Preparation of a Rice Husk Composite and Effects of Cold Pressing on the Flexural Strength Properties

Abstract

The study of composites made from residual organic materials and polymeric resins, has a great projection due to the use of new raw materials and the good physical, mechanical and aesthetic characteristics these materials present in the construction industry. The manufacturing processes of these composites include the necessary pressure application to generate an efficiently compact material, where matrix and reinforcement bonding are efficient. This study defines how the compaction force influences the flexural strength of composites made from polyester resin as polymer matrix, and rice husk as reinforcement material. This is achieved by testing different series of specimens, made by applying different compaction forces in a cold process, to analyse the relationship between compaction and flexural strength. Specimens are made varying only the compaction force, from 2, 5, 8, 11, 14, and 17 tons. The results show that, when the compaction force increases, the flexural strength in the composites also increases, however, there is a pressure range where the flexural strength values are very close, conditioning the use of pressure in relation to the decrease in the specimen section.

Application of Carbon Nanofiber-Modified Concrete in Industrial Building Design

“…A total of two types of specimens were prepared for the test: a cube specimen of 100 mm × 100 mm × 100 mm and a prismatic specimen of 100 mm × 100 mm × 400 mm [ 8 , 9 ]. The preparation steps are as follows: ① preparation of carbon nanofiber dispersion: mix the water reducing agent into the water and stir evenly, add carbon nanofibers and half-part defoamer, stir at high speed for 2 minutes, add the remaining half-part defoamer, and manually stir at low speed for 5 minutes until there are no obvious bubbles in the dispersion; ② preparation of the concrete mixture: mix cement, sand, and stone evenly by the dry mixing method, then add nanocarbon fiber dispersion while stirring, and finally stir for 2 minutes; and ③ pouring and curing: after pouring and forming, cure under standard conditions for 28 d. The test mix ratios are shown in Table 3 .…”