Concrete spacers play a critical role in maintaining the required concrete cover and ensuring the durability of reinforced concrete structures, particularly in tropical environments characterized by high humidity, elevated temperatures, and chloride exposure. This study presents a comparative evaluation of three commonly used concrete spacer systems: cement-based spacers, stone or brick spacers, and polymer-coated spacers. A qualitative, non-experimental research design was employed using data synthesized from established engineering literature, technical standards, and previous studies related to reinforced concrete durability and spacer performance. The evaluation was conducted through a Multi-Criteria Decision Analysis (MCDA) framework using eight performance criteria, namely compressive strength, water absorption, chloride penetration resistance, durability, bond compatibility, ease of installation, stability during concreting, and cost efficiency. Each criterion was assigned a corresponding weight based on its relevance to structural serviceability and durability in tropical conditions. Results of the weighted decision matrix indicated that cement-based spacers achieved the highest overall score of 4.655 due to their material compatibility with surrounding concrete, superior bond performance, and long-term durability. Polymer-coated spacers obtained a score of 3.655, demonstrating strong resistance to moisture penetration but exhibiting potential interfacial limitations under thermal and mechanical stresses. Stone or brick spacers recorded the lowest score of 1.750 because of their high porosity, irregular geometry, and poor durability performance. The findings suggest that cement-based spacers provide the most reliable overall performance for reinforced concrete structures exposed to aggressive tropical environmental conditions. This study highlights the importance of selecting appropriate spacer systems to enhance structural durability, minimize reinforcement corrosion, and improve long-term serviceability in tropical construction environments.
ALEJO et al. (Mon,) studied this question.