High-Density Polyethylene (HDPE) and Polystyrene (PS) as Constituents in Creating Plastic Bricks

Abstract

INTRODUCTION

The invention of plastics is deemed as a remarkable breakthrough upon the existence of humankind, with its key properties that comprise of good durability and low weight. However, microorganisms are not able to decompose its molecules, and so, concern in increasing number of pollutants upon ocean, air, and land has raised awareness among people. With these in mind, the researchers attempted to develop lightweight and durable construction bricks out of waste from two types of plastics, High Density Polyethylene (HDPE) and Polystyrene (PS).

METHODS

Varying amounts of HDPE and PS are utilized to form three setups, namely, 100% HDPE, 100% PS, and 50% HDPE 50% PS. In order to melt, mold, and compress HDPE and PS, they were exposed to heat and chemicals, particularly acetone, respectively. The setups were subjected to tests of weight and durability -water absorption test and compressive test at Universal Testing Laboratory and Inspection, Inc. if it fulfilled the conditions of a standard brick. The distribution is normal using the skewness test. One-way ANOVA was used to determine if there is a significant mean weight difference between the three.

RESULTS

Having five trials for each set-up, the test for weight was as follows, setup 1, 100% HDPE, has a mean of 2629.2 g, setup 2, PS, has 1418.6 g, and setup 3, mixed HDPE and PS, has 1953.6 g. Lightweight construction bricks are considered more economical and can reduce the load by 30%-40%. It was then analyzed that there is the significant difference among the three set-ups at 5% level. On the other hand, the test for durability comprises of water absorption test and crushing strength test. A standard brick requires less than 7% water absorption to provide resistance from freezing. All the setups satisfied such condition, having only 0.8%, 3.2%, and 1.8% respectively. On the other hand, durability entails 70 MPa compressive strength to withstand and sustain compactness once exposed to high pressures. Then again, all of the setups exceeded the highest compressive strength and the values are 92 MPa, 105 MPa, and 95 MPa, respectively.

DISCUSSIONS

Upon the test for weight, it was declared that PS is the lightest, followed by mixed, and then HDPE. As all of the setups have fulfilled the Water Absorption Tes and exceeded the Compressive test, they are deemed as durable. Moreover, the set-up that was highly recommended was 100% PS as it has the lightest weight, appropriate water absorption rate, and highest compressive strength.