ACI混凝土規範與緻密配比在防蝕耐久性設計之差異評估

Comparison of ACI Mixture Design Algorithm to HPC Desified Mixture Design Algorithm in the Anti-corrosion and Durability Design

本文旨在探討傳統ACI配比設計與緻密配比設計法內容，評估兩種配比法在耐久性設計之差異。內容包括傳統ACI混凝土配比的思維、黃氏緻密配比設計法的思路、新拌混凝土階段的耐久性考慮、混凝土耐久性設計指標及準則等。結果顯示，傳統ACI配比設計邏輯會因工作性或強度需求增加水泥漿量，然粗骨材用量不變下，因S/A下降，使骨材級配失去最佳化，導致降低混凝土的耐久性能；緻密配比設計邏輯是以骨材級配為最優先考量，在獲得最緻密級配下，使S/A維持不變，亦即各填充材用量比例不變，再考量工作性或強度所需漿量，以「物理緻密」、「化學強化」、「減水少漿」觀念，以增進混凝土性能，確保混凝土的耐久性及使用壽命。

The objective of this paper is to compare the difference between conventional ACI mixture design and Densified mixture design algorithm (DMDA) in the durability aspect. The content includes the durability consideration of both methods from mixture design, fresh stage, to service. Results of this study show that the conventional mixture design algorithm increases paste amount and reduce sand content in the consideration the increment on either workability or strength. Gradation of blend aggregate had lost its idea distribution. The durability of concrete hence decreases. The DMDA establish a priority by densifing gradation of aggregate. In any case, S/A ratio was kept constant. The paste content is determined by workability and strength but is kept as low as possible. Physical densified, chemical strengthen, and reduce paste content are the main factors keep in design concrete mixture for the durability. The purpose is to enhance concrete performance and durability during service life.