Book excerpt: Risk assessment is an important part of risk management in construction projects as it involves the identification, evaluation, and analysis of potential risk events, enabling project teams to properly mitigate them. To receive risk input from multiple stakeholders and aggregate them, different methodologies have been developed to support collaborative risk assessment. However, these systems do not ensure confidentiality in individual assessments, making it difficult for the stakeholders to provide their honest input. More problems such as lack of transparency and traceability occur as these systems are implemented in a centralized matter. Blockchain is an emergent decentralized digital technology that can provide solutions to such problems found in centralized systems. In this study, the methodology for collaborative risk assessment utilizing private data has been established based on the literature review of risk management tools and blockchain technology. A private permissioned blockchain network has been configured on Hyperledger Fabric which incorporates stakeholders for risk assessment, and smart contract algorithms have been developed to test out the functions explained in the methodology. Each step of the collaborative risk assessment process has been demonstrated on the prototype blockchain-based system. This research illustrates the benefits of adopting blockchain technology for collaborative risk assessment in construction projects and recommends future work based on its limitations