Plant Growth and Water Purification of Porous Vegetation Concrete Formed of Blast Furnace Slag, Natural Jute Fiber and Styrene Butadiene Latex

Hwang-Hee Kim,Chan-Gi Park

doi:10.3390/su8040386

Abstract

The purpose of this study is to investigate porous vegetation concrete formed using the industrial by-products blast furnace slag powder and blast furnace slag aggregates. We investigated the void ratio, compressive strength, freeze–thaw resistance, plant growth and water purification properties using concretes containing these by-products, natural jute fiber and latex. The target performance was a compressive strength of ≥12 MPa, a void ratio of ≥25% and a residual compressive strength of ≥80% following 100 freeze–thaw cycles. Using these target performance metrics and test results for plant growth and water purification, an optimal mixing ratio was identified. The study characterized the physical and mechanical properties of the optimal mix, and found that the compressive strength decreased compared with the default mix, but that the void ratio and the freeze–thaw resistance increased. When latex was used, the compressive strength, void ratio and freeze–thaw resistance all improved, satisfying the target performance metrics. Vegetation growth tests showed that plant growth was more active when the blast furnace slag aggregate was used. Furthermore, the use of latex was also found to promote vegetation growth, which is attributed to the latex forming a film coating that suppresses leaching of toxic components from the cement. Water purification tests showed no so significant differences between different mixing ratios; however, a comparison of mixes with and without vegetation indicated improved water purification in terms of the total phosphorus content when vegetation had been allowed to grow.

Highlights

Ecosystem restoration has received growing attention in recent years, and there have been many and diverse investigations of the properties of concretes, including porous vegetation concrete [1,2,3,4]
This study investigated the addition of styrene butadiene (SB) latex and natural jute fiber, as well as the substitution of crushed aggregates with coarse blast furnace slag aggregates
Target performance metrics of the porous vegetation concrete were a compressive strength of ě12 MPa, a void ratio of ě25%, and residual compressive strength of ě80% following 100 freeze–thaw cycles

Summary

Introduction

Ecosystem restoration has received growing attention in recent years, and there have been many and diverse investigations of the properties of concretes, including porous vegetation concrete [1,2,3,4]. Plant growth is inhibited in concrete because of the limited space for rooting and sprouting, the low water permeability and retentivity, and the low nutrient content [5,6,7,8]. Porous vegetation concrete allows water and nutrients to be supplied, enabling plant growth [9,10,11]. A significant reduction in cement use would be an effective way to reduce CO2 global emissions [13]. The CO2 emissions associated with the production of 1 ton of cement are approximately 870 kg, and methods to reduce the use of cement in concrete are urgently required [5,13]. If cement could be replaced with blast furnace slag cement, it would be effective in reducing global CO2 emissions [13,14]

Objectives

Methods

Findings

Conclusion