问题 问答题 简答题

硅酸盐水泥熟料的主要矿物成分有哪些?各有何特性?

答案

参考答案:

硅碳盐水泥熟料的主要矿物有四种,即:

①硅酸三钙、②硅酸二钙、③铝酸三钙、④铝铝酸四钙,此外,还含有少量的游离氧化钙等。

四种矿物成分各具不同的特性,如:C3A放热速度最快,放热量也最大;其次是C3S、C4AF放热速度较慢,放热量C3S大于C4AF;放热速度和放热量最小的是C3S。四种单矿物的水化反应速度、干缩和耐腐蚀性的规律同水化放热量的规律基本相同。单矿物的强度C3S早强、后强都较高;C2S早强低,后强高;C3A和C4AF的强度均较低。但在水泥混合体中,C3A与C3S混合后,混合体的早强会比C3S单矿物的强度高。单矿物C4AF与C3S混合后,也有类似的规律。f-CaO因水化反应速度极慢,且水化时体积膨胀性大,如其含量多,会对硬化后的水泥石起破坏作用。

完形填空
Immediately I got up and dressed, I stuck my violin under my jacket and went out into the streets to try my    . I wandered about for an hour, looking for a likely     , feeling as though I were about to commit a crime. Then I      at last under a bridge near the station and decided to have a try.
I felt tense and     . It was the first time, after all. I drew the violin from under the jacket like a gun. It was here, in Southampton, with trains rattling overhead, that I was about to       myself. One moment I was part of the hurrying crowds, the next I stood apart, my back to the wall, my hat on the       before me, the violin under my chin.
The first notes I played were loud and raw, like a declaration of protest, then they settled down and began to run more _   and to stay more or less in tune. To my     ,I was neither arrested nor told to shut up. Indeed, nobody took any     at all. Then an old man, without stopping at all, dropped a penny into my       as though getting rid of some guilty evidence.
I worked the streets of Southampton for several days, gradually obtaining the truth of the       by trial and error. It was not a good thing, for instance, to let the hat fill up with money---the sight could      a kind-hearted man; nor was it wise to      it completely, which could also confuse him, giving him no hint as to where to      his money. Placing a couple of pennies in the hat to start the thing going soon became a       practice and I made sure, between tunes, to take off most of the earnings, but always leaving two      behind.
Old      were most generous, and so were women with children, shop girls and barmaids.  As for men, heavy drinkers were always willing listeners and so were big guys with muscles. But      a man with an expensive hat, briefcase or dog: respectable types were the least      of all.  Except for retired army officers, who would shout "Why aren't you     , young man?" and then would over-tip to cover up their confusion.
小题1:
A.violinB.artC.skillD.luck
小题2:
A.stationB.spot C.streetD.bridge
小题3:
A.playedB.wandered C.stopped D.sat
小题4:
A.nervous B.excited C.lostD.strange
小题5:
A.shameB.show C.damageD.declare
小题6:
A.wallB.bridgeC.pavement D.road
小题7:
A.smoothlyB.slowlyC.angrilyD.roughly
小题8:
A.excitement B.sorrowC.astonishmentD.surprise
小题9:
A.moneyB.pityC.noticeD.rest
小题10:
A.hatB.pocket C.hand D.bag
小题11:
A.peopleB.tradeC.performance D.music
小题12:
A.encourageB.helpC.supportD.discourage
小题13:
A.fillB.emptyC.tear D.hide
小题14:
A.makeB.getC.drop D.earn
小题15:
A.modernB.regularC.timelyD.economic
小题16:
A.penniesB.dollarsC.poundsD.euros
小题17:
A.workersB.teachersC.doctors D.ladies
小题18:
A.neverB.oftenC.alwaysD.sometimes
小题19:
A.generousB.comfortableC.handsomeD.selfish
小题20:
A.playingB.workingC.cheatingD.shopping
单项选择题