Earthquake Resistance of Adobe Reinforced by Low Cost Traditional Materials

Abstract

Adobe houses are expected to continue providing the housing needs of rural poor people because of their energy effi ciency, comfort, and cost effectiveness. Unfortunately traditional adobe constructions are very poor against earthquakes and cause signifi cant loss of life and property. Seismic defi ciencies of such structures are mainly due to brittleness and low strength of the blocks; low strength as well as poor bonding of mortar; and lack of structural integrity. Considering affordability, availability, environmental friendliness and easy construction, the current study adopts natural fi bers (straw, hemp and jute) and cementing materials (cement and gypsum) as reinforcing materials to improve the strength and ductility of adobe material. Straw improves the ductility of adobe block at the cost of compressive strength. Jute is the most effective among the selected fi bers to improve both the ductility and toughness of adobe block. Gypsum improves the strength of adobe block but not the ductility. Similarly, cement is effective for improving the mortar strength only. On the contrary, jute is effective for improving the mortar strength as well as coherence between block and mortar. Higher fl exibility, tensile strength and friction of jute might be the reason for its best performance.

Earthen construction materials: Assessing the feasibility of improving strength and deformability of compressed earth blocks using polypropylene fibers

“…The fibers prevented crack-face separation mainly through a stretching process, which provided an extra energy-absorbing capacity while also reducing the stress around the micro-cracked region surrounding the crack-tip [42]. The observed enhancement in ductility and flexibility of the reinforced blocks as observed in this research improves the capacity of blocks to store elastic energy providing some resistance to out-of-plane loads at the system/wall level [8,16,17].…”

“…Fiber-reinforced blocks can withstand higher stresses by absorbing high amounts of energy making them particularly important in earthquake prone regions [8]. It has been demonstrated that sisal [11,12], coconut fiber [13][14][15], straw [16], polyethylene [10], jute [17,18], are all feasible options for CEB reinforcement. Improvement in ductility is widely accepted as a key benefit of fiber reinforcement in soil-cement composites.…”

“…The first is a system level approach that uses structural reinforcement (steel rebar), reinforced concrete bond beams, roof to wall connections, and other established guidelines for unreinforced masonry practice. The second approach is improving block and mortar properties such as strength, ductility, toughness, and block-mortar bonding [17,21,22]. The study presented in this paper adopts the latter approach by evaluating the influence of polypropylene fibers at different weight fractions on the strength (compressive and 3-point bending), ductility, failure mode, and deformability at the block level.…”

Role of fiber inclusion in adobe masonry construction

“…The application of adobe materials faces several constraints due to their brittle behaviour, low tensile strength and deterioration when exposed to moisture. However, the properties of adobe can be improved by mechanical compaction, chemical stabilisation with cement, lime and bitumen, and fiber inclusions such as straw [3,6]. Chemical stabilisation can significantly improve strength and water resistance of adobe.…”

The Effects of Raw Rice Husk and Rice Husk Ash on the Strength and Durability of Adobe Bricks

“…Adobe construction is a type of earthen construction in which sun dried bricks are laid to form the walls of houses. Since soil is often freely available, this affordable construction is the method of choice for many low-income communities in developing countries [1,2]. For example in Sindh Province of Pakistan about 39% of all housing is adobe houses while the percentage in Peru is 60% and in India about 73% [3,4].…”