THE IMPACT OF LATEX ON MODIFIED CONCRETE BRICKS [PDF]
in CIVIL ENGINEERING PROJECT TOPICS AND MATERIALS, Projects on August 8, 2020CHAPTER ONE
INTRODUCTION
- Background of Study
Polymer cement concrete (PCC) is a concrete polymer composite (CPC) where both cement paste and polymer serve as binders. PCCs are most frequently made by adding a polymer emulsion (i. e. latex) to the fresh concrete mix.
The performance of (PCC) is reviewed with a special focus on properties for concrete block paving; both mechanical properties like abrasion resistance, impact resistance and tensile/flexural strength and durability related properties like freeze/thaw resistance, capillary suction and chemical resistance. Specific examples for each of the properties are given and the relevance for concrete block paving is discussed.
The importance of choosing the right principle for comparing the PCC with ordinary concrete, and the right type of polymer, are stressed. Depending on type of polymer, dosage of polymer and principle of comparison, a PCC material may provide properties of interest for concrete block paving; improved abrasion resistance, increased impact and tensile strength, improved freeze-thaw resistance, lower capillary suction and improved chemical resistance. The most cost/effective dosage of dry polymer in PCC is usually 10 % of the cement weight.
Water reducers (ASTM C494) and superplasticizers (ASTM C1017) can be used to reduce the water-cement ratio, resulting in reduced permeability and less absorption of corrosive chemicals. Polymer admixtures, such as styrene-butadiene latex, used in the production of polymer-modified concrete, greatly reduce the permeability of concrete to many corrosive chemicals. A typical dosage of latex admixture would be about 15% latex solids by weight of cement.
Certain integral water-repelling admixtures, also called hydrophobic pore-blocking or damp proofing admixtures, can slightly improve the chemical resistance of concrete to certain chemicals such as formic acid (Aldred 1988). However, many integral water-repellents offer little to no improvement; therefore tests should be performed to determine the effectiveness of particular admixtures. Admixtures containing chloride should not be used for reinforced concrete. Corrosion inhibitors (ASTM C1582) reduce chloride-inducedsteel corrosion. (See “Corrosion of Reinforcement” under “Design Considerations.”) Alkali-silica reactivity inhibitors, such as lithium nitrate, can be considered when potentially reactive aggregate is used and when alkali solutions will be in contact with concrete.
1.1 SCOPE OF THE STUDY
The study will cover the qualitative and quantitative analysis that is involved in the impact of latex on modified concrete bricks.
1.2 OBJECTIVES OF THE STUDY
The present study has been designed to evaluate the impact of latex on modified concrete bricks.
