Future trends

Throughout this chapter, most of the important aspects related to the topic, Biodegradable fiber-reinforced polymer composites for construction applications, have been cited—variables such as the characteristics of the soil, the processes of stabilization, type of fiber reinforcement, and environmental characterization. Currently this type of material has a limited use in the construction industry. Some of the factors that influence this limitation are the durability of these materials, their mechanical characteristics, and existing regulations and standards compared to other traditional construction solutions. Moreover, these aspects are the ones that should be addressed by future developments and research to improve their characteristics and enhance their use.

Although earth construction methods have a very long history, mainly used for housing, CSEB were first introduced in the 1950s. Since then their usage has seen a constant growth in developing and developed countries. During the last decades there has been an increasing interest in CEB, more specifically in compressed stabilized earth blocks CSEB.

In developed countries environmental concerns arise, pushing forward the use of these construction materials. There is a huge contrast between CSEB and conventional bricks not only in the energy consumed during the production process but also the carbon emissions. According to Morton (2008), CSEB brick creates 22 kg CO2/tonne, compared to common fired clay bricks 200 kg CO2/tonne, concrete blocks 143 kg CO2/tonne, and aerated concrete blocks 280—375 kg CO2/tonne, during production. This is nowadays one of the stronger points to promote the usage of earth architecture.

The production of cement and lime (commonly used as stabilizers) also have high energy demands. Hence during recent years, more and more manufacturers have been interested in producing unfired bricks and biomaterials and the need for a stabilizer has arisen to complies with all these requirements in order to produce a low embodied energy unfired brick.

However, the development of standards and specifications related not only to the earth construction methods, such as New Mexico Earth Building Material Code 2003, but to the blocks themselves (and the stabilization system) is still very limited. Among the regulations we found the Indian standards IS 15:1725—1982, the New Zealand Standards, 1998, Engineering design of earth buildings, and the

Spanish UNE 41410:2008 (although there is no harmonization of this standard through the UE). Standards are required to enhance the use of earth materials. These regulations give the manufacturers a legal framework on which to base their products and subsequently increase the use of CSEB. Some of the existing standards, such as the ASTM D1633, refer only to soil—cement stabilizing, putting aside the possibility of biostabilizers, such the biostabilizers mentioned in this chapter.

Durability is the main limitation for unfired bricks. Durability results as exposed in literature differ considerably from each other. More research is needed in this field to expand the use of CESB, while durability tests need to be standardized. Fibers, which are not used in fired bricks, can cooperate to bridge this problem. Natural fibers from local sources can play an important role here.

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