Abstract

This paper intends to evaluate the influence of content of rice husk fiber and cementitious materials on mechanical properties and thermal conductivity of thermal insulation wallboards. Thermal insulation wallboard contained different mass of rice husk fiber was prepared when the weight of cement, fly ash, cellulose ether, naphthalene superplasticizer, and recycled concrete aggregates was equal. Scanning electron microscopy (SEM) shows the internal structure of the insulation wallboards is very dense. Compared to thermal conductivity of blank group (0.9600 W/m·°C), B2 (0.1997 W/m·°C) and C2 (0.1810 W/m·°C) measured by the DRCD-3030 intelligent thermal conductivity tester can meet certain engineering requirements. Average compressive strength, flexural strength, and thermal conductivity of wallboards decreases with content of rice husk fiber increasing when other materials mass are the same. Under the same conditions of curing time and rice husk content, average compressive and flexural strength increase with the increase of the amount of cementitious material.

Highlights

  • Concrete materials in human social and economic development are indispensable

  • (3) Recycled concrete aggregates: Waste concrete was made into fine aggregate with particle size of less than 3mm through the aggregate crusher in laboratory (Wenzhou construction and demolition waste, China), as shown in S1 Fig. The water absorption of recycled concrete aggregates was 15.19%. (4) Cellulose ether, naphthalene superplasticizer, and rice husk fiber were purchased from Wenzhou Jingheng Chemical Reagents Company, China

  • Compressive strength and flexural strength of the specimens in the same age decreasing with the increase of the amount for rice husk fiber when the content of cement, fly ash, concrete powder, cellulose ether, and naphthalene superplasticizer are same, as shown Figs 7 and 8. 7, 14, and 28d of average compressive strength for groups A1 ~ A4 were 6.3, 7.8, and 8.2Mpa, 2.8, 2.8, and 2.9Mpa, 1.9, 2.1, and 2.0Mpa, 1.3, 1.4, and 1.4Mpa, respectively (Fig 7)

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Summary

Introduction

Concrete materials in human social and economic development are indispensable. With the progress of society and people’s living standards continues to improve. To ensure high-quality aggregate supply more difficult, which will inevitably affect the construction and national economic development. Waste concrete make into recycled aggregates, replacing normal natural aggregates has become an important issue, and researched by scientists around the world [1–23]. The use of recycled concrete aggregate as a building material is gaining popularity in China’s construction materials. High-performance concrete, stub columns, and beams can be cast by recycled concrete aggregates, and have good mechanical properties according to literature reported [24–27]. Few studies have been conducted on the production of thermal insulation wallboards through recycled aggregates according to web of science index. Thermal insulation wallboards were prepared with recycled concrete aggregate and rice husk fiber. Materials with a thermal conductivity of less than 0.20 W/mÁC are usually called thermal insulation materials [28–30]. The results show B2 and C2 of specimens can meet the actual engineering of strength requirements

Experiments and methods
Experimental mix proportion design
Specimens preparation
Characterization
XRD pattern and micro-structure of the specimens
Conclusions
Full Text
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