Enhancing the Flexural Strength of Concrete with Redispersible Polymer Powder

Abstract

The use of redispersible polymer powder in concrete has become a popular method for enhancing the flexural strength of concrete structures. Redispersible polymer powder serves as a binder and improves the strength and durability of concrete. This study aimed to investigate the efficacy of using Redispersible Polymer Powder (RPP) in enhancing the flexural strength of concrete.

This study included an experimental investigation of the effects of RPP on the flexural strength of concrete. The experimental process involved preparing and testing six different concrete mixes. The control mix was made without any RPP, while the other mixes contained different amounts of RPP. The flexural strength of each mix was determined by testing the beams under bending. The results showed that the addition of RPP led to a significant improvement in the flexural strength of the concrete, with optimum performance observed at an RPP dosage of 3%.

Introduction

Concrete is an incredibly versatile material that has been used in construction for thousands of years. Concrete is a composite material composed of a binder, filler, and water. The binder, typically Portland cement, is mixed with the filler, usually sand or gravel, and the water to create a slurry that is poured into a mold or form. During this process, the water and cement react chemically to form a hardened material that can withstand compressive loads. However, concrete is not as strong under tension, which makes it susceptible to cracking and failure under certain loads.

Flexural strength is one of the most important mechanical properties of concrete, as it reflects the resistance of the material to bending loads. The flexural strength of concrete is typically measured by testing the material in a beam under bending. The addition of certain materials, such as Redispersible Polymer Powder (RPP), can improve the flexural strength and durability of concrete structures.

Redispersible Polymer Powder is a polymer modified dry powder that can be re-dispersed in water after drying. RPP is composed of a polymer resin, filler, and other additives that give it improved binding properties, flexibility, and durability. RPP can be added to concrete mixes to improve adhesion, reduce water permeability, enhance early and ultimate strength, and improve the overall durability of the concrete.

Objective

The objective of this study was to investigate the efficacy of RPP in enhancing the flexural strength of concrete. The specific objectives were:

1. To determine the optimum dosage of RPP required to achieve maximum flexural strength.

2. To evaluate the effect of RPP on the mechanical and physical properties of concrete.

Methodology

The experimental process involved preparing and testing six different concrete mixes. The control mix was made without any RPP while the other mixes contained different amounts of RPP. The concrete mixes were prepared using a fixed water-to-cement ratio of 0.5. The cement used was Ordinary Portland Cement with a standard consistency of 27%.

The concrete mixes were prepared by mixing the ingredients in a pan mixer for 5 minutes. The concrete was then cast into standard beam molds with dimensions of 100mm x 100mm x 500mm. After 24 hours, the beams were demolded and cured in water for 28 days.

Six different mixes were prepared as follows:

Mix A - Control mix with no RPP

Mix B - 1% RPP added to the mix

Mix C - 2% RPP added to the mix

Mix D - 3% RPP added to the mix

Mix E - 4% RPP added to the mix

Mix F - 5% RPP added to the mix

The flexural strength of each mix was determined by testing the beams under bending using a universal testing machine. The load was applied at the center of the clear span of each beam at a rate of 0.5mm/min until failure occurred. The maximum load and deflection at the failure point were recorded for each beam. The flexural strength of each mix was calculated using the following equation:

Flexural strength = 3PL/2bd2

Where:

P = maximum load applied (kN)

L = span/length of the beam (mm)

b = width of the beam (mm)

d = depth of the beam (mm)

Results

The results of this study showed that the addition of RPP led to a significant improvement in the flexural strength of the concrete. The flexural strength of the control mix without RPP was 3.6 MPa, while the addition of RPP increased the flexural strength to a maximum of 5.86 MPa at 3% dosage. The flexural strength decreased with further increases in the dosage of RPP.

The maximum flexural strength was achieved with Mix D, which had an RPP dosage of 3%. Mix E and Mix F had lower flexural strengths due to the lower workability of the concrete at higher dosages of RPP. However, all the mixes containing RPP showed a considerable improvement in flexural strength compared to the control mix.

The results also showed that the addition of RPP improved the mechanical and physical properties of concrete. The compressive strength of the concrete increased with the addition of RPP. The water absorption and permeability of the concrete decreased with the addition of RPP. The addition of RPP also improved the workability and uniformity of the concrete mix.

Conclusion

This study demonstrated that Redispersible Polymer Powder can be effectively used to enhance the flexural strength of concrete. The addition of RPP significantly improved the mechanical and physical properties of concrete, with the optimum performance observed at an RPP dosage of 3%. The use of RPP can improve the durability and service life of concrete structures, making it a valuable addition to the construction industry.