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Scarcity in the construction aggregates necessitated the use of suitable alternative materials such as recycled aggregates. However, the higher porosity of recycled aggregates due to the presence of adhered mortar affects its quality resulting in limited utilization. The purpose of this paper is to investigate the use of Bacillus subtilis to enhance the properties of the recycled coarse aggregate (RCA). The strains of the bacterial species were collected from the Gene bank, Chandigarh, and cultured to 105 cells/ml to treat the RCA.

The concrete mixtures are prepared with 0%, 50% and 100% of treated and untreated RCA by mortar mixing approach. The concrete specimens are tested for compressive strength, split tensile strength, flexural strength and elastic modulus at 7, 14 and 28 days, respectively.

Microbial treatment to RCAs increased the weight of the aggregate and decreased the water absorption of the aggregates. The optimal replacement of RCA was observed to be 50% and the strength of the concrete with 50% of treated RCA was comparable to the normal aggregate concrete. The CaCO3 precipitation by bacterial species fills the pores on the RCA and thus increasing the strength of the concrete.

The originality of the research is to produce concrete with waste recycled aggregate treated by bacteria to overcome the problem of scarcity in construction materials.

Dependence on access to European markets through subcontracting relationships with European firms has exposed subcontracting clothing and textile producers in less developed economies to the vagaries of international market competition. This paper aims to examine the problems that such exposure creates and the requirements for developing marketing activities through the concept of the alliance life cycle as a viable solution for a sample of Tunisian clothing and textile firms.

The inductive reasoning of this research was implemented through qualitative research based on a range of tools derived from a case study and a dual ethnographic approach.

The main results showed that life cycle stages of the subcontracting firms reflected Schumpeter's creation and destruction cycle of innovation. Therefore, subcontracting firms could learn from their activities with their business customers so that they developed marketing competences in innovative processes. The findings also demonstrated that some of the firms in the Tunisian clothing and textile industries were more successful than others.

This research focused mainly on subcontracting alliances with implications for future study of other alliances for different industries.

The life cycle approach could be of great interest to subcontracting managers in the post Multi Fibre Arrangement era. This approach is relevant mainly for decision makers in providing them with a framework within which they might optimise their marketing strategies and their implementations.

The research originality resides in its Schumpeterian perspective in considering business‐to‐business relationships. The value of the paper is to focus on the evolutionary aspects of relationships between contractors and subcontractors and the patterns of the marketing development within these relationships.