The mechanical properties of the concrete using metakaolin additive and polymer admixture

Environmentally friendly and high performance concrete is very import for the applications in sewage andwater treatment industry. Using mineral additives such as fly ash and silica fume has been proven to be an effective approach to improve concrete properties. This paper reports a study of the effect of using both polymer and metakaolin additives together on the mechanical and durability properties of concrete. Different proportions of the combination using two different polymers, metakaolin, and recycled fiber reinforcement have been studied. The effects of water-to-cement ratio and the curing methods have also been compared. At last an optimized mixture and curing method has been suggeste

The mechanical properties of the concrete usingmetakaolin additive and polymer admixture

Environmentally friendly and high performance concrete is very import for the applications in sewage andwater treatment industry. Using mineral additives such as fly ash and silica fume has been proven to be an effective approach to improve concrete properties. This paper reports a study of the effect of using both polymer and metakaolin additives together on the mechanical and durability properties of concrete. Different proportions of the combination using two different polymers, metakaolin, and recycled fiber reinforcement have been studied. The effects of water-to-cement ratio and the curing methods have also been compared. At last an optimized mixture and curing method has been suggeste

Long term durability properties of concrete modified with metakaolin and polymer admixture

Previous studies show that both metakaolin (MK) and polymer can respectively improve certain mechanical and durability properties of concrete. Also, recent studies show that a combination of MK and polymer further enhances the mechanical properties by complement of each other. However, the knowledge of the effect on durability, a critical governing factor of concrete for the applications in extreme environments such as sewage, off-shore and bridge structures, has not been well established yet. This paper reports on a comprehensive study of the effect of metakaolin as a supplementary cementitious material together with polymer as admixture on the durability of concrete at relatively old ages. The results confirmthat replacing Portland cement with 15% metakaolin and an additional 5% polymer (by weight) provide the optimum improvement for Portland cement concrete on both mechanical properties and durability

Flexural Behavior of Normal and High Strength Self-Curing Self- Compacted Concrete Beams of Local Materials

In some construction industries, there are difficulties in achieving the required concrete compaction, Self-compaction is an alternative option. Working with self-compaction self-curing concrete requires a unique approach. This study aims to examine the possibility of producing self- compacting concrete with normal and high self-cure rates. This research observed how both the self- curing and self-compacting concrete behaved under normal and high-strength conditions. Two stages were prepared for this investigation. The first stage of this research studied the effect of a curing agent on the fundamental characteristics of both normal-strength and high-strength self-compacting concrete, with the aim of achieving self-curing self-compacting concrete. The primary variables of this study include the grade of concrete, the type of curing agent, the reinforcing bars, and the dosage of these variables. In the second stage, reinforced concrete beams were cast with one of the two proposed concrete types, and their behavior was studied. The findings were analyzed in terms of the beginning cracking loads, the ultimate loads, and the crack patterns of the testing beams. According to the results, both the normal-strength and the high-strength varieties of self-curing self-compacting concrete are effective in providing structural features, which are absent from the processes of curing and compacting. Curing chemicals are utilized to mitigate the process of water evaporation in self-compacting concrete, hence enhancing the water retention capabilities of self-compacting concretes that possess enough hardened concrete characteristics

An Experimental Study on Modified Concrete Using Partial Replacement of Gravel and Admixtures

Abstract: This study aims to test a concrete specimen with replacement partially of 15 % of the coarse aggregate by pieces of tires and volcanic aggregates and reduce 5% of the water/cement ratio by substituting with 4% percentages of styrene butadiene rubber (SBR) and 1% of superplasticizer. The main concrete components (cement: sand: gravel) were used in weight ratios (1:1.5:3) and a water to cement 0.45 was used and it was considered as a reference sample (Mix1). A water to cement ratio 0.40 was depended for the modified mixtures. Samples were cast for testing the compression strength with sizes 150 ×150 ×150 mm for ages 7 and 28 days. the absorption rate, with a size of 100 ×100 ×100 mm at age 28 days. Moreover, 150 ×150×150 mm for depth of penetration test at the age of 28 days. Briefly, the observed results were exhibited that the partial replacement of normal aggregate in concrete with volcanic aggregate affects negatively on the workability, so 4% of the polymer SBR and 1% of the superplasticizer have improved the workability. The improvement in the workability of concrete contributed to reducing the ratio of water to cement required for mixing compared to ordinary concrete, and this in turn led to an improvement in performance of hardened concrete. In addition, the reduction of the permeability level. The results also illustrated that the replacement of the gravel in the modified mixtures (Mix 3 and Mix 2) reduces the weight of hardened concrete by (10-12%) and (7-9%) compared with conventional concrete, respectively, which makes it suitable for use in mediumweight concrete applications. Moreover, it can be concluded that the strength properties of the modified mix with volcanic aggregate improved by 19-20% compared to that of the unmodified concrete. While the modified concrete by cutting tires showed significant deterioration in the concrete's resistance 21% despite the reduction of concrete permeability

An experimental study of high-performance concrete using metakaolin additive and polymer admixture

In recent years, there has been a growing interest in the use of supplementary cementing materials and polymers to produce high-performance concrete. Utilizing a mineral substance as cement replacement in concrete has less environmental pollution and greatly increases the service life of the concrete structures due to improve the most of concrete properties in compared with conventional concrete. The aim of this project is an experimental study of high-performance concrete using metakaolin (MK) additive as partial replacement of cement and addition of the Styrene-Butadiene rubber (SBR) and Polyvinyl acetate (PVA), to conduct a novel research to investigate the effectiveness of the additives materials on the performance of concrete. It also investigates the effect of additional recycled plastic and glass fibre as reinforcements used in the modified concrete. Firstly, trial mixes of 460 cubes, 24 cylinders and 30 prisms were made to study the setting time, workability, mechanical properties and water absorption of the concrete to find the optimum metakaolin to cement ratio (MK/C), polymer to cement ratio (P/C), water to cement ratio (W/C), and the best curing method among the wet, dry and moist, respectively. The designed concrete mixes have a certain cement/sand/gravel proportion of 1:1.5:3. The trial mixtures were tested for setting time, slump of fresh concrete mix, mechanical properties, including compressive, splitting and flexural strength, and water absorption capacity at age up to 28 days. Three polymers to cement ratios, which are 2.5, 5 and 7.5%, and five metakaolin replacement ratio for the cement, which are 10, 15, 20, 30 and 40%, were studied, respectively. For these mixtures, five W/C ratios, which are 0.35, 0.38, 0.40, 0.45, and 0.50, respectively, were compared. The use of recycled plastic and glass fibre reinforcements took 5% of the total cement weight and tested for splitting and flexural strength testes. The first phase work has shown clear improvement of the performance of concrete modified by partial replacement of cement by metakaolin and adding polymers admixture together. The optimised mix was identified to be that of 5% added polymers included 80% SBR and 20% PVA, 15% metakaolin replacement for cement, 0.45 W/C ratio, and using limestone aggregate as a coarse aggregates and using moist curing method as a curing condition for the concrete. Secondly, the optimum mixture identified in the trial study was further investigated for its mechanical including compressive, flexural, and deformable proprieties at prolonged ages up to 545 days. In addition, a specific durability properties of concrete including water and gas permeability, carbonation penetration, chloride penetration, chemical attack resistance, water absorption, rate of water absorption and the corrosion rate of the steel reinforcement in the concrete. The results show that significant improvement in mechanical properties including compressive, splitting, flexural strength and deformation properties. Also, the results show improvement in durability properties including chemical resistance, water absorption, rate of water absorption, carbonation depth of penetration, chloride ion penetration, water penetration under pressure, water permeability, gas penetration and steel corrosion resistance. The optimum mix of 15% partial replacement of cement by metakaolin, 5% polymer, 0.45 W/C ratio and moist curing condition of the modified concrete produced high-performance concrete more environmental friendly due to improved overall of the mechanical and durability properties of the concrete. Finally, microscopic composition of the hydration products and the corresponding pores structure have been investigated for the optimised mixes based on the material composition analysis and microscopic images obtained using scanning electronic microscope (SEM) and the computed tomography scanner (CT) technologies. Correlation between the mechanical, durability properties and the microscopic phases has been investigated and discussed for a deep understanding of the mechanism of the optimum mixture. SEM and CT scanner technologies provide qualitative and quantitative description of the concrete properties. It’s also, proved that the concrete modified by both of metakaolin and two types of polymers have a significant change in the pores structure of concrete compared with other mixes. Scanning electron microscopy and computed tomography scanner results show that the approach can be effectively applied in high-performance concrete related studies and provide further evidence on mechanical and durability properties of concrete