Selection of the Optimum Carrier for Manufacturing Water-Repellent Concrete and Durability Evaluation of Cement Mortar Using It

Chang Bok Yoon,Han Seung Lee

doi:10.3390/app10249097

Abstract

The purpose of this experiment was to complement the shortcomings of existing surface treatment methods and to implement water repellency inside concrete to prevent water penetration and improve the durability of concrete. Carriers to provide water repellency were fabricated using fly ash (FA), silica fume (SF), and natural zeolite which are used as admixtures for concrete. They were mixed with cement mortar, tested, and evaluated. The compressive strength of the water-repellent impregnated natural zeolite (ZWR) specimen was 83% of that of ordinary Portland cement (OPC), and its contact angle was found to be 124°. The water penetration test and chloride ion penetration test confirmed that the water absorption and total passing charge were reduced, while the porosity and pore size were improved. For the other specimens, except ZWR, water repellency was judged to be insufficient due to the low fixing ability for the water-repellent’s active ingredient. The results of evaluating the physical performance and durability of cement mortar for the selection of the optimum carrier revealed that powders other than ZWR are not suitable as a material for providing water repellency to concrete.

Highlights

Reinforced concrete structures exhibit degraded durability over time when exposed to various external environments such as chlorides, CO2, and water
Cracks in concrete and pores on the concrete surface serve as transport pathways for water and chlorides [1]
Technologies to improve the durability of the concrete surface layer by applying liquid-type water repellents to the concrete surface without forming a separate sheet protection layer were developed as methods to reduce water penetration, and they have been used in References [2,3,4,5]

Summary

Introduction

Reinforced concrete structures exhibit degraded durability over time when exposed to various external environments such as chlorides, CO2 , and water. Cracks in concrete and pores on the concrete surface serve as transport pathways for water and chlorides [1] To address these problems, technologies to improve the durability of the concrete surface layer by applying liquid-type water repellents to the concrete surface without forming a separate sheet protection layer were developed as methods to reduce water penetration, and they have been used in References [2,3,4,5]. Cost and time are required to repair or reconstruct the concrete’s surface To complement this shortcoming, if the water-repellent’s performance can be implemented inside the concrete, it is possible to prevent a reduction in the durability of concrete due to the water penetration despite the occurrence of cracks and deformation. If the water-repellent’s active ingredient is directly added to implement the

Methods

Results

Discussion

Conclusion