低活化性屏蔽混凝土力學性質研究

A Study of Mechanical Properties of Low-Activated Shielding Concrete

鄭孟樺(MENG-HWA CHENG)

指導教授 ： 干裕成

朝陽科技大學/理工學院/營建工程系/碩士(2016年)

摘要

混凝土常做為核設施防幅射用途之屏蔽材料，而其強度並非為主要考量。因此，其配比常會添加一些材料，如氧化鋁粒料及碳化硼等，藉以增加其屏蔽效果。唯若此類混凝土結構產生裂縫，則影響範圍不只是構件本身強度，尚需考慮幅射外洩的潛伏危機；因此，必須對該混凝土材料的力學性質及破裂韌進行深入的瞭解，作為日後設計及評估之參考。
本研究主要研究含高純度氧化鋁粒料及碳化硼之低活化性高鋁混凝土(LAHAC)力學性質，並依添加不同含量之氧化鋁粒料，進行系統性之探討。本研究試驗，配比係採水泥量11%之碳化硼，及20%、40%、60%砂取代量之氧化鋁粒料，並與常重混凝土比較力學性質與工作性。藉由混凝土強度及破壞力學試驗，評估並比較LAHAC與普通混凝土之強度及破裂韌性。試驗結果顯示，LAHAC有高早期強度的特性，但抗壓強度及抗拉強度發展，會隨齡期增加而減小。另外，由於晶相轉化之影響，抗拉強度及破裂韌性，隨著氧化鋁粒料增加而有減少的趨勢。

關鍵字

力學性質 ； 碳化硼 ； 高鋁水泥 ； 屏蔽混凝土

並列摘要

Concrete is widely used as a shielding material of nuclear facilities for radiation protection. In addition to strength concern, it is often added some specific inclusions, such as alumina and B4C, to enhance the shielding capability. However, if the concrete cracks, it affects not only the strength of the construction but also the risk of radiation leakage. Thus, we must figure out the mechanical properties and fracture toughness of this type of concrete for future design and assessment.
The aim of this study is to analyze the mechanical properties and workability of low activation of high-alumina concrete (LAHAC) which consists of alumina oxide Al2O3 and boron carbide B4C. The concrete mixtures which consist of 11% B4C and 20%, 40% or 60% Al2O3 as fine aggregate replacement are designated. The strength and the fracture toughness of LAHAC and normal concrete were tested and compared. The results showed that LAHAC had high strength in the early stage, but the tensile strength and the compressive strength decreased with time duration. In addition, the tensile strength and the fracture toughness decreased as the alumina grains increased due to the conversion effect.

並列關鍵字

Mechanical Properties ； B4C ； High alumina cement ； Shielding Concrete

參考文獻

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