Penetration and Strength Analysis of Pervious Concrete

Porous concrete is an amalgamation of coarse aggregate, Portland cement, and water, which permits rainfall water to permeate through the surface and into the ground before it runs off. Porous concrete encompasses little or no fine aggregates and adequate cementitious fixative to coat the coarse aggregate while keeping the voids interconnected. IRC 44-2017 states that range of permeability for pervious concrete should be from 0.135 cm/second to 1.22 cm/second and array of compressive strength should be 5MPa - 25MPa. In this experimental study, two properties of no fine concrete namely compressive strength and porousness at the curing age of 7th & 28rd days has been targeted. Compressive strength and Infiltration tests were conducted on the pervious concrete of grade M10 and M15 by keeping variation of fine aggregates of 0% - 5%. We observed that fines aggregate help to rise the compressive strength of porous concrete but decrease the permeability. Thus, by careful optimization of the mix, pervious concrete can be obtained for suitable use in low strength load.

Karakteristik Infiltrasi dan Potensi Irigasi di Lahan Kering Kecamatan Bayan Kabupaten Lombok Utara

Agricultural development with horticultural crops on dry land is one of the government's efforts to increase dry land productivity so that new paddy fields are created in the Bayan area. Noting that land infiltration capability and its classification are important factors needed in irrigation planning to support the development of horticultural agriculture, so it is necessary to conduct field research on this matter. This study aims to determine the characteristics and classification of land infiltration and determine the trend of irrigation that can be applied. Field infiltration tests were carried out in Anyar and Sukadana villages with 4 test points each. The infiltration rate test in the field was carried out using a double ring infiltrometer and a soil test at the Geotechnical Laboratory, Faculty of Engineering, Unram. Analysis of the data used Horton's formula as a comparison and the results of the analysis were presented in the form of tables and graphs, conclusions were made descriptively. The results showed that the average infiltration rate in Anyar Village was at point 1 = 26.90 cm/hour, point 2 = 14.94 cm/hour, point 3 = 27.33 cm/hour, and point 4 = 8.21 cm/hour with soil including sandy clay. Infiltration rate classification of points 1 and 3 is very fast, point 2 is fast and location 4 is rather fast. For Sukadana Village the infiltration rate was obtained at point 1 = 43.52 cm/hour, point 2 = 36.67 cm/hour, point 3 = 12.86 cm/hour, and point 4 = 10.97 cm/hour, with the condition sandy clay soil. Sukadana's infiltration rate classification points 1 and 2 are very fast and points 3 and 4 are rather fast. Based on the results of the infiltration test, for very fast and fast infiltration, it is potential to apply jet irrigation such as sprinklers or perforations and for rather fast infiltration, drip irrigation can be applied with limited drip system

Physical Evolution of Solutions in Response to the Contact of Water with Beans: Case Study of Soaking and Boiling

The present paper aims to highlight the physical evolution of solutions from soaking and beans cooking process. This is motivated by the desire to shed light on the particular behavior of the bean end-of-cooking solutions when they are incorporated into the soil. For that purpose, solutions from soaking were produced by putting in contact 2kg of sorted and quickly washed beans seed with 8kg of water with known physical characteristics. Concerning the solutions from cooked beans, they were produced by putting on fire the pot containing the mixture of the water from soaking and bean seeds. The beans were a variety of Phaseolus vulgaris L.,known as “Meringue”. The cooking process was done without salts. The samples of solutions were collected as follow: 30 and 60 minutes respectively after the beginning of the soaking, 30, 60, and 90 minutes after the beginning of the cooking process of the beans soaked during 60 minutes. After each sampling, the equal volume of the solution collected was replaced with the water used for the cooking process. The color of the water used for the cooking process is translucent. Concerning solutions from soaking, their coloration are gradually reddish. Solutions from soaking and cooking process became abruptly dark red. From 60 minutes of the cooking process after soaking, the dark red coloration turn to strong brown. The solution handled in the case of the present study, from soaking and cooking the beans are gradually enriched in flakes compared to the situation noticed in the water used for the cooking process. But, the enrichment becomes abruptly high with the beginning of the cooking process after the process of soaking. In terms of consequence, their physical parameters studied in the present case study all increase in the same manner, notably the mass, the volumetric mass, and the density of the different solutions. The infiltration tests made including the water used for the different processes, solutions form the end of cooking the beans, and human urine show that the infiltration rate of the water from cooked beans is very low compared to that of the water used for the processes and human urine. The total infiltration of solution of the end of cooking the bean reveals on the infiltration surface the presence of a film of a matter bearing molds, generated by the progressive settling of this solution. The correlations established between the different parameters followed up here are highly positive. But in detail, the influence of an under laid parameter, known here as temperature, has been identified as being the responsible of the questioned behavior of the parameters taken in pairs in the case of correlation studies made. Finally, from this work, it emerges that the specific behavior of the bean end-of-cooking solution when it is introduced into the soil is justified by its progressive enrichment in organic matter during the cooking process.

Wildfire impact on the hydrological conditions of an Alpine slope

<p>Wildfire events have severe effects over mountain environments, changing dramatically the local terrain hydrogeological conditions and frequently affecting slope stability. Besides burning vegetation, wildfires induce a modification on soil properties that could result in a decreased capacity of infiltration. This leads to an increase of erosion and, potentially, of the related geohazards, such as flash flooding and debris flows, in the vicinity of the affected sites.</p><p>Past studies found that this reduced infiltration rate changes over time and the original hydrogeological soil properties are expected to recover in as long as 10 years after the wildfire event, depending on the environmental characteristics and on the soil properties of the site.</p><p>Our work aims to investigate the impact of a wildfire on the infiltration conditions of a slope located in the Southern Alps, considering as a case study a wildfire event occurred in Sorico (CO) in December 2018.</p><p>The effects of the wildfire on the infiltration rates and the subsequent recovery of the original hydrogeological properties were evaluated over the span of more than two years after the event. Infiltration tests were performed both within the most affected area as well as in the nearest unburnt area. Results were then correlated with precipitation and satellite imagery data in order to retrieve a recovery factor, necessary for the calibration of a simple 1D hydrogeological model.</p>

Modelling uniform and preferential flow in bioretention systems

<p>Bioretention systems are increasingly used worldwide to mitigate the impacts of urban stormwater runoff on the water cycle. The proper management of bioretention systems requires accurate modeling of physical processes occurring within these systems. This study developed and tested a generic and physically-based model called Infiltron-mod. This model makes use of the Darcian approach (assuming Mualem-van Genuchten model for the description of the soil hydraulic properties) and mass conservation. The first version of the model considers evapotranspiration, overflow, exfiltration to surrounding soils, along with the filter hydraulic head and underdrain discharge. The proposed model was tested against field data from a monitored bioretention basin in Melbourne, Australia. We used two rainfall events to calibrate the model and 20 rainfall events for its validation. We achieved quite nice fits of experimental data with median NSE values in the order of 0.7-0.75 for the outflow rates. Despite good performance for outflow rates, we noticed the potential for improvement for the simulation of the height of water in the systems. Such discrepancy is probably the result of preferential flows.</p><p>As a second step, we developed a specific module to implement the dual permeability approach to model preferential flow. Such an approach may simulate the concomitancy of matrix flow in part of the system and rapid preferential infiltration into macropores. The new module Infiltron-mod-pref was implemented and investigated. Prior to its use for field data, we validated the new module against more straightforward water infiltration experiments. Several large ring infiltration tests were performed on a field dedicated to infiltrating stormwater, and the two versions of the proposed model, Infiltron-mod and Infiltron-mod-Pref. We clearly showed the benefit to account for the preferential flow in the model. The next step will be the use of Infiltron-mod_Pref for field data from the monitored bioretention basin in Melbourne.</p><p>The proposed approach then seems a useful first step to assess both performance and impact of bioretention basins for catchment-scale flow regime management and has real potential for application where user-friendly and simple model calibration and deployment are desired.</p>

Post-fire soil water repellency, sorptivity, and the measurement of infiltration

<p>Wildfires are frequently associated with the increased potential for runoff, flooding and debris flows during and after subsequent rainfall events. Specifically, wildfires can cause soils to become water repellent, which is believed to slow, if not halt, the infiltration of water into the soil. However, there exists no mechanistic way to determine the effect of post-wildfire water repellency on infiltration and runoff—until now. We have recently developed a simple physically-based model to account for the effect of water repellency on the soil hydraulic property of sorptivity. Further, since sorptivity is crucial to understanding the relationship between water repellency and post-fire infiltration, there is a need for a robust and accurate method to measure sorptivity in the field. All research was conducted in the laboratory using a fine silica sand, some of which was treated with Scotchgard<sup>TM</sup> to induce water repellency. Treated and untreated sand was mixed proportionally by weight to create various degrees of water repellent sand. Upward infiltration tests (wicking experiments) were used to validate the sorptivity model. Then, two common field methods (a 1D infiltrometer ring and a 3D tension infiltrometer) were used to measure downward infiltration and extract sorptivity data. Results showed that we able to predict sorptivity given the degree of water repellency and basic soil properties, that sorptivity measured using common field methods reflected the degree of water repellency, and that both downward infiltration measurement methods yielded similar sorptivity values.</p>

Influence of the filter properties in the diffusive transport of ions through a bentonite. Sensitivity analysis

<p>The deep geological repository concept for spent nuclear fuel considers many safety elements. Among them, compacted bentonite has been selected as the primary engineering barrier between the encapsulated radioactive waste and the host rock. Thermo-hydro-mechanical behaviour of this material has been studied in detail from an experimental and numerical point of view. Furthermore, the study of chemical behaviour has become very important, both for the evaluation of the transport of species through the clay matrix and for the evaluation of their coupling to other physico-chemical phenomena.</p><p>Generally, to conduct these types of studies, infiltration tests through compacted bentonite columns are carried out using an experimental setup composed of common parts: (i) porewater and infiltration water reservoirs, (ii) pumping devices and (iii) a confined sample of bentonite. The infiltration/output solutions are injected/extracted through filters positioned in the top/bottom of the sample. The results obtained in these tests are strongly influenced by the properties of these filters. For this reason, it is very important how the chemical species and the fluid are transported in the filters to correctly interpret the experimental observations. The study presented in this work is framed in this context, in which a numerical sensitivity analysis of the transport properties and size of the filters has been conducted. For this purpose, a reactive transport model for bentonites (assuming this material as a double porosity media) formulated by the authors and fully implemented in the multiphysics platform, COMSOL, has been used to simulate a cation exchange-infiltration test in MX-80 bentonite defined in the “Chemical session” of the Task Force on Engineered Barrier Systems (EBS) organised by SKB AB. The results obtained depend on the tortuosity, porosity and thickness of the filters. These parameters have been estimated for the correct interpretation of the selected test.</p>

Geophysical Characterization of Hydraulic Properties around a Managed Aquifer Recharge System over the Llobregat River Alluvial Aquifer (Barcelona Metropolitan Area)

Managed aquifer recharge using surface or regenerated water plays an important role in the Barcelona Metropolitan Area in increasing storage volume to help operators cope with the runoff variability and unexpected changes in surface water quality that are aggravated by climate change. The specific aim of the research was to develop a non-invasive methodology to improve the planning and design of surface-type artificial recharge infrastructures. To this end, we propose an approach combining direct and indirect exploration techniques such as electrical resistivity tomography (ERT), frequency domain electromagnetics and data from double-ring infiltration tests, trial pits, research boreholes and piezometers. The ERT method has provided much more complete and representative information in a zone where the recharge project works below design infiltration rates. The geometry of the hydrogeological units and the aquifer-aquiclude contact are accurately defined through the models derived from the interpretation of ERT cross-sections in the alluvial aquifer setting. Consequently, prior to the construction of recharge basins, it is highly recommended to conduct the proposed approach in order to identify the highest permeability areas, which are, therefore, the most suitable for aquifer artificial recharge.

Detailed Geophysical Mapping and Hydrogeological Characterisation of the Subsurface for Optimal Placement of Infiltration-Based Sustainable Urban Drainage Systems

The continuous growth of cities in combination with future climate changes present urban planners with significant challenges, as traditional urban sewer systems are typically designed for the present climate. An easy and economically feasible way to mitigate this is to introduce a Sustainable Urban Drainage System (SUDS) in the urban area. However, the lack of knowledge about the geological and hydrogeological setting hampers the use of SUDS. In this study, 1315 ha of high-density electromagnetic (DUALEM-421S) data, detailed lithological soil descriptions of 614 boreholes, 153 infiltration tests and 250 in situ vane tests from 32 different sites in the Central Denmark Region were utilised to find quantitative and qualitative regional relationships between the resistivity and the lithology, the percolation rates and the undrained shear strength of cohesive soils at a depth of 1 meter below ground surface (m bgs). The qualitative tests enable a translation from resistivity to lithology as well as a translation from lithology to percolation rates with moderate to high certainty. The regional cut-off value separating sand-dominated deposits from clay-dominated deposits is found to be between 80 to 100 Ωm. The regional median percolation rates for sand and clay till is found to be 9.9 × 10−5 m/s and 2.6 × 10−5 m/s, respectively. The quantitative results derived from a simple linear regression analysis of resistivity and percolation rates and resistivity and undrained shear strength of cohesive soils are found to have a very weak relationship on a regional scale implying that in reality no meaningful relationships can be established. The regional qualitative results have been tested on a case study area. The case study illustrates that site-specific investigations are necessary when using geophysical mapping to directly estimate lithology, percolation rates and undrained shear strength of cohesive soils due to the differences in soil properties and the surrounding environment from site to site. This study further illustrates that geophysical mapping in combination with lithological descriptions, infiltration tests and groundwater levels yield the basis for the construction of detailed planning maps showing the most suitable locations for infiltration. These maps provide valuable information for city planners about which areas may preclude the establishment of infiltration-based SUDS.