Nonconventional Ca(OH)2 Treatment of Bamboo for the Reinforcement of Cement Composites

Abstract

This study compares the structural and morphological changes in Guadua angustifolia Kunth (GAK) fiber prepared in three different ways (chips, barkless and crushed) when non-conventional alkaline treatment is applied. Moreover, it shows the improvement of mechanical properties of cement composites reinforced with these treated fibers. The three different preparations of Guadua were treated with a saturated solution of calcium hydroxide (5%) at 125 °C and 1.25 kPa for 3 h to remove non-cellulosic compounds. Then, their chemical, morphological, and structural properties were examined. The fibers exhibiting the higher delignification rate were selected to prepare cement composite boards, whose mechanical properties were successively compared with those of composites reinforced with untreated G. angustifolia fibers. The water/cement ratios of the cement mixed with the Ca(OH)2-treated and the untreated fibers were, respectively, around 0.3 and 0.25. The flexural strength and toughness of the two composites were evaluated after 7, 28, and 90 days of curing. The calcium hydroxide treatment showed higher efficiency in removing non-cellulosic materials when performed on crushed bamboo; moreover, the mechanical properties of the composites reinforced with the treated fibers were higher than those mixed with the untreated ones. After 90 days of curing, the flexural strength increased by around 40% and the toughness became three times higher (p < 0.05). The mechanical improvement by the Ca(OH)2 treatment of G. angustifolia fibers demonstrates its potential for the fabrication of cement composites.

Strength and microscale properties of bamboo fiber-reinforced concrete modified with natural rubber latex

“…The distribution of C-S-H decreases voids and boosts the specimen's strength. The rather porous textured features displayed in this matrix indicate a level of porosity typical of regular mixtures (Castillo-Lara et al, 2020;Sanchez-Echeverri et al, 2020;Zhang et al, 2020;Caballero-Jorna et al, 2021;Aisheh et al, 2022;Najm et al, 2022). Depending on the amount of latex in the mix, modified mixes on the other hand have displayed more compact characteristics.…”

A Sustainable Approach Using Beef and Pig Bone Waste as a Cement Replacement to Produce Concrete

“…Concurrently, studies have explored the incorporation of agricultural wastes, particularly the use of biomass ashes as pozzolanic agents in cement concrete or as alternative activators in geopolymer concrete, while preserving the fundamental properties required for construction materials [11,12]. Additionally, several authors have investigated the integration of natural fibers into cement to enhance its mechanical properties [13][14][15]. Recognizing cement's critical role in construction, substantial efforts have been made to develop more sustainable cements [16,17] or alternative materials for replacement.…”

“…In an effort to mitigate the environmental impact, various studies have proposed sustainable additions to concrete, aiming for ecofriendliness and sustainability. These include alternative concrete recycling methods and green concretes made from agricultural waste materials or compounds that require fewer non-renewable raw materials, such as sugarcane bagasse ash, rice husk ash, and palm oil fuel ash, which can reduce cement consumption while preserving the desired properties of cement [13,[20][21][22][23][24][25]. A significant benefit of these new alternatives in construction materials is the reduction in carbon dioxide emissions, extended durability, and decreased energy consumption [26].…”

Preparation and Performance of Cement Mortar Reinforced by Modified Bamboo Fibers

“…Therefore, bamboo fibers have the potential to be used in cement-based materials as a promising alternative reinforcement to synthetic polymer fiber and steel fiber. Since the pioneering work done by Pakotiprapha et al [ 6 ] and Ramaswaymy et al [ 7 ] in the 1980s, there have been a number of successful applications of bamboo fibers in cement-based materials [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. In general, by adding bamboo fibers (or treated bamboo fibers), the reinforced cement composites could demonstrate comparable compressive strength, improved flexural or tensile strength, and usually much higher fracture toughness.…”

“…Fiber surface treatment is one necessary and effective method to increase physical and chemical stability [ 24 , 25 ]. Some treatments boil fibers in water [ 26 ], alkaline substances, [ 9 , 12 , 14 , 27 ], or other chemicals [ 28 , 29 ] to reduce the amount of water-soluble substances in the fiber. Other treatments modify the fiber surface with sodium carbonate [ 30 ], silane coating [ 31 ], and polymer modification [ 10 , 15 , 32 ] to enhance mechanical properties and durability of natural fibers in cement materials.…”