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Open Access Article
1 - Determination of optimal percent mixing of cardboard waste in production of non-load bearing concrete
Daryoush Yousefi Kebria Seyyedeh Fatemeh Seyyedalipour Mehdi Dehestaniincineration and disposal methods for their waste production. Hazardous substances contained in thesewastes can contaminate the environment and cause a risk for the human health. Many recent studiesshow that some of the paper and cardboard industry wastes can be used as Moreincineration and disposal methods for their waste production. Hazardous substances contained in thesewastes can contaminate the environment and cause a risk for the human health. Many recent studiesshow that some of the paper and cardboard industry wastes can be used as raw material in theconstruction industry. The aim of this study was to determine the optimal percent mixing of cardboardwaste in production of non-load bearing concrete.Materials and method: In this study, two kinds of recycled paperboard mill wastes (type 1: wastecontains cardboard and sand and type 2: waste containing nylon, cardboard and Yonolit) that have themost volume of the wastes were used. Physical and microbial characteristic of wastes were measuredaccording to ASTM. As well as the chemical composition of the waste consists of various elementswere measured by using an electron microscope. After preparation of the samples, the required testswere carried out to determine the optimal mixture of waste in concrete at the ages of 7, 14 and 28 daysrespectively.Results: Since the pH of fresh concrete containing waste is greater than 12, can be sure that therewill not be any microbiological problem. In general, the use of waste in concrete production reducesthe compressive strength of the samples. Comparing the compressive strength of concrete containingwaste type 1 and concrete samples containing both waste types shows that reducing the amount ofwaste type 2 in compare with waste type 1 improves concrete strength. The results of dry density testshow the density decrease of concrete samples containing waste by increasing the percentage of wastereplacing in the sand. Also using of waste type 2 causes lighter concrete samples in compare withusing waste type 1. Optimal amounts of waste replacement instead of sand for samples containingwaste type 1 and type 2, 70% and 75% ,respectively, as well as for samples containing both wastetypes, 49% of waste type 1 and 21% waste type 2.1- Assistant professor, Department of Civil & Environmental engineering, Babol Noshirvani University ofTechnology, Babol, Iran.2- MSc in Environmental engineering Department of Civil & Environmental engineering, Babol NoshirvaniUniversity of Technology, Babol, Iran.3- 1-Assistant professor, Department of Civil & Eenvironmental engineering, Babol Noshirvani University ofTechnology, Babol, Iran.J.Env.Sci,TechJ.Env. Sci. Tech., Vol 17, No.3, Autumn 2015203Conclusion: According to the results, in terms of economic and environmental benefits, the use ofwaste type 1 in the production of concrete for the lower use of cement is more satisfactory. The use ofpaperboard mill wastes in the production of concrete due to environmental and economical efficiency(profitability and employment, reducing the cost of transferring waste to landfills, reducing structuralweight, using waste instead of buying sand and reduce the environmental pollution caused byincineration and landfilling) is noticeable. Manuscript profile -
Open Access Article
2 - Increasing of the cement strength and corrosion resistance of rebar inside it using silica nanoparticles
Fatemeh Abdi -
Open Access Article
3 - Synthesis of Environmentally Friendly Activated Alkali Concrete (Geopolymer) Based on Bentonite
A Esparham -
Open Access Article
4 - Investigating the effect of nanosilica on the compressive strength of hard concrete by considering Atomic Force Microscopy (AFM) examinations
seyed mohammad mahdi shafiei mahboobeh pirizadeh Ebrahim ZolgharneinThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressi MoreThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressive strength of the materials. The hydration process and formation of C-S-H and Calcium Hydroxide (CH) was examined using Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR). Results indicate an increase in compressive strength using 1, 3 and 5% of nanosilica to concrete replacement by volume in comparison to the control mix (without nanosilica). The optimum concrete replacement to yield maximum strength was of the 5% nanosilica content. Comparing the 56 day results for the 3 and 5% of nanosilica replacement samples, notice the same percentage of C-S-H formation of 83 and 85%, respectively Manuscript profile -
Open Access Article
5 - Effect of Basalt and Polypropylene Fibers on Unconfined Compressive Strength of Cement-Stabilized clay, an Experimental Approach
Seyed Hadi Sahlabadi Meysam Bayat Mohsen Mousivand Mohsen Saadat -
Open Access Article
6 - Examining the Mixing Plan and the Results of the Plastic Concrete
Abolfazl Ostovarzijerdi Akbar Ghanbari Mohammad Karkon -
Open Access Article
7 - Compressive Strength and Ductility of Concrete Wrapped by CFRP
Seiyed Ali Haj Seiyed Taghia Behzad Saeedi Razavi Hamid Reza Darvishvand -
Open Access Article
8 - Mechanical Properties of Low Strength Concrete Incorporating Carbon Nanotubes
Meysam Morsali Reza Farokhzad -
Open Access Article
9 - Investigating properties of fresh and hardened self-compacting concrete made of recycled aggregates
Pouria Javadi Ali Delnavaz -
Open Access Article
10 - Mix Design Selection For Old and New Generation of SuprePlasticizers
Navid Afshari Seiyed Ali Haj Seiyed Taghia -
Open Access Article
11 - The Effect of Compressive Strength Reduction of Column Section Expose due to Freezing-Thawing Cycles on the Seismic Performance of Bridges
Saeideh Alsadat Mousavi Mehran Seyed Razzaghi -
Open Access Article
12 - Investigation of mechanical and durability properties of lightweight concrete containing Pumice
Amirmohammad Soleimani Seyed Amir Hossein Hashemi -
Open Access Article
13 - The possible use of Sewage Sludge Ash (SSA) in Self-Consolidating Concrete (SCC) for environmental sustainability
Mohamadreza Khanban Mahdi Mahdikhani -
Open Access Article
14 - A Study on the Quasi-static Compression Behavior of 5056 Aluminum Alloy Foams
Sadegh Soltani Hamed Deilami Azodi Seyed Hossein Elahi -
Open Access Article
15 - Effect of temperature and activator molar of Na2O to SiO2 in the process of synthesis and microstructure of cement geopolymer
M Asadi A Nemati R Naghizadeh K Arzani J Fahim -
Open Access Article
16 - Prefabricated Concrete Elements for the facade Industry with Nano cement composites containing silica fume, nano-silica, and TiO2
Sayedeh Fatemeh Khoshkalam Soleimandarabi Raheleh Rostami Mehdi Nezhadnaderi -
Open Access Article
17 - Mechanical Properties of Concrete Containing Tire Rubber Particles toward Constant Development
Hasan Sousani Amir Mahmoudzadeh -
Open Access Article
18 - Investigation of effective parameters on compressive strength, specific electrical resistance and water absorption of lightweight pervious concrete
Shahriar GholaminNoveirsar Morteza Jamshidi Rahmat MadandoustPervious concrete is a special type of lightweight concrete with low or even zero slump, which consists of cement, coarse aggregate, a limited percentage of fine aggregate (or no fine aggregate), various chemical and pozzolanic additives. In this article, structural LEC MorePervious concrete is a special type of lightweight concrete with low or even zero slump, which consists of cement, coarse aggregate, a limited percentage of fine aggregate (or no fine aggregate), various chemical and pozzolanic additives. In this article, structural LECA with a volumetric weight of 750 kg/m3 and a fixed water-to-cement ratio (W/C = 0.3) was used to make lightweight pervious concrete and the effect of different ratios of lightweight aggregate to cement (A/C) including 1.5, 1.8, 2.1, 2.4, 2.7, 3, total porosity and volume percentage of cement paste on compressive strength , specific electrical resistance and percentage of water absorption of lightweight pervious concrete aged 28 days were investigated. With the increase of A/C ratio from 1.5 to 3, the volume of cement paste decreased from 30.873% to 15.436% in the samples and the total porosity increased from 21.64% to 38.08%, which led to a decrease Specific electrical resistance decreased from 11.45 to 6.841 , compressive strength decreased from 13.27 MPa to 4.37 MPa, and water absorption increased from 11.185% to 12.695% in lightweight pervious concrete samples. The results of this research showed the improvement of physical properties and the decrease of mechanical properties and durability of lightweight pervious concrete containing LECA. Manuscript profile -
Open Access Article
19 - Consideration of the Mechanical Properties of Sawdust Concrete
ali foroughi asl sahar nozouhourConcrete as the most commonly used materials in the construction is of particular importance and according to structures retrofitting in various lateral forces to reduce human and economic damage, light and its impact are considered on a variety of structures. Concrete MoreConcrete as the most commonly used materials in the construction is of particular importance and according to structures retrofitting in various lateral forces to reduce human and economic damage, light and its impact are considered on a variety of structures. Concrete with lower density can lead to lighter structures in a way that using concrete with specific gravity of less than 1900 Kg/m3 and compressive strength more than 17 MPa in reinforced concrete structures is considered by many design engineers. Using of Sawdust in mix design of concrete is one way to reduce the density of concrete. In this research the percentage replacements of sand by sawdust were (0%, 15%, 25% and 35%). The size of test sample concrete adopted was 100x100x100 for compressive strength and 200x100 for tensile strength. The samples were removed from their moulds after 24 hours and allowed to cure 7,14 and 28 days. The results show that 25% Sawdust replacement of Sand with the compressive strength of 19MPa and density of 1904 is the optimal choice. Manuscript profile -
Open Access Article
20 - Investigation of the effects of high temperature on compressive and tensile strength and modulus of elasticity of alkali-activated concrete
Mohammadhossein MansourghanaeiIn recent years, improving the mechanical properties of alkali- activated concrete with the aim of being superior compared to those of the conventional concrete and reducing environmental hazards caused by the lack of mineral resources and release of toxic carbon dioxid MoreIn recent years, improving the mechanical properties of alkali- activated concrete with the aim of being superior compared to those of the conventional concrete and reducing environmental hazards caused by the lack of mineral resources and release of toxic carbon dioxide gas (in cement production process) has been noticed by civil engineering researchers. In this laboratory research, a mixing design of ordinary concrete containing Portland cement with a grade of 500 kg/m3 and a mixing design of alkali-activated concrete based on blast furnace slag were made. In order to check the mechanical properties, tests of compressive strength, tensile strength and modulus of elasticity of concrete were performed under the temperatures of 21 and 600 ℃ at the age of 90 days of curing. Based on the results, applying high temperature (600 ℃) to concrete samples caused a 42% and 15% drop in compressive strength, a 56% and 21% drop in tensile strength, and a 63% and 49% drop in modulus of elasticity for ordinary and alkali-activated concretes, respectively. The compressive strength of alkali-activated concrete was 11% and 64% more than that of the normal concrete at 21 and 600 ℃, respectively. The tensile strength of alkali-activated concrete exhibited a 9% decrease and 63% superiority compared to normal concrete at 21 and 600 ℃, respectively. The elasticity modulus of alkali-activated concrete was 16% and 62% higher than that of the normal concrete at 21 and 600 ℃, respectively. The results of the scanning electron microscope images are in accordance with the other test results of this research. Manuscript profile -
Open Access Article
21 - Investigation of mechanical properties and effects oftypicalaggregates in preparation of pervious concrete
Majid Rostami eman Bahramiperviousconcrete is a special kind of concrete which has a high degree of porosity and one of its major applications is in the roadway pavements. Todays, due to transportation importance, using of new materials in land, sea, airand railway transportation infrastructures Moreperviousconcrete is a special kind of concrete which has a high degree of porosity and one of its major applications is in the roadway pavements. Todays, due to transportation importance, using of new materials in land, sea, airand railway transportation infrastructures is among hot research topic. Pervious concrete is one kindof the rigid pavement which has great advantages include; high permeability, proper hydraulic conduction, surface water filtration and to the underground water sourcesinjection. Despite having many advantages, its low compressive strength is one of its disadvantageswhich indicate demands for deeperstudies to increase the compressive strength of this type of concrete. In this research, a series of experimentaltestsis done on typical aggregate samples with different material and graduation, in first step their physical and specious properties was examined and then after preparation of different mix designs for making perviousconcrete sample, properties of obtained concrete samples like: permeability, porosity, and compressive strength were investigated, after that, conducting the tests on various specimens, the results were analyzed. Finally, based on the results and analyses of the conducted tests, the optimum mix designs were introduced based on their application. Manuscript profile -
Open Access Article
22 - An investigation into the properties of concrete made from concrete debris and effects of the three-step mixing procedure on it
Mohammad Khazaei Abdolkarim Abbasi DezfouliUsing by-product materials in making concrete is the recent development in the advanced concrete technology. The products obtained from experimental crushed concrete can be used in constructing the new concrete. Recent research revealed that using crushed concrete as pa MoreUsing by-product materials in making concrete is the recent development in the advanced concrete technology. The products obtained from experimental crushed concrete can be used in constructing the new concrete. Recent research revealed that using crushed concrete as partial replacement of sand and coarse aggregate, using traditional mixing procedure, reduced the compressive strength. In the present research, the special procedure of mixing concrete in three steps and its effect on concrete strength parameters have been evaluated. The aim of this study is to use crushed tested concrete as partial replacement 25% (mix A) and 50% (mix B) of conventional sand and aggregate. Also for experimental comparison the control mixes were casted with traditional sand and aggregate. Superplasticizer based on carboxylate was used in the mixes. This procedure causes proper efficiency, proper coating on the aggregate and protection of the alkaline reaction of the aggregate. The method of mixing was carried out in three steps 1: Coarse aggregate + 50% water + 50% cement: mixing time 30 seconds to 1 minute, step 2: Adding 50% cement + 25% water + superplasticizer + sand: mixing time 2 minutes, step 3: Adding 25% water: mixing time 3 minutes. All the mixing time is about 6 minutes. Six specimens of 15 cm concrete cubes for each designed mixes were casted. Densities, water absorption, electric resistance (an indication of permeability and durability of concrete) and compressive strength tests were carried out. Tests were performed at 7 and 28 days. As a result, the designed mix (A) presented the higher electric resistance and compressive strength at 28 days. According to the obtained appropriate resistance, it can be deduced that with a special mixing method, crushed concrete can be used in the composition of concrete that is cost-effective in terms of environmental and resistance. Manuscript profile -
Open Access Article
23 - Comparative Study of the Mechanical Properties of the Concrete Reinforced with Industrial Steel Fibers and Recycled Metal Chips
Farhad Jireh Ziaaddin Zamanzadeh Leila JaliliIn recent years, most of the experimental studies have been performed on the mechanical behavior of reinforced concrete with recycled and industrial steel fibers in foreign countries, and it is necessary to conduct studies on fiber reinforced concrete made from existing MoreIn recent years, most of the experimental studies have been performed on the mechanical behavior of reinforced concrete with recycled and industrial steel fibers in foreign countries, and it is necessary to conduct studies on fiber reinforced concrete made from existing materials in our country. In this paper, experimental and numerical research on the mechanical behavior of the fiber concrete has been conducted. In the experimental program, first, by modeling the mix design presented in previous research for recycled fiber concrete, two mixing designs were determined in accordance with the available materials of the country, so that by adding two different types of steel fibers, the desired slump flow is obtained. The effect of industrial fibers and recycled metal chips on the compressive and splitting tensile behavior of fiber reinforced concrete was investigated by performing compressive and tensile tests. The addition of industrial fibers and recycled metal chips has slightly reduced the indirect compressive and splitting tensile strength of the concrete. In the simulation and modeling of finite element compression tests, the formation of cracks in the concrete elements surrounding metal chips elements, confirmed the occurrence of stress gradients in these concrete elements, which led to a reduction in the compressive strength of the fibre reinforced concrete. Manuscript profile -
Open Access Article
24 - behavior pattern of Compressive and tensile strength of structural lightweight concrete Consisting perlite, leca and Steel Fiber
Hossein Shaddel milad kheiri ghoje biglu abdollah enayati tekleConsidering that the weight of the structure increases the forces involved, especially the lateral forces such as earthquakes, so for this reason, as far as we can take the building path, we have been able to withstand earthquake resistance to the structure. Since, one MoreConsidering that the weight of the structure increases the forces involved, especially the lateral forces such as earthquakes, so for this reason, as far as we can take the building path, we have been able to withstand earthquake resistance to the structure. Since, one of the commonly used methods for producing the light eight concrete, utilizes the light weight aggregates with significant role in the concrete strength, proposing the optimized mix-design for the light weight concrete appears to be important. The result of experiments on 140 samples are representative of achieving to structural lightweight concrete according to ASTM C330 Standard which limits the specific gravity of structural light weight concrete to 1850 kg/cm3 and limits the minimum compressive strength of structural lightweight concreteto170 kg/cm3. Specific gravity and compressive strength of samples could be reached to defined limitation according to ASTM C330 Standard by using the very little particles of pozzolans and by changing in mix design Manuscript profile -
Open Access Article
25 - Experimental Study of Compressive Strength of Geopolymer Concrete Based on XRF and SEM Analysis
Mohammadhossein Mansourghanaei Morteza Biklaryan Alireza MardookhpourIn this research, three mixing designs were made of geopolymer concrete containing 92, 96 and 100% composite blast-furnace slag including 8, 4 and 0% nanosilica, respectively. After performing the compressive strength test and selecting one of these three designs a MoreIn this research, three mixing designs were made of geopolymer concrete containing 92, 96 and 100% composite blast-furnace slag including 8, 4 and 0% nanosilica, respectively. After performing the compressive strength test and selecting one of these three designs as the optimal design in terms of superior mechanical properties, by adding 1 and 2% of polyolefin fibers to the optimal design, two more designs were made of geopolymer concrete. Concrete specimens were subjected to compressive strength tests (at 7, 28 and 90 days of curing), XRF (at 7 days of curing), and SEM (at 90 days of curing). The results were evaluated and compared with the results of a mixing design made of ordinary concrete containing Portland cement. The results of the analyses in this research exhibited the superiority in mechanical and microstructural properties of the geopolymer concrete in comparison with the ordinary concrete at all ages. At the 90-day curing age, as the best age in terms of performance, the minimum (62.43 MPa) and maximum (82.96 MPa) compressive strength values were obtained in designs 1 and 4, respectively. At this age, adding up to 8% nanosilica in geopolymer concrete enhanced the compressive strength up to 21.94% and adding up to 2% of fibers reduced the compressive strength up to 22.49% in this type of concrete. The results of XRF and SEM analyses overlapped with each other and were in accordance with the results of the compressive strength test. Manuscript profile -
Open Access Article
26 - Statistical Analysis of the Impact of Cold Joint on the Compressive Strength of Concrete Made by the National Method for Concrete Mix Design
Arash rafiei Ah karimiOne of the common problems in the implementation of concrete structures is seam or cold joint. The discontinuity in concrete body can cause structural weakness, increased permeability, reduced durability, corrosion of the rebar, and bad appearance of concrete. In this s MoreOne of the common problems in the implementation of concrete structures is seam or cold joint. The discontinuity in concrete body can cause structural weakness, increased permeability, reduced durability, corrosion of the rebar, and bad appearance of concrete. In this study, in order to evaluate the effect of cold joint on compressive strength of concrete, 192 cubic samples by national method of mix design in 4 modes, in which 48 samples without cold joint, 48 samples with horizontal cold joint, 48 samples with vertical cold joint, and 48 samples with diagonal cold joints were concreted in a 24-hour time interval. After 28 days of treatment with standard conditions by pressure cylinder device, the compressive strength of the samples was evaluated. After evaluating the results of the experiments, the values of the effect of cold joint on the compressive strength of the samples, the uncertainty and the probability of failure of the samples have been investigated. The results of analyzes indicate that, generally, the creation of a cold joint in concrete reduces the compressive strength of concrete. However, the reduction in compressive strength depends on the degree of cold joint to its angle. Also, the size of surface angle of the cold joint is also affected by the probability of failure. Manuscript profile -
Open Access Article
27 - Experimental Study of Engineering Specifications of Concrete Containing Local Mineral Pozzolan based on XRD and SEM Analyses
Mojtaba Rangrazian Rahmat Madandoust Reza Mahjoub Mehdi RaftariGlobal warming and its effects on the environment can be considered as the important crises facing humans. Finding a method to reduce cement consumption can be an effective step in controlling the annual increase in global temperature. In this research, in order to find MoreGlobal warming and its effects on the environment can be considered as the important crises facing humans. Finding a method to reduce cement consumption can be an effective step in controlling the annual increase in global temperature. In this research, in order to find the optimal mixing design for replacing local mineral pozzolan instead of a part of cement, two mixing projects with four types of 5, 10, 15 and 20 percent by weight replaced a part of concrete cement.The compressive strength and concrete quality tests were evaluated in the specimens. The constituent elements of concrete and the effect of adding local mineral pozzolan were investigated using the XRD analysis, as well as the morphology and microstructural behavior of concrete with the SEM test. The results exhibited that the best replacement value of cement by pozzolan in concrete is equivalent to 15 percent by weight of cement. Pozzolanic samples increase the strength by 24% compared to plain cement concrete (PCC) samples. Optimal pozzolanic reaction reduced the amount of portlandite and calcite in concrete. Also, this pozzolan reduced the pores, increased the improvement and integrity of the interfacial transition zone (ITZ) in concrete in comparison with plain cement concrete. Considering the effects of this pozzolan on strengthening the structure and reducing the consumption of cement in concrete, the studied local mineral pozzolan can be introduced as a green material that reduces cement by increasing the strength of concrete and is environmentally friendly. Manuscript profile -
Open Access Article
28 - Application of Artificial Neural Networks (ANN) to Predict Geomechanical Properties of Asmari Limestones
Mahdi Razifard Mashallah Khamechiyan Mohammad Reza Amin‐Naseri -
Open Access Article
29 - Effect of using nano-silicates in concrete strength properties (A laboratory study)
Hassan Heydari Mofrad -
Open Access Article
30 - Estimating of uniaxial compressive strength by using point load index for travertine rock of Mahallat
Saied Dehghan Ghasem Sattari -
Open Access Article
31 - Experimental Investigation of Strength and Water Absorption of Concrete Containing Desert Sand
Amir Hamzeh Keykha Jalal Najmaddini -
Open Access Article
32 - Laboratory evaluation on the effectiveness of polypropylene fibers on the strength behavior of CKD-stabilized Soil
Sadegh Ghavami Hamid Jahanbakhsh Fereidoon Moghadas Nejad -
Open Access Article
33 - Investigation of nano-silica effects on Coarse-grained soil’s compressive strength: A case study for Aras Free Trade Zone (AFTZ)
Farhad Pirmohammadi Alishah -
Open Access Article
34 - Experimental Study on Wastewater Application for Cement Mixing in Concrete
Mohammad Pordel Nezami Mohamad Aslalinezhad Fard Mahdi Aslalinezhad Fard -
Open Access Article
35 - Combined Porcelain Ceramic and Recycled Concrete Aggregates Used as Replacement for Coarse Aggregates in Concrete
Sayed Behzad Talaeitaba Maedeh Dehghani -
Open Access Article
36 - Experimental investigation of Carbon, Glass and Steel fibers effect on failure strength and slump of standard concrete samples
Sohrab hosseini kheirabad Ehsan Kazeminezhad Soroush Safakhah -
Open Access Article
37 - Estimating an appropriate plastic concrete mixing design for cutoff walls to control leakage under the earth dam.
A Pashazadeh M Khosravi N Ganjian -
Open Access Article
38 - The effect of physical and mechanical properties on the abrasion resistance of artificial stones produced with granite waste
Seyyed Mohammad Javad Mousavi Reza Abedinzadeh Mohammad Reisi -
Open Access Article
39 - Investigation of Effective Parameters on Compressive Strength, Specific Electrical Resistance and Water Absorption of Lightweight Pervious Concrete
shahriar gholamin noveirsar مرتضی جمشیدی رحمت مدندوستPervious concrete is a special type of lightweight concrete with low or even zero slump, which consists of cement, coarse aggregate, a limited percentage of fine aggregate (or no fine aggregate), various chemical and pozzolanic additives. In this article, structural LEC MorePervious concrete is a special type of lightweight concrete with low or even zero slump, which consists of cement, coarse aggregate, a limited percentage of fine aggregate (or no fine aggregate), various chemical and pozzolanic additives. In this article, structural LECA with a volumetric weight of 750 kg/m3 and a fixed water-to-cement ratio (W/C = 0.3) was used to make lightweight pervious concrete and the effect of different ratios of lightweight aggregate to cement (A/C) including 1.5, 1.8, 2.1, 2.4, 2.7, 3, total porosity and volume percentage of cement paste on compressive strength , specific electrical resistance and percentage of water absorption of lightweight pervious concrete aged 28 days were investigated. With the increase of A/C ratio from 1.5 to 3, the volume of cement paste decreased from 30.873% to 15.436% in the samples and the total porosity increased from 21.64% to 38.08%, which led to a decrease Specific electrical resistance decreased from 11.45 to 6.841 , compressive strength decreased from 13.27 MPa to 4.37 MPa, and water absorption increased from 11.185% to 12.695% in lightweight pervious concrete samples. The results of this research showed the improvement of physical properties and the decrease of mechanical properties and durability of lightweight pervious concrete containing LECA. Manuscript profile -
Open Access Article
40 - Investigation of the Reduced Graphene Oxide Effect on the Concrete Strength, Impedance and Corrosion Resistance of Rebar Inside
fateme abdi Houdhyar Eimani KalesarIn this work, to investigate the effect of reduced Graphene Oxide nanoparticles on the strength of concrete and the corrosion resistance of rebar inside it, Graphene Oxide nanoparticles were added to the mortar with different weight percentages of cement. The strength MoreIn this work, to investigate the effect of reduced Graphene Oxide nanoparticles on the strength of concrete and the corrosion resistance of rebar inside it, Graphene Oxide nanoparticles were added to the mortar with different weight percentages of cement. The strength of concrete was evaluated by measuring the compressive strength of 7 days and 28 days and comparing with the results of the control sample. To investigate the effect of reduced Graphene Oxide nanoparticles on the corrosion resistance of rebar inside it, polarization and EIS tests were performed in a 3.5% salt solution. The results showed that the addition of reduced Graphene Oxide nanoparticles increases the compressive strength and electrical impedance of the concrete. It was also found that there is an optimal value that the addition of Graphene Oxide nanoparticles more than that value causes a relative decrease in concrete strength and electrical impedance. Finally, by simulating the equivalent circuit, the reason for the decrease in impedance and as a result the corrosion resistance by adding more than the optimal value was investigated. Manuscript profile -
Open Access Article
41 - Prediction of compressive strength of concretes containing micro silica subject to carbonation using neural network
Ali DelnavazConcrete materials are exposed to special weather conditions, corrosion and significant damage. For this purpose, the effect of 28-day compressive strength changes on the samples studied in this study was investigated by considering the simultaneous effect of chloride i MoreConcrete materials are exposed to special weather conditions, corrosion and significant damage. For this purpose, the effect of 28-day compressive strength changes on the samples studied in this study was investigated by considering the simultaneous effect of chloride ion penetration and carbonation phenomenon. For this reason, in the first case, the samples are exposed to carbon dioxide once and then to chloride ions. In the latter case, only samples under the influence of chloride infiltration are examined. To make the samples, which include 9 mixing designs, three water-to-cement ratios of 0.35, 0.4 and 0.5 and three percent of 0%, 7% and 10% silica fume have been used. Finally, an optimal model is introduced to predict the compressive strength of concrete containing micro silica exposed to carbonation using artificial neural network. Also, a relation for estimating compressive strength based on the ratio of water to cement and the amount of silica is presented. Manuscript profile
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