Porous Concrete Research Articles

Mechanical strength and hydraulic properties of modified porous concrete mixtures

This study presents a comprehensive experimental investigation on the behavior of porous concrete mixtures intended to be used as surface road layer containing mineral admixture. Silica fume and/or fly ash were used to formulate modified concrete mixes at ratios ranged from 10% to 20%. A systematic change in 50% of the 9.5 mm aggregate particles size was adopted throughout single size coarse aggregate of 5mm. This in turn produces two groups of concrete mixes and eight individual mixtures. The compressive and tensile strengths, voids content and permeability characteristics were measured and the obtained results were compared with relevant guide of porous concrete. The results showed that a moderate strength of 24 MPa can be obtained at early ages. For the same concrete mixture, the values of voids content and permeability were 21.7% and 19.3 mm/s, respectively. Such kind of concrete can be used in construction of roads and it helps in water draining purposes.

Proposal of numerical models to predict the diffuse field sound absorption of finite sized porous materials – BEM and FEM approaches

The prediction of the sound absorption coefficient in diffuse field conditions is of great interest to an acoustic project. Foams and granular materials like porous concrete have been used in many internal or external applications as sound absorbers. However, many doubts have regularly been discussed in scientific literature. The simple use of experimental impedance tube methods, that consider only the incident acoustic plane waves, is not equivalent to the experimental measurement in a reverberant room, which is necessary for a correct characterization of a given constructive solution. The scientific community has explored several methods to predict and approximate the sound absorption coefficient in diffuse field conditions, using only acoustic plane wave data. However, many of them do not allow a realistic approximation of the reverberant room measured data. Therefore, two numerical models are herein proposed which consider the porous media on the fluid-equivalent theory, first, a two-dimensional (2D) finite element method, and, second, a three-dimensional (3D) boundary element method (BEM). These methods are compared with analytical equations and experimental data from the reverberant room, studying the influence of the porous material panel size in the sound absorption coefficient in diffuse field conditions. To illustrate the proposed method’s practical interest, the BEM 3D model was used to determine the diffuse field’s sound absorption coefficient for finite-sized panels of porous concrete. This test was done for plane panels and for slit-like surfaces to highlight the possibilities of the proposed method.

Experimental Study on Water Percolating Concrete

This paper addresses two aspects namely a new method for manufacturing of percolating concrete blocks using different proportions of concrete mixture such as Portland cement, Coarse aggregates, fine aggregates, limestone, and water have been designed. Apart from this an attempt has also been made by adding small quantities of additives such as fly ash, rice husk ash etc. for its strength and suitability on par with the normal Concrete blocks. Another is a partial replacement of cement with supplementary cementation materials such as fly ash and metakaolin in different proportions for reducing high grade cement consumptions been proposed. The design of a Pervious Concrete is made in such a way that it allows the entire surface run off water to percolate down without retaining any drop/quantity in it. Thus, it is named as water percolating Pervious Concrete/ porous concrete. An alternative for reducing cement usage in concrete makes concrete eco-friendly. Thus, there comes an idea of partially replacing cement with supplementary cementations materials, The concern has been growing in recent years towards reducing the pollutants in water conservation and the environment. The continual urbanization has led to the increase in impervious surface area of the cities, further leading to blockage in percolation of precipitation from rainfall. This result is excess surface run off. To counteract this, pervious concrete is the solution. Hence, the pervious concrete having 15% to 35% interconnected pores by volume, allows direct infiltration of water through its structure. Since the strength of this block for highway suitability of roads is not yet tested. The main aim of this paper is to improve the strength characteristics of porous concrete. However, on comparison, with the published data it is suitable for foot paths/ pathways and parking lots and as driveways in the residential and small rural areas where less vehicular traffic. This will help in reducing the risk of water clogging and recharges the nearby ground water level. The Maintenance of the slab is also minimum and can be repaired and cleaned easily. Thus, it is worthy and useful in many ways

Developing Porous Concrete Interlocking Pavement Blocks Utilizing Recycled Concrete Aggregate for Rainfall Harvesting Use

Rainwater harvesting and flood prevention in cities are significant urban hydrological concerns. The use of porous pavement is one of the most effective solutions to handle this matter. Thus, this study aims to develop Porous Interlocking Concrete Pavement (PICP) using recycled aggregate from concrete waste. This porous pavement, then later, can be utilized in low traffic areas and parking lots to harvest water by infiltration and reduce surface runoff. First, the physical properties of the porous concrete blocks, such as density (unit weight), absorption, coefficient of permeability, and porosity, were studied. Also, the mechanical properties of concrete mixtures like compressive strength and flexural strength were tested. This study used two types of PICP, the first one with ordinary coarse aggregate (P1) and the second with recycled crushed concrete coarse aggregate (P2), and then compared their performance to the conventional concrete pavement blocks used the two types of coarse aggregate (R1 and R2). The results show that the unit weight (density) of porous types was reduced by 25% and 26%, and the total porosity increases by around 2.4 times and 18 times respectively, as compared to conventional concrete pavement types. However, the compressive strength and flexural strength of porous concrete types decreased by (55% and 71%), respectively, compared to conventional types. Overall, the infiltration test results showed that the infiltrated water through porous concrete increased by about 83% in comparison to conventional concrete. From the results, utilizing porous concrete pavement can be considered a promising material in terms of water harvesting and decreasing rainwater flooding. Additionally, using recycled concrete can bring economical and environmental benefits.

Research studies on composition of porous concrete on the sidewalk

In infrastructure development, technology is needed that is powerful, effective, efficient in implementation time, efficient, and environmentally friendly. Porous concrete has a cavity that can flow water directly into the ground so that it can overcome the problem of water absorption. Porous concrete can be utilized in the pavement with light traffic loads such as the sidewalk. However, because porous concrete only consists of a mixture of cement, water, and coarse aggregate, porous concrete has a low compressive strength. The research is needed on the composition of porous concrete to be used on the sidewalk. Research using the ACI-522R-10 method with a variation of the ratio of cement and coarse aggregate is 1: 3, 1: 4, 1: 5, 1: 6 and cement water factor 0,30. The test results obtained the highest average compressive strength value of 16.027 MPa with an increase of 45.30% compared with no additives, as well as being in the classification of concrete brick of C quality which is suitable for the sidewalk. The results showed that an increase in the average compressive strength value along with a reduction in the amount of coarse aggregate was obtained both under conditions and with the addition of additives.

Application of porous concrete to resolveflood on the roads

In the rainy season, many cases of roads being submerged in water because of a lack of drainage capacity and low water absorption by the subgrade. This study utilizes porous pavement as an interlocking pavement to increase water absorption to the drainage layer and subgrade. Porous concrete is made from cement mixture : coarse aggregate = 1:6 with w/c ratio 0,4. The results showed the value of specific gravity, water absorption, compressive strength, and Na2SO4 resistance respectively 1.703 gr/cm3, 2.57%, 10.8 MPa, and 0.79%. To see the level of serviceability, no fine interlocking pavement is arranged above the drainage layer and the levelling layer, and then a trajectory and inundation test is performed. The result of inundation and track tests shows that the construction can pass water to subgrade without inundation and can withstand the wheel loader that is equivalent to 13000 kg so that it can be used for sidewalks, park lanes, and pavement with a maximum axle load of 8 tons.

Investigating properties of pervious concretes containing coconut shell flake and ash

Pervious concrete or non-fine concrete is a simple form of lightweight concrete made by eliminating the use of fine aggregates. As a result of not using a fine aggregate in pervious concrete, then created a cavity filled with air and water can be passed. This cavity resulted in a reduced density of the concrete and the reduced amount of area that needs to be covered by a cement paste, thereby reducing the compressive strength. This study aimed to utilize waste material to increase the compressive strength of pervious concrete. The waste material was the coconut shell ash and coconut shell flake. The method was to strengthen the coarse aggregate concrete mixture. It was expected to increase the compressive strength along with the increase in permeability. Thus, in this study, the researchers will replace part of the coarse aggregate with coconut shell flake with percentage 0%, 2,5%, 5%, 7,5%, 10% and partially replace cement with coconut shell ash with percentage 0%, 2,5%, 5%, 7,5%. The results show that the combination of coconut shell flake and coconut shell ash does not increase the compressive strength of the concrete mixture. However, it increases the porosity, permeability, and as a result, the density is getting lower. Further study will be performed on porous concrete using coconut shell flake for lower load facilities, such as pedestrian or bicycle pathways.

The Prospect of Microwave Heating: Towards a Faster and Deeper Crack Healing in Asphalt Pavement

Microwave heating has been shown to be an effective method of heating asphalt concrete and in turn healing the damage. As such, microwave heating holds great potential in rapid (1–3 min) and effective damage healing, resulting in improvement in the service life, safety, and sustainability of asphalt pavement. This study focused on the microwave healing effect on porous asphalt concrete. Steel wool fibres were incorporated into porous asphalt to improve the microwave heating efficiency, and the optimum microwave heating time was determined. Afterwards, the microwave healing efficiency was evaluated using a semi–circular bending and healing programme. The results show that the microwave healing effect is largely determined by the steel fibre content and the mix design of the porous asphalt concrete.. Besides, the uneven heating effect of microwave contributes to an unstable damage recovery in the asphalt mixture, which makes it less efficient than induction heating. However, microwaves exhibited the ability to penetrate further into the depth of the test specimen and heat beneath the surface, indicating deeper damage recovery prospects.

Influence of water repellent on the property of solid waste based sulfoaluminate cement paste and its application in lightweight porous concrete

• It is feasible to use water repellents reduce the water absorption of LPC based on SW-CSA cement. • The effect of water repellents on the properties of SW-CSA cement paste was presented. • Using calcium stearate as the water repellent doesn’t affect the hydration of SW-CSA cement. Solid waste-based calcium sulfoaluminate (SW-CSA) cement is a type of low carbon cement that uses solid waste as raw material. It is usually used to prepare lightweight porous concrete (LPC) due to its short setting time. However, high water absorption of LPC based on SW-CSA cement limits its extensive application. Water repellent can be mixed into binder material to reduce the water absorption of LPC, but it may affect the hydration properties of SW-CSA cement paste, which influences the performance of LPC correspondingly. Calcium stearate (CS), sodium oleate (SO) and sodium methyl siliconate (SMS) are three familiar commercial water repellents. To find the suitable internal mixing water repellent for LPC based on SW-CSA cement, the effects of three CS, SO and SMS on the water absorption, hydration, compressive strength, fluidity, and setting time of SW-CSA cement paste were explored. Besides, the properties of LPC with CS and SO added were also studied. The results indicated that using CS as the water repellent could reduce the 1 day water absorption of SW-CSA cement paste by 45.9% and the water absorption of LPC by 33.0%. It also reduced the setting time of SW-CSA cement paste and increased the final compressive strength of LPC, which was conducive to the preferred rapid setting and high compressive strength of LPC. The hydrophobicity of SW-CSA cement paste with SO was better than that of SW-CSA cement paste with CS. But using SO and SMS as the water repellent retarded the early hydration of SW-CSA cement and prolonged the setting time of SW-CSA cement and reduced the final compressive strength of SW-CSA cement paste. Therefore, SO and SMS can’t be used as the internal mixing water repellent of LPC based on SW-CSA cement, while CS is a promising internal mixing water repellent of SW-CSA cement to prepare LPC.

Utilization of post-consumer carpet calcium carbonate (PC4) from carpet recycling as a mineral resource in concrete

The short residence time of certain building materials, such as carpets, results in a notable waste stream that has the potential to be a resource for other material systems. In this work, we explore the utilization of post-consumer carpet calcium carbonate (PC4) consisting primarily of the material from carpet backing, which has thus far found few markets, as a potential mineral admixture in the production of concrete. The effects on mechanical and material properties are examined for concrete mixtures with PC4 used as 5 and 15% mass replacement of Portland cement, and PC4 used as 5 and 15% mass replacement of fine aggregates. The effects of PC4 on the slump, air content, unit weight, and setting times were assessed. Additionally, compressive strength, flexural strength, coefficient of thermal expansion, shrinkage, bulk density, void volume, and absorption were measured. Due to the known presence of antimony in PC4, leachate from cured specimens was examined. Additionally, greenhouse gas emissions to manufacture the mixtures were quantified. The results indicate that PC4 can increase air content in concrete by 3.5–10% and decrease the unit weight by up to 11% in fresh concrete. PC4 also led to a loss in compressive strength by up to 60%. Thus, the findings indicate that it is possible to form a less dense, more porous concrete by using PC4 as a mineral constituent in concrete, but with some loss in performance. Through appropriate selection of applications or through supplementary treatment of PC4, it may find a suitable market in the concrete industry.

Experimental Investigation on Enhancing the Strength of Porous Concrete by adding Polypropylene Fiber

Porous concrete has its application in many fields. Mainly for drainage purpose porous concrete can be used as a covering as well as to drain the liquid. Strength is only drawback in the porous concrete as the surface area contact between the coarse aggregates is less. In order to enhance the strength properties, poly propylene was used in layers. Various no of layers was introduced in the prism as well as for cube to determine the strength enhancement properties. Through experimental study it was found that strength due compressive force of the pervious concrete increases up to placing 3 layers of polypropylene geo textile fabric and get decreased after that. Similar to the compression test, the flexural strength also showed similar behaviour in the increase in strength up to the 3no of layers. Similarly, porosity test was carried to find the effect of porosity due to PP layers. It was found that 18.5% reduction in porosity was noted when 3 layers of PP were incorporated.

Sustainable Urban Pavement for Cities Affected by El Niño using Porous Concrete

The El Niño phenomenon is caused by the change in atmospheric pressures, which produce the accumulation of hot surface waters on the eastern flank of the Pacific Ocean; causing intense rainfall that runs over the surface affecting the urban drainage of the city due to the lack of a permeable pavement; porous concrete allows infiltration of surface water runoff through its pores. The present investigation evaluates porous concrete in the range of w/c relationships of 0.30 and 0.32; the results indicate that the compressive strength, flexural strength and permeability coefficient increase; and that the surface runoff, cost, water footprint and carbon footprint are lower than conventional concrete.

Studi Perbandingan Efisiensi Perbaikan Mutu Air Limbah Domestik melalui Filtrasi Horizontal dengan Beton Porous Recycled Aggregate Berlapis

Domestic wastewater pollution is one of the reasons for the decline in the national Water Quality Index. The increasing number of people with inadequate sanitation facilities requires a solution. Porous concrete with RCA aggregate has the potential to improve domestic wastewater. Made of porous concrete, the filter is made with dimensions of 40×40×5 cm3 using RCA aggregate with 0.5-2.0 cm gradation. Two reactor models of the same size were prepared, containing 3 and 4 layers of filters. Domestic wastewater as a test object comes from Tlogomas Integrated Sewer System, flowed continuously into the model. The results of Test 1 show that the 3-Filters Reactor Model can improve the pH and COD values according to the quality standard, while the 4-Filters Reactor Model can only improve the pH value. The results of Test 2 show that the 3-Filters Reactor Model can improve the pH and TSS values according to the quality standard, while the 4-Filters Reactor Model can only improve the pH value. The average efficiency of the filtration against influent shows that the 3-Filters Reactor Model is better than the 4-Filters Reactor Model with the percentage of improvement in pH 11.54%, BOD 26.15%, COD 20.79%, and TSS 46.37%. However, in sediment trapping, the 4-Filters Reactor Model is superior with 112 mm compared to the 3-Filters Reactor Model which is 100.5 mm.

Enhancing the strength characteristics of No-fine concrete using wastes and nano materials

No-fine concrete is a form of lightweight porous concrete, obtained by removing the sand from the normal concrete mix. The unique characteristic of high permeability of this material has mainly facilitated its applications such as in retaining walls and drainage covers for many decades. Other benefits of this form of concrete are also with low density, efficient thermal insulation and smaller drying shrinkage. Despite such benefits, its applications are limited in practice due to its smaller strength compared to convensional concrete. This study investigates the strength enhancement of No-fine concrete using waste material (i.e. coir fiber) and nano-graphene derivatives. A series of mechanical and hydraulic experiments was conducted to characterize the properties of modified No-fine concrete matrix and optimized dosages were identified to yield the expected behaviour as required by relevant standards. The mechanisms of new additives based No-fine concrete reactions were also unveiled using microscopic driven analytical techniques conducted on representative concrete specimens. Results revealed that the improved strength characteristics of No-fine concrete enhance its use as a wide application in Civil Engineering.

Study on Engineering Performance of Green Porous Sponge Ecological Concrete

To meet the needs of sponge city construction, based on the design method of mix proportion of green porous sponge ecological concrete, the engineering performance of green porous sponge ecological concrete was studied with orthogonal experimental. The results show that the compressive strength of the specimens peaked at the 0.9% admixture of sponge; based on the optimal admixture of sponge, the compressive strength of the specimens peaked at the 12% admixture of mineral powder; compared with the ordinary concrete, the water‐retaining property of green porous sponge ecological concrete is twice than ordinary, and green porous sponge ecological concrete has high permeability and low evaporation; under the same external temperature, the maximum temperature of concrete surface is lower than ordinary; and under three work conditions, the volumes of water going through the green porous sponge ecological concrete, respectively, are 1.78 kg/(s·m2), 1.47 kg/(s·m2), and 1.62 kg/(s·m2), and the value of second totally dry condition is minimum because of water blocking affection of the internal sponge. The research results will provide help for the infrastructure construction of sponge city and play an important guiding significance to promote the construction of resource‐saving and environment‐friendly cities.

Electrochemical analysis of corrosion process of steel bar in fluid simulating porous concrete

Electrochemical analysis of corrosion process of steel bar in fluid simulating porous concrete

STUDI KOMPARATIF KERUSAKAN BETON PADA STRUKTUR KOLOM YANG KEROPOS DENGAN METODE GROUTING

Concrete is a material widely used in construction projects. The quality of concrete is strongly influenced by some of its constituent materials such as water, cement, coarse aggregates, fine aggregates and other additives. In the implementation of construction using concrete, there is a great deal of damage to concrete materials, one of which is porous or with other names voids (cavities or holes). Therefore, repair methods used for occurring damage in concrete are needed. This study used a 15cmx15cmx15cm cube-shaped concrete sample divided into three samples, namely 6 cubes of normal concrete, 6 cubes of concrete made intentionally porous with grouting method using Sikagrout215, and concrete which was intentionally made porous with a method of grouting using a mixture of cement and water (cement paste) 6 cubes. Each cube were tested its compressive strength at the stage of 7, 21 and 28 days. The results showed that the cause of porous concrete was caused by several factors including cement water factor, lack of compaction process, the aggregate ratio used, and poor workability. Concrete compressive strength results at 28 days showed that the compressive strength of normal concrete was 230,459 kg / cm², concrete grouting with 215 cycles of 318,532 kg / cm², and grouting concrete with a mixture of cement and water 316,707 kg / cm². Grouting concrete using 215 cycles has the largest value among the three samples. Hence, in this study the grouting method is the right choice to make porous concrete repaired.
 Keywords: porous concrete, grouting, concrete compressive strength, column, structure

Evaluation of internal pore structure of porous asphalt concrete based on laboratory testing and discrete-element modeling

Permeable pavement constructed with porous asphalt concrete has been more widely used due to its environmental significance (reducing stormwater runoff, recuing traffic noise) and traffic safety advantages. Research regarding permeability and pore structural characteristics of PAC is one of the front topics and yet gaps of knowledge still exist in this area. Pore structure is the primary factor in permeability of porous asphalt concrete (PAC) pavement. The composition and distribution of different pore components of PAC and their impact on permeability and influence factors are worth exploring. This paper evaluates pore structure of PAC using both laboratory tests and discrete element modeling (DEM) simulations. PAC specimens with varying nominal maximum aggregate size (NMAS) and varying gradations were prepared and tested in the laboratory to obtain their total void contents and effective void contents. Permeability tests were conducted to evaluate relationship between pore structure and permeability. A relative indicator of percent effective voids was proposed to evaluate void structure of PAC and was proven to be better indicator than absolute void contents. Laboratory test results revealed that t/NMAS, which is lift thickness divided by NMAS shows better correlation with percent effective voids than NMAS. Interfering size (D2.36) aggregate has a negative impact on percent effective voids and the impact is more significant on smaller size mixes. Discrete-element method (DEM) was utilized to further explore the micro-meso structural characteristics of pore structure of PAC. It was revealed that higher interconnected void content creates more open channel for water to flow and is essentially the cause of increasing permeability. Contributions of interconnected voids in terms of creating void volume is significantly higher than dead-end voids and isolated voids.

Improving the sound absorption behaviour of porous concrete using embedded resonant structures

A relatively new concept of sound absorption herein denominated as Metaporous concrete is presented, consisting of a porous concrete-based sound absorber in which different acoustic resonators are embedded. Two finite element models were implemented, using the fluid-equivalent theory to describe Metaporous concrete solutions. A Helmholtz resonator, porous concrete samples, and a Metaporous concrete prototype were built and tested through experimental techniques based on the use of an impedance tube. The fluid-equivalent complex properties were validated with comparisons between analytical predictions and experimental data. The proposed numerical tools were presented as an efficient methodology to predict the sound absorption behavior of Metaporous concrete solutions, where an excellent approach between the simulated results and experimental data is shown. The parametric study shows efficient strategies to increase the sound absorption behavior and to feature the two sound absorption coefficient peaks provided by Metaporous concrete solutions (i. e. from the acoustic resonator and the porous concrete, respectively). The denominated configuration MPCd was highlighted because of the great proximity of these two sound absorption peaks. The inclusion of non-trivial resonant structures in porous concrete, building a Metaporous concrete, can be proposed as an excellent solution to be adopted for noise control in civil engineering exterior applications.

Recovery and chemical disinfection of foot-and-mouth disease and African swine fever viruses from porous concrete surfaces.

AimsDevelop an effective laboratory method to consistently recover viral loads from porous concrete coupons sufficient for disinfectant efficacy testing. Investigate the role of concrete matrix pH on the recovery of foot‐and‐mouth disease virus (FMDV) and African Swine Fever virus (ASFV) from porous concrete. Compare parameters off FMDV and ASFV inactivation on porous and nonporous surfaces in quantitative carrier tests of a liquid chemical disinfectant.Methods and resultsConcrete test coupons were fabricated from commercial and industrial sources and carbonated by exposure to 5% CO2 in a humidified incubator, lowering the matrix pH. Neither dried FMDV nor ASFV were recovered from high‐pH concrete control coupons. Recovery of infectious virus from lower pH carbonated concrete was similar to stainless steel coupon controls. Exposure to the liquid disinfectant Virkon™ S inactivated FMDV and ASFV on porous concrete.ConclusionsConcrete matrix pH had a greater impact than surface porosity on the ability to recover viable virus from unsealed concrete.Significance and Impact of the StudyConcrete is commonly found in environments where virus decontamination is required. This study demonstrates a reproducible method to recover sufficient viral loads from porous concrete coupons to facilitate quantitative carrier testing. This method provides a basis for evidence‐based validation testing of chemical disinfectants to inactivate pH‐sensitive viruses on unsealed concrete.