(1. 中南大學(xué) 資源與安全工程學(xué)院，長沙 410083；
2. 中南大學(xué) 深部金屬礦產(chǎn)開發(fā)與災(zāi)害控制湖南省重點試驗室，長沙 410083)
摘 要: 利用大桿徑分離式霍金森壓桿(SHPB)試驗裝置，對1、3、7、14、28 d這5組齡期下的混凝土進(jìn)行沖擊壓縮試驗，研究早齡期混凝土(C20)在不同沖擊條件下的力學(xué)特性。結(jié)果表明：齡期7 d以前，各齡期50%臨界入射能的沖擊有助于提高混凝土的強度和彈性模量；齡期7 d以后，無論是75%還是50%臨界入射能的沖擊，都會使混凝土的強度和彈性模量降低；在單次沖擊條件下，混凝土的變形能力和單位體積吸收能與齡期呈對數(shù)關(guān)系增長；在多個齡期沖擊條件下，混凝土的變形能力和單位體積吸收能都受到不同程度的影響，其中單位體積吸收能下降了50%。
關(guān)鍵字: 混凝土；力學(xué)特性；早齡期；分離式霍普金森桿
（1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China;
2. Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines,
Central South University, Changsha 410083, China）
Abstract:In order to understand the mechanical properties of early age concrete(C20) under different loading conditions systematically, the impact compression tests of five early age concrete were conducted with a large diameter split Hopkinson pressure bar. The results show that, the dynamic strength and elastic modulus of concrete are improved under the impact level of 50% or 75% corresponding critical incident energy before age of 7 d, while they would decrease if concrete suffered any impact after age of 7 d. The growth trend of deformation capacity and unit volume absorption energy of concrete with age can be presented with a logarithmic function under single impact. While the deformation capacity and unit volume absorption energy of concrete are affected when the concrete suffers impact at multiple ages, and the later is even declined by 50%.
Key words: concrete; mechanical property; early age; Split Hopkinson pressure bar
