Tests of Fiber Cement Materials Containing Recycled Cellulose Fibers.

Tomasz Gorzelańczyk,Krzysztof Schabowicz,Mateusz Szymków

doi:10.3390/ma13122758

Tomasz Gorzelańczyk, Krzysztof Schabowicz + Show 1 more

Open Access

https://doi.org/10.3390/ma13122758

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Abstract

This paper presents the results of investigations into the effect of the use of recycled waste paper cellulose fibers on the properties of fiber cement boards subjected to contamination by moisture. Four series of fiber cement boards were tested. A reference fiber cement board manufactured without the use of recycled cellulose fibers constituted as one of the series. The other three series consisted of boards differing in their recycled cellulose fiber content-ranging from 10% to 50% of the total cellulose fiber content. Specimens of the fiber cement boards were subjected to contamination by moisture by storing them in water for 1–96 h. Subsequently, their basic physical and mechanical parameters, i.e., mass moisture content, absorbability, and modulus of rupture (MOR), were tested. Then, the specimens were investigated by means of acoustic emission during three-point bending. Artificial neural networks were employed to analyze the acoustic emission test results. The tests clearly showed the amount of recycled waste paper cellulose fibers and the length of storage in water to have an adverse effect on the boards, contributing to their degradation. This was reflected in the decrease of the acoustic emission (AE) events count recognized by the artificial neural networks, accompanying the rupture of fibers during the three-point bending of the specimens. In order to gain a more detailed insight into the changes taking place in the structure of the tested fiber cement boards, optical examinations were carried out by means of a scanning electron microscope. Interesting findings crucial for building practice were noted.

Highlights

In building practice, it is often observed that under the impact of weather conditions, e.g., temperature changes and excess moisture, the physical and mechanical properties of exterior wall cladding deteriorate and eventually, the latter, is damaged
The fiberscontained containedinin boards lower their modulus of rupture (MOR)
In the case of the boards with a 50% recycled cellulose fiber content, the decrease in MOR due to moisture buildup for 96 h reached 50%, while for the reference board it amounted to 45%;

Summary

Introduction

It is often observed that under the impact of weather conditions, e.g., temperature changes and excess moisture, the physical and mechanical properties of exterior wall cladding deteriorate and eventually, the latter, is damaged. The mass moisture content and the modulus of rupture (MOR) were tested since, according to standard [12], these are the principal parameters indicative of the fiber cement board’s resistance to weather conditions and its durability These are basic tests, which do not give an insight into the destructive changes taking place in the structure of the tested boards under the action of the above factors. The authors found that an assessment of the effect of many service factors contributing to structural damage to the tested fiber cement boards, based solely on the modulus of rupture (MOR), was inadequate [7,8,9,13,14] This time, using the acoustic emission method to examine the degeneration of the tested samples, the authors were able to describe the destructive changes in the structure of the tested boards on the basis of the mechanical parameters, and the acoustic phenomena occurring in such boards. In order to verify the results and to gain a better insight into the changes taking place in the structure of the boards, the latter was optically examined using a scanning electron microscope (SEM)

Survey of Literature

Tests of Principle Physical and Strength Properties

Testing by Means of Acoustic Emission and Artificial Neural Networks

Findings

Conclusions