Title

Investigation on the resistivity of concrete with high density polyethylene (DHPE) as partial replacement for fine aggregates against sulfate attack

Date of Publication

2018

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Civil Engineering with Spec in Construction Technology & Management

College

Gokongwei College of Engineering

Department/Unit

Civil Engineering

Thesis Adviser

Richard M. De Jesus

Defense Panel Chair

Jason Maximino C. Ongpeng

Defense Panel Member

Ronaldo S. Gallardo
Maria Emilia P. Sevilla

Abstract/Summary

Sulfate attack poses as one of the threats in construction through the deterioration of the concrete material. Due to the limited studies that have been conducted regarding the matter, the problem is often deemed to be negligible. However, previous studies from other countries consider sulfate attack to be a serious complication in terms of construction. The formation of ettringite crystals lead to the deterioration of the mechanical properties of concrete, as well as the expansion of the cement paste.

To address the issue, partial substitution of high-density polyethylene (HDPE) as fine aggregates was investigated under the effects of sulfate attack for HDPE is considered resistant against certain chemicals, especially sodium sulfate. The mechanical properties of the first set of concrete specimens were tested. The second set was then exposed in a sodium sulfate solution with a concentration of 50 grams per liter for twenty-eight (28) days before testing its mechanical properties. The mortar bars were submerged in the same solution before assessing the length change and formation of ettringite crystals through scanning electron microscope (SEM).

Results show that the change in compressive strength is insignificant for increasing percentage substitution but a significant decrease of the splitting tensile and flexural strength for the concrete specimens. The mortar bars show increasing sulfate resistivity as the percentage of HDPE replacement increases. Also, the SEM testing procedure exhibits less ettringite formation with the increase HDPE present in the mortar bars by considering its interfacial transition zone (ITZ).

Thus, the partial substitution of HDPE as fine aggregates is beneficial in resisting sulfate attack. Moreover, 10% of the volume of fine aggregates replaced with HDPE is considered as the ideal percentage substitution in terms of volume.

Abstract Format

html

Language

English

Format

Print

Accession Number

TU21575

Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall

Physical Description

xv, 113 leaves : illustrations (some color) ; 30 cm.

Keywords

Concrete; High-density polyethylene

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