PSI - Issue 64

Nathália Andrade da Silva et al. / Procedia Structural Integrity 64 (2024) 1460–1467 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Background and introduction The Teaching and Research Center for Low Environmental Impact Materials and Technologies in Sustainable Construction (NUMATS) is one of the Brazilian excellence laboratories. Its main goal is the formation of high qualified researchers for acting in the fields of materials, structures and sustainable construction technologies. One of the focus of NUMATS is to develop and propose solutions using bio-based building materials trough experimental and numerical researches. In this context, vegetable plant based materials such as sisal, jute, curaua, sugar cane bagasse, rice husk, bamboo, and wood shavings are widely studied as reinforcement of cementitious composites (Fidelis, 2014; Mendonça, 2018), ashes for cement partial replacement in concrete (Vieira, 2018; Gonçalves, 2022), for bio-concrete production (da Gloria, 2015; Andreola, 2017; Silva, 2019; Sá, 2022; Siqueira et al., 2023). This paper records and discusses the main researches on lightweight bamboo bio-concretes, from processing of the raw materials, mix design, behavior at fresh and hardened state, to greenhouse gas emissions.

2. Bamboo Bio-concretes 2.1. Bamboo bio-aggregates - Processing and treatment

Bamboo-derived aggregates display a broad range of characteristics, which are shaped by variables such as the bamboo species, culm age, and cultivation location. The apparent density of this bio-aggregate type typically ranges from 530 to 590 kg/m³, with water absorption levels spanning from 35% to 110%, and moisture content varying between 10% and 12%, as detailed in Table 1. Furthermore, the bio-aggregates dimensions and form are influenced by the crushing process.

Table 1. Bamboo bio-aggregates properties.

Apparent density (kg/m³)

Water absorption (%)

Moisture content (%)

Author

Andreola (2017)

580 530 580 590 580 580

109.14

11.01 10.18 12.28 10.00

Silva (2019) Lima (2020)

82.00 80.00 81.00 70.00 57.43

Andreola (2021)

Sá (2022)

- -

Siqueira et al. (2023)

The production of bio-aggregates relies on achieving the intended particle size for bio-concrete production. The process generally involves four main stages: 1. Cutting - Initially, the bamboo culm length is reduced by cutting (between 50 and 250 mm) before insertion into the crusher; 2. Crushing - The reduced bamboo culm is crushed until three times to reach the desired particle size for fine or coarse bio-aggregates. Numerous techniques exist for grinding bio-aggregates that impact on the size and morphology of the resulting particles. For instance, Andreola (2017), Silva (2019), Lima (2020) e Andreola (2021) employed an industrial crusher to initially reduce the bamboo culm to particle size comparable to conventional coarse aggregate, followed by using a knife mill to achieve the desired particle size akin to fine aggregates (Fig. 1b). According to Silva (2019), aggregates produced through this process can be categorized as elongated sub-angular aggregates with an average angularity index of 4016.2 and a 2D shape value of 11.71 (Fig. 1a). On the other hand, Sá (2022) and Siqueira et al. (2023) employed a crusher projected with a reduced tooth opening. This resulted in enhanced speed and efficiency of the process while producing particles varying from elongated to cubic in shape (Fig. 1b).