本研究為輕質鋼筋混凝土梁之剪力行為研究，主要研究內容為在同樣皆為高強度混凝土的情況下，常重混凝土及輕質混凝土之間的行為影響，以及使用不同種類之纖維，如鋼纖維、PVA纖維添加至輕質混凝土中，試驗不同種類之纖維對輕質混凝土強度的影響。
因結構用輕質混凝土本身自重約為1840kgf/m3為常重混凝土的80%左右，可以有效降低因自重造成的彎矩，在橋樑使用方面可以有效地增加跨徑長度，其中正在興建的國道六號便是採用上部結構為輕質混凝土，下部結構為常重混凝土之設計，而使用輕質混凝土的好處不只自重可以降低，還具有防火性佳、隔熱性優、能有效隔音等優點，除此之外，輕質混凝土所使用的輕質粒料－陶粒，其主要來自於水庫淤泥燒製而成，能有效解決水庫淤泥造成的問題，屬於一種廢棄物再生的概念。
而輕質粒料又可分為人造輕質粒料及天然輕質粒料，人造輕質粒料為水庫淤泥燒結而成的陶粒、膨脹黏土等；天然輕質粒料則為浮石、泡沫火山岩等。而本實驗所使用的輕質粒料為水庫淤泥燒結而成的陶粒，比重為1.22；對比由荖濃溪新威大橋上游河段之砂石作為常重骨材，比重為2.8。
藉由控制水膠比及強塑劑，將輕質混凝土與常重混凝土的強度配置接近，再由同樣皆為高強度的B1高強度常重鋼筋混凝土梁、B2高強度輕質鋼筋混凝土梁、B3高強度輕質鋼纖維鋼筋混凝土梁、B4高強度輕質PVA纖維鋼筋混凝土梁、B5高強度半輕質鋼纖維鋼筋混凝土梁，五組不同的混凝土配比設計搭配三種不同鋼筋量，分別為3-#2(0.566%)、6-#2(1.133%)及12-#2(2.266%)，而每組不同配比的混凝土及鋼筋量製作2組15×15×53公分的梁，共計30支，來進行四點抗彎載重試驗。

This study focuses on the shear behavior of lightweight steel-reinforced concrete beams. The main research content includes investigating the behavioral differences between normal-weight concrete and lightweight concrete, both of which have high-strength characteristics. Additionally, the study examines the effects of using different types of fibers, such as steel fibers and PVA fibers, when added to lightweight concrete. Various types of fibers are tested to determine their impact on the strength of lightweight concrete.
The use of lightweight concrete in structural applications offers several advantages. Firstly, its lower self-weight, which is approximately 80% of normal-weight concrete, effectively reduces the bending moment. This allows for increased span lengths, making it beneficial for bridge construction. Moreover, lightweight concrete possesses excellent fire resistance, insulation properties, and effective soundproofing capabilities. Furthermore, the lightweight aggregates used in lightweight concrete, such as sintered clay made from reservoir silt, contribute to the concept of waste recycling by addressing the issue of reservoir silt disposal.
Lightweight aggregates can be categorized as artificial lightweight aggregates and natural lightweight aggregates. Artificial lightweight aggregates include sintered clay from reservoir silt and expanded clay, while natural lightweight aggregates consist of pumice and foamed volcanic rock. In this experiment, sintered clay from reservoir silt was used as the lightweight aggregate, with a specific gravity of 1.22. In comparison, sand and gravel from the Lao-Nongxi Xinwei Bridge upstream river section were used as the normal-weight aggregates, with a specific gravity of 2.8.
By controlling the water-cement ratio and superplasticizer, the strength of lightweight concrete can be adjusted to be similar to that of normal-weight concrete. Five different concrete mix designs, including B1 high-strength normal-weight steel-reinforced concrete beams, B2 high-strength lightweight steel-reinforced concrete beams, B3 high-strength lightweight steel fiber-reinforced concrete beams, B4 high-strength lightweight PVA fiber-reinforced concrete beams, and B5 high-strength semi-lightweight steel fiber-reinforced concrete beams, were prepared. Each mix design was combined with three different amounts of steel reinforcement: 3-#2 (0.566%), 6-#2 (1.133%), and 12-#2 (2.266%). Two sets of beams, each measuring 15×15×53 cm, were produced for each mix design, resulting in a total of 30 specimens. These specimens were then subjected to four-point bending tests to evaluate their load-carrying capacity.

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