self-compacting concrete

     Today, the wastes remaining from concrete degradation is considered as an environmental problem and is one of the biggest challenges in the building industry. Accordingly, many researchers have decided to re-use the materials of aggregates from More

     Today, the wastes remaining from concrete degradation is considered as an environmental problem and is one of the biggest challenges in the building industry. Accordingly, many researchers have decided to re-use the materials of aggregates from degradation in concrete production cycles. In this paper, attempts were made to assess and if possible to promote the mechanical and durability characteristics after the addition of nano-silica and micro-silica to self-compacting concrete containing recycled aggregates (obtained from worn concrete degradation). One of the points to be considered in this paper was the attempt to use tests such as half-pole testing and concrete wave velocity. In this regard, 72 mixture designs were studied in 8 collections. In these mixture designs, with respect to the content of recycled aggregates, the nano- and micro-contents were changed. Then, the samples underwent mechanical tests including compressive strength and tensile strength, and durability tests including corrosion potential, concrete wave velocity (ultrasonic) and electrical strength. After the tests, with an increase in the use of nano-silica and micro-silica, the efficiency and fluidity of the fresh concrete were reduced, and compressive strength and tensile strength were increased. Also, at fixed strength, nano-silica caused less efficiency and fluidity than micro-silica and also, with an increase in the content of recycled aggregates in concrete, efficiency and fluidity as well as compressive strength and tensile strength of concrete were reduced. Manuscript profile

Open Access Article

8 - Evaluation of self-compacting concrete and ordinary concrete, by core method, in deep foundations
nobakht bakhtyari jamshid esmaili mehdi Amri

Situ concrete piles, are the most widely used type of deep foundation. In Iran experience shows, that technical problems and economic performance by avoiding the use of ordinary concrete with a slump an extremely high in these types of candles. Poor and low compress res More

Situ concrete piles, are the most widely used type of deep foundation. In Iran experience shows, that technical problems and economic performance by avoiding the use of ordinary concrete with a slump an extremely high in these types of candles. Poor and low compress resistance, durability and high water permeability in the subsurface environment, the effects of this type of concrete planning. The excellent strength, permeability to ensure proper compaction, concrete ‌ ease and speed up the planning run, the significant advantages of self-compacting concrete. These benefits are especially situ concrete pile planning, most appear to be. In This paper compares core strength situ by taking samples from two typical arrangement of pile ordinary and self-compacting concrete and important results have been obtained. The core samples, to a depth of 14 m in which different levels of ground benchmark are tested show that the use of self-compacting concrete has technical  and economical advantages, and notable administrative lead to greater uniformity in resistance acquisition, located in the upper part of the pile is. This section, the maximum stresses due to vertical and lateral loads. Therefore, the use of self-compacting concrete in deep foundations, can widely replace traditional methods. Manuscript profile

Open Access Article

9 - Determination of the Properties of Self-compacting Concrete Containing Metakaolin as a Replacement for Cement and Limestone Powder
Seyed Fathollah Sajedi Milad Orak

10.30495/civil.2022.689514

Today, the tendency to use self-compacting concrete (SCC) is expanding due to its advantages. Manufacturing of SCC requires increasing the amount of cement used, which will result in the more environmental pollution due to the increased cement production, trying to use More

Today, the tendency to use self-compacting concrete (SCC) is expanding due to its advantages. Manufacturing of SCC requires increasing the amount of cement used, which will result in the more environmental pollution due to the increased cement production, trying to use pozzolans to reduce cement consumption will be an essential step towards sustainable development. So, efforts to use pozzolans to reduce cement consumption will be an essential step towards sustainable development. Accordingly, in this study, by replacing a part of the cement and limestone powder with metakaolin as an active pozzolan, some properties of the produced concrete including rheology, mechanical and durability were evaluated. For this aim, metakaolin with 10%, 15%, 20%, 25% and 20%, 25%, 30%, 35% replaced the cement and limestone powder, respectively (without changing the cement content). The self-compacting properties of the concrete specimens were evaluated in the form of slump flow tests, L-box, U-box and J-ring, as well as mechanical properties including compressive and splitting tensile strength, and durability including water penetration depth and rapid chloride ion penetration (RCPT). The results present that the utility of metakaolin in the manufacturing of self-compacting concrete as an independent alternative to the part of cement and limestone powder has improved the mechanical properties of concrete, but has reduced its consistency. In order to solve this problem, it is necessary to increase the percentage of consumable superplasticizer used until it reaches the desired consistency level. Replacement of cement by 20% metakaolin reduced water permeability and RCPT by 35% and 20%, respectively, and replacing of the limestone powder by 35% metakaolin reduced water permeability and RCPT by 70% and 35%, respectively. Manuscript profile

Open Access Article

10 - An experimental study on effects of glass fiber and Metakaolin on the rheological, mechanical, and durability properties of self compacting concrete
Mir Pouya Naseri Alavi Payam Shafiei Hassan Javanshir

     Previous studies has shown that reinforced self-compacting concrete with fiber is more suitable for structural performance. The purpose of this study was to evaluate the effects of Metkaolin and alkali resistant glass fibers on the performance o More

     Previous studies has shown that reinforced self-compacting concrete with fiber is more suitable for structural performance. The purpose of this study was to evaluate the effects of Metkaolin and alkali resistant glass fibers on the performance of self-compacting concrete. In this study, the rheological properties (L-Box, Slump flow, T50) and mechanical properties (compressive strength, tensile and flexural strength), and durability (chloride ion penetration and water absorption) have been investigated. The results of the experiments showed that by increasing the amount of fiber, the concrete performance decreases. It was also found that the glass fiber had no positive effect on the compressive strength of the concrete. The tensile and flexural strength of self-compacting reinforced concrete increases with increasing fiber content. Durability studies have shown that the presence of glass fiber initially increases the resistance to chloride ion penetration and then reduces it, and also increases the gradual absorption of concrete water. The results of the experiments showed that the simultaneous presence of Metkaolin and glass fibers with optimal percentages can significantly improve the mechanical properties and durability of self-compacting concrete Manuscript profile

Open Access Article

11 - Experimental and numerical evaluation of rheological and mechanical properties of self-compacting concretes containing steel fibers and PET using response surface method (RSM)
hamed basser Taleb Moradi Shaghaghi hasan afshin saleh ahari saeed mirrezaei

In the modern characteristics of concrete design based on daily needs, the use of recycled materials is an important and basic principle. Therefore, in the present study, PET (Polyethylene Terephthalate) has been substituted for fine aggregates in self-compacting concre More

In the modern characteristics of concrete design based on daily needs, the use of recycled materials is an important and basic principle. Therefore, in the present study, PET (Polyethylene Terephthalate) has been substituted for fine aggregates in self-compacting concrete. The aim of this study is to produce and optimize the mechanical and rheological properties of environmentally friendly self-compacting concretes. Input variables in the mixtures include (PET) as a substitute for a percentage of fine aggregates, steel fibers, powder stone as a substitute for a percentage of cement weight, and lubricant as a percentage of powder material weight. The studied responses are slump flow, L-box ratio (H2 / H1), compressive and tensile strengths. Mixing schemes were designed and studied using the Central Composite Design (CCD) method, which is one of the RSM (Response Surface Methodology) methods. The results demonstrated that with increasing PET, the rheological and mechanical properties of the mixtures decreased while the fibers effectively improved the reduction of strengths. Applying mathematical models provided by ANOVA, multi-objective optimizations were performed to maximize compressive strength by the RSM method and an optimal mixing scheme based on experimental results was proposed. Manuscript profile

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