Constitutive models for fibre reinforced soil bricks

Abstract

In this paper, the physical, durability and mechanical properties of soil bricks reinforced with chicken feather fibres (CFF) and sugarcane bagasse fibres (SBF) were studied. The adopted optimum lengths of 15-mm of CFF and SBF were randomly distributed in the soil mix at 1%, 3%, 5%, 7%, 9% and 11% by weight. In total, 525 samples of cubic (350) and prismatic (175) soil samples were prepared for each fibre type and tested in accordance with the guidance in the British standards for bulk density, water absorption, compressive strength and tensile strength at 14, 28, 56, 90 and 180 days. With the addition of 7% CFF and 5% SBF, soil brick samples were found to be 98.8% and 78.7% stronger respectively in compression compared to the control mix. Based on the experimental results the stress-strain model describing the soil bricks response to compressive loading for each fibre type was obtained via regression analysis.This study contributes original data to the characterization of soil bricks and provides reference values that can be considered for design purposes. The soil bricks thus developed will contribute to the provision of affordable and sustainable housing construction across the world, particularly in developing countries.

The Compressive Strength of Unfired Clay Brick with Sugarcane Bagasse Fiber (SBF) and Bio-Enzyme Reinforcements

“…In Danso et al (2015), SBF was added and yielded a product with compressive strength ranging between 1.07 MPa-1.13 MPa. Similarly, Salih et al (2020) showed that adding SBF increased compressive strength and obtained values between 1.82 MPa-3.98 MPa.…”

“…Adding fiber to a clay mixture forms a bond, and this addition is responsible for compressive transmission in soil. This effect is called the fiber bridging mechanism (Salih et al, 2020). This can be seen in the SBF-containing samples, which had higher compressive strength ratings compared to the C and X samples.…”

“…The SBF was obtained near Depok, West Java, Indonesia, as it was readily available there in the form of waste. The SBF was sun-dried and cut into lengths of approximately 15 mm, the optimum length as defined by Salih et al (2020). The bio-enzyme was produced using five types of vegetables: cabbage (Brassica oleracea), cucumber (Cucumis sativus), cowpea (Vigna unguiculata), spinach (Spinacia oleracea), and water spinach (Ipomoea aquatica).…”

“…Previous studies related to unfired clay brick production have included added materials as reinforcements to create what is commonly known as reinforced brick. Some of the studies used natural plant fibers, including straw (Binici et al, 2005), sisal (Njau andPark, 2015), coir (Danso et al, 2015), and sugarcane (Saccharum officinarum) bagasse fiber (SBF) (Danso et al, 2015;Salih et al, 2020). The use of cement as an additive in clay brick is also common because of its mechanical strength, but it is less environmentally friendly given the high energy costs and CO2 emissions that accompany cement manufacturing (Zhang, 2013;Marcelino-Sadaba et al, 2017;Joglekar et al, 2018).…”

“…The addition of SBF to unfired clay brick improved compressive strength when the SBF was cut to an optimum length of 15 mm and comprised 5% of the total clay mixture. Generally, the compressive strength values ranged from 1.82 MPa-3.98 MPa (Salih et al, 2020). Another study was also conducted using SBF in which optimum compressive strength was obtained using 80 mm-long fibers that yielded ranges between 1.07 MPa-1.13 MPa (Danso et al, 2015).…”