structure designs for developing functional unit of pervious concrete pavement and combining environmental impacts with engineering and economic indicators. A full LCA of pervious concrete pavement system was conducted including the stages of material, construction, transportation, use, maintenance, and end-of-life stage. The impact assessment included global warming potential, energy consumption, and eutrophication potential due to runoff purification. The pervious concrete pavement structures were designed based on mechanical properties of mixtures, hydrological requirement of reservoir layer, and subgrade soil type to meet equivalent performance on parking lot and highway shoulder. Multi-criteria analysis of pervious concrete mixes and pavement systems were presented based on the normalization of environmental impacts, engineering performances, and economic costs. The LCA results showed that the environmental impacts of pervious pavement system were mainly generated from material stage in terms of 81% to 92% GHG emissions and 70% to 83% energy consumption. The performance rankings of pervious concrete mixes were different from those of pervious pavement structures. The pervious concrete pavement with fly ash can cause greater or less environmental impact, depending on mechanic properties of pervious concrete and the required surface layer thickness to achieve equivalent structural performance.

Engineering properties and lifecycle impacts of Pervious All-Road All-weather Multilayered pavement

Abstract: • Developed Pervious All-Road All-weather Multilayered pavement (PARAMpave). • Addressed the concern of inherent low strength of pervious concrete via PARAMpave. • Quantified the reduced environmental impacts of PARAMpave over concrete blocks. • PARAMpave were found to be economical alternatives to conventional paver blocks. Conversion of pervious natural ground into impermeable pavement systems has caused severe environmental impacts such as urban heat islands, increased infrastructure-related greenhouse gas (GHG) emissions and energy consumption, and runoff generation / flashfloods during rainfall events. These phenomena can be addressed with the use of pervious concrete pavement (PCP) systems, which have gained acceptance as sustainable alternatives to conventional materials. However, implementation of PCP technology is limited to low-volume roads, sidewalks, and parking lots attributed to low strength and the need for high quality control during construction compared to traditional pavements along with limited understanding on the end-of-life significance due to the green PCP product. Therefore, the major objective of this research was to develop a pavement system with superior structural and hydrological performance characteristics over traditional PCP, while also quantifying the energy consumed, amount of GHG produced, and costs associated with its design and construction. Thus, a Pervious All-Road All-weather Multilayered pavement (PARAMpave) was conceptualized and designed that comprised a 300 mm square paver block created with a 60 mm lower structural layer overlaid with a 30 mm water-draining surface wearing course pervious concrete layer. The major properties of PARAMpave products included porosity ranging from 17% to 24%, permeability varying from 0.77 cm/s to 1.33 cm/s, and flexural strength between 4.83 MPa and 6.13 MPa, indicating their improved structural and hydrological performance compared to traditional designs. Further, a cradle-to-gate lifecycle approach was utilized to perform a comparative evaluation between PARAMpave and Portland cement concrete (PCC) paver blocks. The PARAMpave products consumed lower energy (8.22% to 8.51%) and emitted lower GHGs (8.23% to 8.43%) compared to PCC blocks of similar dimensions. Additionally, PARAMpave blocks were about 10% cheaper and almost 10% lighter than a PCC paver block. The reduction in GHG emissions, energy consumption, and capital costs indicate that PARAMpave blocks are a sustainable class of roadway products. Also, the strength and permeability magnitudes of PARAMpave indicate that they have high potential for applications in different road classes and diversified weather conditions.

Multi-aspect engineering properties and sustainability impacts of geopolymer pervious concrete

Abstract: This study aimed to comprehensively evaluate multi-aspect engineering properties and sustainability impacts of geopolymer pervious concrete. Geopolymer binder was prepared using metakaolin (MK) or fly ash (FA) with granulated blast furnace steel slag (GBFS) and used to fabricate pervious concrete; while conventional pervious concrete was made with Portland cement (PC). The strength and durability results show that the MK based pervious concrete exhibited superior performance in mechanical property (3200 psi compressive and 520 psi splitting tensile strength) and lowest mass loss (3%) after 70 cycles of freeze & thaw test. The FA based pervious concrete had about 10% higher splitting tensile strength and better raveling resistance than the PC based pervious concrete, but its freeze & thaw resistance was the lowest (8% mass loss after freeze & thaw test). The hydraulic conductivity test results show that the porosity was the major influence factor for permeability coefficient. The permeability coefficients increased from 3.5 to 12 mm/s with the increase of porosity from 13.5% to 24.5%. However, the binder type had no obvious effect on the permeability and clogging resistance. In addition, life-cycle assessment (LCA) was applied to quantify energy consumption and greenhouse gas (GHG) emission of pervious concrete with different raw materials. The FA based pervious concrete showed the lowest energy consumption, while the MK based pervious concrete had slightly greater energy consumption than conventional pervious concrete. Compared with PC based one, the GHG emissions of MK and FA based pervious concrete could be reduced by 33% and 53%, respectively.

Stochastic lattice discrete particle modeling of fracture in pervious concrete

Abstract: This article presents a stochastic modeling approach for simulating the mechanical behavior of pervious concrete, based on novel extensions of the lattice discrete particle model. Selected digital images of the internal mesostructure, obtained from physical specimens, are used to survey material features and produce statistically representative descriptions of the pore networks. A procedure for estimating the statistical features of the mesostructure is proposed, and samples of a spatially correlated random field are utilized to numerically reproduce the distribution of the large, connected pores in the material. The numerical samples are linked to the topology of the lattice network by means of two novel techniques proposed herein: (1) a random placement procedure for the poly‐sized spheres representing coarse aggregate and (2) a ray tracing technique, which is used to evaluate the effective distributions of mass, stiffness, and strength of each lattice element according to the local distribution of porosity. Numerical results demonstrate how the proposed model is capable of simulating both the large scatter in strength and the variety of failure modes that are observed when testing physical specimens of pervious concrete. The proposed procedure is generally applicable to different types of materials with varying porosity, opening up new possibilities for the simulation of porous media by means of lattice discrete particle modeling techniques.

Comparative study of fly ash and rice husk ash as cement replacement in pervious concrete: mechanical characteristics and sustainability analysis

Abstract: Pervious concrete is a special type of concrete consisting of cement, coarse aggregate and water. Cement is a widely used raw material for construction including pervious concrete and had led to the release of huge amounts of CO2 to the environment. Therefore, there is lot of research interest in finding supplementary cementitious materials. The present study examined and compared the feasibility of using industrial waste fly ash (FA) and agricultural waste rice husk ash (RHA) for sustainable pervious concrete production. An experimental program was performed with substitution of FA and RHA contents of 5%, 10%, 15% and 20% as cement replacement and water to binder ratio of 0.3, 0.35, 0.4 and 0.45. The characteristics of pervious concrete and sustainability analysis were compared for both FA and RHA replacement with control concrete mortar. The results showed that both FA and RHA have a negative effect on permeability. The compressive strength was optimum for FA content lies between 10% and 15% replacement level and RHA content of 5% replacement level. Furthermore, the utilisation of FA and RHA decreased production cost, the total embodied energy and carbon emission, resulting in cost-effective and eco-friendly pervious concrete.

Fly Ash-Added, Seawater-Mixed Pervious Concrete: Compressive Strength, Permeability, and Phosphorus Removal

Abstract: A mix proportion of off-spec fly ash (FA)-added, seawater-mixed pervious concrete (SMPC) was optimized for compressive strength and permeability and then the optimized SMPC was tested for the rate and extent of aqueous phosphorus removal. An optimum mix proportion was obtained to attain the percentages (% wt.) of FA-to-binder at 15.0%, nano SiO2 (NS)-to-FA at 3.0%, liquid-to-binder at 0.338, and water reducer-to-binder at 0.18% from which a 7-day compressive strength of 14.0 MPa and a permeability of 5.5 mm/s were predicted. A long-term maximum compressive strength was measured to be ~16 MPa for both the optimized SMPC and the control ordinary pervious concrete (Control PC). The phosphorus removal was favorable for both the optimized SMPC and the Control PC based on the dimensionless Freundlich parameter (1/n). Both the optimized SMPC and Control PC had a first-order phosphorus removal constant of ~0.03 h−1. The optimized SMPC had a slightly lower capacity of phosphorus removal than the Control PC based on the Freundlich constant, Kf (mg1−1/n kg−1 L1/n): 15.72 for the optimized SMPC vs. 16.63 for Control. This study demonstrates a cleaner production and application of off-spec FA-added, seawater-mixed pervious concrete to simultaneously attain water, waste, and concrete sustainability.

Influence of aggregate gradation and compaction on compressive strength and porosity characteristics of pervious concrete

Abstract: This study examined the influence of aggregate gradation on compressive strength and porosity in Pervious Concrete (PC) subjected to various compaction efforts. Two aggregate gradations 12–18 and 18–25 mm were recombined in different proportions in the range of 10–50% to obtain five different gradations. PC specimens were cast with these five aggregate gradations by applying standard Proctor compaction, varying efforts from 0 to 75 blows. Test results indicated that wet density and compressive strength increased with compaction effort at higher rate for specimens casted with Aggregate-to-Cement (A/C) ratio 2.5 than 5.0, but porosity reduced at almost the same rate for both A/C ratios. Compressive strength reduced when aggregate gradation with larger size particles increased, however porosity increased. Altering aggregate gradation or compaction effort yielded no significant change in PC properties for A/C ratio of 5.0 than it did for 2.5. The developed mathematical models predicted compressive strength and porosity of PC mixes in terms of aggregate gradation and compaction effort. The highest mean deviation and relative error of model prediction were 1.377 MPa and 10.4% for compressive strength, and 1.414% and 5.8% for porosity, respectively.