粉煤灰掺量对混凝土性能影响的试验研究

对粉煤灰掺量对混凝土性能的影响进行了试验研究。结果表明:粉煤灰能增大新拌混凝土的流动性,改善其和易性,能增加混凝土的凝结时间;粉煤灰改善混凝土后期强度的效果更明显,对早期强度有不利影响;粉煤灰能降低混凝土的电通量,提高混凝土的耐久性。     

粉煤灰掺量对高性能混凝土强度和工作性的影响

大量的工程实践表明 ,粉煤灰是配制高性能混凝土的重要组分之一 :增加粉煤灰掺量 ,能够明显改善混凝土的工作性 ,也利于配制泵送混凝土 ;高掺量粉煤灰混凝土的后期强度增长幅度较大     

粉煤灰掺量对高性能混凝土强度和工作性的影响

大量的工程实践表明，粉煤灰是配制高性能混凝土的重要组分之一：增加粉煤灰掺量，能够明显改善混凝土的工作性，也利于配制泵送混凝土；高掺量粉煤灰混凝土的后期强度增长幅度较大。     

双掺粉煤灰和钢渣对透水混凝土强度的影响

研究粉煤灰和钢渣作为胶结材单掺和双掺对透水混凝土强度的影响。结果发现:单掺粉煤灰和单掺钢渣时,随着掺量的增加,试样的早期强度均降低,但28天强度有所提高。当同时掺入粉煤灰和钢渣时(粉煤灰掺量为15%~20%,钢渣掺量为10%~15%),透水混凝土的28天抗压强度可提高5 MPa左右,这说明粉煤灰和钢渣的双掺对透水混凝土强度的提高起到协同增强的效应。     

粉煤灰、矿渣掺量对混凝土强度的影响

配制了一批不同龄期的C30矿渣粉煤灰混凝土,进行全面系统的试验研究与对比分析.研究了粉煤灰、矿渣和减水剂对混凝土强度性能的影响.试验结果表明:C30矿渣粉煤灰混凝土的矿渣最佳掺量为20%～30%;掺入减水剂后,更使混凝土的孔隙率减小、界面改善、泌水性降低并易于施工;同时,混凝土的抗压强度得到明显提高.     

水胶比和粉煤灰掺入量对混凝土抗压强度的影响

使用粉煤灰代替水泥用量对与环境和经济都有良好作用,粉煤灰混凝土近些年应用更加普遍.通过改变水胶比和粉煤灰掺入量,对高掺量粉煤灰的抗压强度进行研究,结果表明:往混凝土中掺入大量(70％—90％)粉煤灰时,混凝土的抗压强度会在长时间养护下不断增加,抗压强度会因为水胶比和粉煤灰掺量的增大而减小,但在实际应用中应综合考虑强度和流动性选择合适配合比的粉煤灰混凝土.     

废渣粉掺量对混凝土流动性、粘聚性、强度影响试验研究

将工业废渣粉代替部分水泥或骨料制备废渣粉混凝土是一种环保且经济的处理工业废渣粉的方案．研究了不同废渣粉掺量对混凝土流动性、粘聚性、抗压强度影响的作用机理,研究结果表明,废渣粉等体积置换骨料使混凝土的浆膜厚度显著提高,而浆膜厚度是混凝土流动性、粘聚性和抗压强度的关键影响因素之一;随着废渣粉置换量增加,混凝土流动性增强、粘聚性变差、28 d抗压强度先增加后降低;当废渣粉置换骨料量为10%时,混凝土28 d抗压强度达到最大,因此在实际工程中应用废渣粉时,要注意置换骨料量控制在10%左右,这样既能保证混凝土强度,又能实现废渣粉废物利用．     

粉煤灰及矿粉对水泥基注浆料性能的影响

以硅酸盐和硫铝酸盐复合水泥为基材制作水泥基注浆材料,分别讨论了不同类型、不同掺量的粉煤灰和矿粉对水泥基注浆材料的流动度、容重、膨胀率、抗压抗折强度的影响。结果表明:粉煤灰能有效地增加水泥基注浆料的流动度,当粉煤灰掺量低于20%时,可以提高注浆料的塑性膨胀率,当Ⅰ级粉煤灰掺量为20%或Ⅱ级粉煤灰掺量为15%时,3 h膨胀率最高达1%;粉煤灰对注浆料的早期强度不利,但可以增强其后期强度。矿粉可以改善其流动度,随着矿粉的增加,注浆料的容重和膨胀率均呈下降趋势;矿粉对注浆料的28 d强度无显著影响,其早期强度随着矿粉的增加而下降,当S75矿粉掺量高于7%或S95矿粉掺量高于11%时,抗压抗折强度不满足规范要求。     

椰壳纤维加筋红黏土强度特征

为改善红黏土的工程性质,使用椰壳纤维增强红黏土,并通过无侧限抗压强度试验和三轴压缩试验研究增强机理,探究椰壳纤维的长度和掺量对椰壳纤维加筋红黏土强度特征的影响。结果表明：椰壳纤维的掺入可以提高红黏土的强度和延性;椰壳纤维加筋土的无侧限抗压强度和抗剪强度随着纤维长度的增加先增大后减小,在纤维长度为5 cm时,达到最大值;当椰壳纤维掺量小于0.5%时,随着纤维掺量的增加,椰壳纤维加筋土的强度也随之增加,而当纤维掺量超过0.5%时,强度开始下降;当纤维掺量为0.5%、纤维长度为5 cm时,加筋效果最佳。     

浅谈如何保证混凝土施工质量

一、混凝土强度及主要影响因素 混凝土质量的主要指标之一是抗压强度,从混凝土强度表达式不难看出,混凝土抗压强度与混凝土用水水泥的强度成正比,按公式计算,当水灰比相等时,高标号水泥比低标号水泥配制出的混凝土抗压强度高许多.所以混凝土施工时切勿用错了水泥标号.另外,水灰比也与混凝土强度成正比,水灰比大,混凝土强度高,水灰比小,混凝土强度低,因此,当水灰比不变时,企图用增加水泥用量来提高混凝土强度是错误的,此时只能增大混凝土和易性,增大混凝土的收缩和变形.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

微薄的薪水,高尚的情操

现在,我们可以没有面包,没有钱,没有房子,没有车子……但我们唯独不能丢失的是高尚的情操,笃定的信念,还有,满满的希望!     

Virtual reality approach for 3D large model browsing on web site

Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching.