外文翻译--矿物掺合料的综合效应与强塑剂混合水泥浆的流动性(编辑修改稿)

外文翻译--矿物掺合料的综合效应与强塑剂混合水泥浆的流动性(编辑修改稿)内容摘要：

s. C2 cement containing natural pozzolan has an opposite behavior pared to C1 cement where its fluidity has a high efficiency with SP2 superplasticizer. This proves that the type of cement has a great control in the superplasticizer adsorption that leads to a judicious choice of the most effective couple C–SP to get a concrete with high workability. Fig. 3illustrates the difference between the flow times relative to 5 and 60 min with respect to superplasticizer dosage. This fluidity loss disappears with the increase of superplasticizer dosage especially for C1 cement which has a constant fluidity loss beyond % for SP2 superplasticizer and slightly less significant for SP1. Similar behavior was observed for C2 cement, where the fluidity loss decreases with the increase of SP2 dosage but remains higher for SP1. Cement with limestone powder (C1) exhibits a less fluidity loss which remains low for moderate dosages of both superplasticizers. On the other hand, cement with natural pozzolan (C2) requires a superplasticizer based on PRM (SP2) or a great dosage of SP1 to preserve its constant fluidity. . Saturation dosage From the curves illustrating the variation of flow time according to the dosage of the superplasticizer, the saturation dosage was determined for all couples of cement–superplasticizer and is presented inTable 3. It can be concluded that the saturation dosage of superplasticizer decreases according to the water–cement ratio. Superplasticizer SP2 presents a very good patibility with the two types of cement, contrary to SP1, which presents an almost total inpatibility. Limestone powder addition with C1 cement contributes to minimize some inpatibility cases with SP1, particularly for a replacement rate higher than 15%. The addition of limestone powder or natural pozzolan to the two types of cement has less sensibility on the saturation dosage with a little increase. . Superplasticizer type effect The choice of the superplasticizer type has a great importance to obtain the most stable fluidity of the paste. By using two superplasticizers。 SP1 and SP2 with C1 cement made with W/C ratio of . 4shows that the saturation dosage varies from to % for SP1 and SP2 respectively. Similarly, there was no loss of fluidity observed beyond the saturation dosage for SP2 which justifies its patibility with this type of cement. On the other hand,the results illustrated in Fig. 5confirm that C2 cement has an acceptable patibility with superplasticizer SP2 based on PRM,where the fluidity is slightly influenced by the dosage without significant loss beyond 1%. For superplasticizer SP1, the fluidity of the paste made with C2 cement is less important pared with that of C1 cement. It is to be noted that the fluidity obtained is reduced with the increase of the superplasticizer dosage. This indicates that high dosages of some superplasticizers may reduce the paste fluidity, confirming the negative effect of excessive superplasticizer content observed by several works[15,16]. In the same context,the fluidity loss is considerable for this superplasticizer which proves its inpatibility, particularly with C2 cement. . W/C ratio effect The cement paste fluidity is very affected by the amount of mixing water, for this reason the fluidity was tested for several W/C ratio. The results presented inTable 3show that superplasticizer SP1 remains inpatible for all W/C ratios, suggesting a notable loss of the fluidity after 1 h from the first contact with water. The fluidity of the mixture made with C1 cement and SP2 superplasticizer clearly improves at 5 min with the increase of W/C ratio as illustrated in Fig. 6. It is noted that for high W/C values, the flow time converges towards a unique value for various dosages of superplasticizer. Also,for a dosage higher than %, the flow time preserves nearly the same variation according to W/C ratio. From the results represented inFig. 7, the flow time of the mixture made with C2 cement and SP2 superplasticizer decreases with the increase of W/C ratio. When W/C ratio exceeds , the flow time values are close and remain constant for all superplasticizer . 6 and 7show that the fluidity of the cement paste made with C1–SP2 is more sensitive to the increase of the mixing water than that made with C2–SP2, where the fluidity varies only for low W/C ratio. . Mineral admixture effect When the replacement rate of the limestone powder increases from 10% to 15%, 20% and 25% in C1 cement, the fluidity of the paste keeps close values for all replacement rates and seems to be more influenced for low W/C ratio. On the other hand, the loss of fluidity appears much influenced by the content of limestone powder present in the cement. This loss increases remarkably for 15% replacement rate and low W/C ratio as it is illustrated in Fig. 8. Furthermore, the limestone powder has a benefic effect on the flow time and does not reveal any loss of fluidity for high W/C . 9illustrates the effect of the presence of the natural pozzolan on the fluidity of C2 cement. When the replacement rate increases from 15% to 20% and 25%, the fluidity of the paste at 5 min remains constant with a little improvement particularly for low W/C ratio. For W/C ratio, the addition of natural pozzolan leads to a considerable loss of fluidity. 4. Discussion The fluidity of the cement paste is related to the cement hydration and chemical interactions in the cement paste system and can be affected by the bination of cement type and chemical admixture, mineral admixture or water–cement ratio. This fluidity depends of the dispersing performances of superplasticizer which is proportional to its adsorption amount on the pound of the cement paste. [1] Prince W, Ladnef ME, Ait。