| 1. | Effects of water - cement ratio on plastic shrinkage cracking of concrete
水灰比对混凝土塑性收缩裂缝的影响 |
| 2. | 4 ) the effects of fly ash and silica fume on plastic shrinkage cracking were related to the actual w / b ratio of concrete mixture
对粉煤灰，这一水胶比界限约为0 . 36 ，对硅灰约为0 . 4 。 |
| 3. | The judge criterion of plastic shrinkage cracking for cement based material was studied through the testing of plastic tensile strength and plastic shrinkage capillary stress of cement mortar and concrete
摘要采用自行设计的塑性抗拉强度、塑性收缩开裂应力测定装置测试了水泥砂浆、混凝土塑性抗拉强度和塑性收缩开裂应力。 |
| 4. | The trends of plastic shrinkage cracking in concretes made with the same water or cement paste content per cubic meter are similar with the above case , but the critical w / c ratio is about 0 . 45 - 0 . 4 and 0 . 4 , respectively
2 ）在一定砂率范围内，较低和较高砂率对应的混凝土拌合物不易开裂，而中间某一临界砂率对应的混凝土拌合物开裂较大，这一临界砂率变化范围为36 - 43 % 。 |
| 5. | There was a borderline w / b ratio , above which concretes containing fly ash or silica fume were more sensitive to plastic shrinkage cracking than that of concretes without fly ash or silica fume , and below which fly ash or silica fume high performance concretes can restrain the plastic shrinkage cracking
6 ）在室内控制环境条件下，降低环境温度、风速以及提高相对湿度均可减少新拌混凝土水分蒸发速率，从而减少塑性收缩裂缝。相比之下，提高环境相对湿度对减少水分蒸发和裂缝更为明显。 |
| 6. | In the paper the effects of the made parameters , the main materials and environmental conditions on plastic shrinkage cracking were investigated . it can be concluded as following : 1 ) there was a critical w / c ratio of maximum plastic shrinkage cracking between lower and higher w / c ratio of concrete mixtures made with the same cement content per cubic meter , concretes with lower or higher w / c ratio being less prone to plastic shrinkage cracking and the w / c critical ratio critical of maximum plastic shrinkage cracking being about 0 . 5
本文研究了配制参数、主要原材料以及环境条件对新拌混凝土塑性收缩裂缝的影响，结果表明： 1 ）单方混凝土水泥用量一定时，较低水灰比和较高水灰比对应的混凝土拌合物不易开裂，而中间某一临界水灰比对应的混凝土拌合物开裂较严重，这一临界水灰比为0 . 5 ；单方混凝土水用量或水泥浆量一定时，混凝土拌合物的塑性开裂趋势与上述情况相似，但临界水灰比分别为0 . 45 - 0 . 4和0 . 4 。 |
| 7. | The proportion of plastic shrinkage cracking is rather high in early cracking . the plastic shrinkage cracking would effect construction appearance and promote the propagation of drying shrinkage cracking or other types cracking , but also provide a passage for aggressive agents penetrating and moving to the concrete mass
塑性收缩裂缝在早期裂缝中占有相当大的比重，其存在不仅影响工程外观，促使干燥收缩裂缝或其它形式裂缝的发展，而且还将为侵蚀性介质向混凝土基体渗透、迁移提供通道，对混凝土的耐久性造成严重影响。 |
| 8. | The results shows that the combined use of fibers and expansions was superior to the use of fibers or expansion agents alone in reducing the amounts of plastic shrinkage cracks and diminishing the size of cracks , and it improved the resistance to plastic shrinkage crack extremely
文章研究了聚丙烯纤维和膨胀剂复合对砂浆塑性收缩裂缝的影响，结果显示，纤维与膨胀剂复合，在减少塑性收缩裂缝数量和细化裂缝两个方面均优于纤维或膨胀剂的单独作用，砂浆抵抗塑性收缩开裂能力显著提高。 |
| 9. | 2 ) to a certainty of sand percentage , concretes with moderate critical sand percentage which changed in about 36 % - 43 % were more sensitive to plastic shrinkage cracking than concretes with lower or higher sand percentage . 3 ) concrete made with lower strength grading cement was more prone to plastic shrinkage cracking than that of concrete made with higher strength grading cement
4 ）粉煤灰和硅灰对混凝土塑性收缩裂缝的影响与拌合物的实际水胶比有关，存在一个水胶比界限，在此界限之上，掺入粉煤灰或硅灰的混凝土较易开裂，在此界限之下，粉煤灰或硅灰高性能混凝土对塑性收缩裂缝具有抑制作用。 |
