The experiment determined the fracture process and the parameter of the fracture properties of two different aggregate concrete and recorded the stable whole fracture curves of boulder concrete and crushed stone concrete separately , which are determined through three - point - bending method and wedge - split tensile method 測(cè)定了兩種粗骨料混凝土的斷裂過(guò)程及斷裂特征參數(shù),分別記錄了兩種試驗(yàn)方法測(cè)定的卵石混凝土和碎石混凝土的斷裂全曲線(xiàn)。
According to the recorded full process fracture curve , the paper calculated and compared the fracture toughness ( kic ) , the fracture energy ( gf ) and crack tip opening displacement ( ctod ) of the different strength grade boulder concrete and crushed stone concrete , it is found that the maximal load ( fmax ) and the fracture toughness ( kic ) of boulder concrete and crushed stone concrete increase when the strength of them increases , so does the fracture energy of boulder concrete , but the fracture energy of crushed stone concrete does n ' t obviously increase when it ' s strength increases . the crack tip opening displacement ( ctod ) of all specimens chang less when the strength of concrete increases , so it is concluded that the location of the axle in the ligament of the specimens is relatively stable 根據(jù)記錄的全曲線(xiàn),計(jì)算了不同強(qiáng)度等級(jí)的卵石混凝土、碎石混凝土的斷裂韌度k _ ( ic ) 、斷裂能g _ f以及裂縫的尖端開(kāi)口位移ctod ,比較了不同強(qiáng)度等級(jí)卵石混凝土及碎石混凝土的斷裂韌度k _ ( ic ) 、斷裂能g _ f以及裂縫的尖端開(kāi)口位移ctod的關(guān)系,發(fā)現(xiàn)卵石混凝土、碎石混凝土的荷載峰值fmax 、斷裂韌度k _ ( ic )隨強(qiáng)度增加而增加,卵石混凝土的斷裂能g _ f隨強(qiáng)度增加而呈增加趨勢(shì),碎石混凝土的斷裂能g _ f隨強(qiáng)度增加變化趨勢(shì)平直,增勢(shì)不明顯。
By using 5000kn pressure - bent testing machine , the specimens of boulder concrete and crushed stone concrete were tested through three - point - bending method and wedge - split tensile method , the scale division of the index dial of pressure - bent testing machine is larger , whereas the predicted test - load is lesser , so the velocity of exerted load is controlled through observing the reading of the multimeter which is connected with the collecting systerm in order to continuously exert test - load 本文使用5000kn壓彎實(shí)驗(yàn)機(jī),對(duì)不同強(qiáng)度等級(jí)的卵石混凝土和碎石混凝土試件分別進(jìn)行了三點(diǎn)彎曲試驗(yàn)和楔入劈拉試驗(yàn)。試驗(yàn)過(guò)程中,由于實(shí)驗(yàn)機(jī)噸位較大,而試驗(yàn)荷載預(yù)計(jì)較小,為了能夠有效地控制加載大小和加載速度,采用通過(guò)觀(guān)察與荷載傳感器相連的萬(wàn)用表讀數(shù)控制加載速度的方法,連續(xù)加載。