The expansion agents can only make up the shrinkage to some extent, and the compensation effects would be reduced when the retardener and fly - ash are used. the expansion agents are not panaceas to avoid the shrinkage cracking as expansion can also reduce the concrete soundness. under bad curing condition, the polypropylene fibrillated film fiber can improve concrete ' s anti - crarking property, while the nominal steels have very unobvious effects. to reduce the concrete shrinkage thus avoid the cracking, the former factors must all be taken into account in concrete proportion design to develop sound concrete
研究結果表明,水泥的品種和用量是影響混凝土收
縮值的主要因素之一,當混凝土中水泥用量超過470kg / m ~ 3時,混凝土的收
縮值超過400 10 ~ ( - 6 ) ,在約束狀態下存在高開裂風險;採用細砂使混凝土單位用水量顯著提高,收
縮值也大幅增加;優質粉煤灰總體上能抑制混凝土的收
縮,以超量方式摻入其抑制作用更加明顯,但粉煤灰混凝土早期的粘聚性較差,應注意養護,以免失水產生龜裂;早強減水劑和緩凝減水劑都會使混凝土收
縮值增加;膨脹劑只能補償混凝土部分收
縮,同時受緩凝劑和粉煤灰的抑制,而且膨脹使混凝土的體積安定性增加了不確定因素,膨脹劑不是解決混凝土收
縮裂
縫的良方。
The paper is based on the construction of the express - highway between yiyang and changde in hunan province, aiming at enhancing the serviceability of cement concrete pavement, probing into the structural assemblage of the cement concrete pavement, the roadway drainage system, contraction joint with the dowel bar and precaution of bumping at the end of the abutment. it presents some achievements of the research, including more reasonable structural assemblage and roadway drainage system, the method of setting dowelled bar in contraction joint, putting forward the concept of stage - transition from rigid to flexile behind abutment
本文以湖南省益陽至常德高速公路項目為依託,以提高水泥混凝土路面使用性能為目標,就水泥混凝土路面結構組合、路面排水系統、
縮縫設置傳力桿、橋頭跳車問題的防治等方面開展研究和工程實踐,取得了豐富的研究成果,如研究採用了更合理的路面結構組合,設置了較完善的路面排水系統,在國內高速公路上率先全面採用
縮縫加傳力桿技術,對所有橋涵構造物臺背全部採用剛柔過渡技術處理橋頭跳車問題等。
Some other defects in castings are well - defined cracks and hot tears that develop during solidification, under combination of stress concentration from uneven contraction and the metal ' s low strength at near - melting temperatures
鑄件內部的其它一些缺點是,凝固過程中,在不均勻收
縮造成的應力集中和接近熔點溫度下金屬的低強度的綜合作用下,出現的清晰裂
縫和熱撕裂。
Optimal analysis of slab thickness for prestressed cored slab jointless bridge
無伸
縮縫預應力空心板橋板厚優化分析研究
Furthermore, the mode of jointless bridge was compared with joint bridge in this paper
此外,還比較了整體式橋臺的無伸
縮縫橋與有伸
縮縫橋梁的模態差異。
We have 510 sets of flat knitting machine, 160 sets of dial looper, a set ofwns - 0. 5 - 1 - y oil - fired boiler, and a set of fabric drying machine. we can product sweaters of 3g - 16g
三針到十六針針織橫機510臺套口
縫合車160臺及
縮毛烘房整燙檢品包裝等配套的后處理流水線。
Dongli group haveinternational advanced modern equipments, such as germany single or double machine, doners spain rib knitting machine, japan horizontal machine, sartorius, computer embroidery machine, hongkong little dyeing machine, italy woolen cloth shrink machinet etc, complete equipments, refined devices
如意針織公司擁有具有國際先進水平的現代化設備,主要有德國單、雙面大園機,道尼爾絲西班牙羅紋機,日本橫機、
縫紉機,電腦繡花機,香港小浴比染色機,義大利呢毯預
縮機等,設備齊全、裝備精良。
The calculation results indicate that the outboard of drum walls fall in plastic yielding at the same time the rising cooling water reaches the height of that point and the yield region becomes narrower and narrower when it comes closer to the circumferential strake weldments, which explains the reason coke drums experience bulging and cracks occur in the weld seams portions of shell to shell after long in service
計算結果表明:塔壁外側在冷卻水面到達的瞬間進入塑性屈服,筒節中部塑性屈服區較大,當靠近焊
縫時塔壁的塑性變形區逐漸
縮小直至消失,塔壁塑性屈服區的分佈特點解釋了塔體長期使用后發生鼓凸變形及簡體與焊
縫連接處產生裂紋的原因。
The variations in trace element contents and ratios may hold up a mirror to the lake - level fluctuations and climatic changes, which, in turn, have exerted a direct and important effect on the sequence stratigraphic development. collectively, the reservoir rocks from the yanchang formation consist dominantly of the delta front subfacies subaqueous distributary channel and channel - mouth bar microfacies and delta plain subfacies subaerial distributary channel microfacies fine - grained feldspar sandstones and siltstones. the reservoir rocks have been subjected to three stages of diagenetic and porosity evolution : ( 1 ) the porosity reduction by the mechanical compaction and chemical pressure solution during the early diagenetic stage ; ( 2 ) the porosity increase by the dissolution during the a substage of the late diagenetic stage, and ( 3 ) the porosity reduction by the cementation and filling during the b substage of the late diagenetic stage
系統的儲層特徵研究表明,該區延長組儲層成因類型主要為三角洲前緣水下分流河道、河口砂壩及三角洲平原水上分流河道微相細粒長石砂巖、粉砂巖;儲層巖石經歷了壓實,膠結,溶蝕等成巖作用,歷經早成巖機械壓實和化學壓溶孔隙
縮小期、晚成巖a亞期溶蝕作用孔隙擴大期及晚成巖a亞期( b亞期)膠結充填孔隙
縮小期三個成巖-孔隙演化階段;儲層物性總體上具有較低孔滲、低孔滲的特點,孔隙類型主要為粒間溶孔、殘余粒間孔隙、粒內溶孔、晶間孔及晶間溶孔,裂
縫不發育,儲集巖排驅壓力和中值壓力較高,孔隙結構類型以細小孔-微孔隙,微細喉-微喉型為主。
There are three kinds of crack include of structure crack, diagenetic crack and synaeresis crack in this area
該區裂
縫主要有構造
縫、成巖
縫和收
縮縫三種類型。
Gas cylinders. refillable seamless steel tubes for compressed gas transport, of water capacity between 150 l and 3 000 l. design construction and testing
氣瓶.水容量在150l和3000l之間的壓
縮氣體傳輸用可再填充的無
縫鋼管.設計結構和試驗
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
縮裂
縫在早期裂
縫中佔有相當大的比重,其存在不僅影響工程外觀,促使乾燥收
縮裂
縫或其它形式裂
縫的發展,而且還將為侵蝕性介質向混凝土基體滲透、遷移提供通道,對混凝土的耐久性造成嚴重影響。
This thesis investigated and researched on non - loaded crack, especially those caused by thermal - shrink, and analyzed the thermal - shrink stress of beam, slab and continuous - wall, found that according data of civil and overseas offered thermal - shrink calculating formula without considering effect of factors, such as the cement quantity, using of aruhuesiru, aggregate size and quantity of sand, which made the result data smaller. in addition, there are not enough construct measure in code
本文對非荷載裂
縫,特別是溫度?收
縮裂
縫進行了調查研究,並對兩端或四周約束的梁、板和底部約束的地下連續墻進行了收
縮應力分析,發現國內外有關文獻給出的收
縮計算公式沒有考慮泵送商品混凝土的水泥用量、外加劑使用、骨料粒徑和砂用量等因素的影響,計算出的混凝土收
縮量往往偏小;另外, 《規范》中針對溫度?收
縮裂
縫的構造措施不足。
This paper aims at the seriousness of concrete structure crack and presents one of main cause is that concrete early - age ( especially autogenous shrinkage ) become large through the systems academic analysis
本文正是針對混凝土結構工程早期裂
縫的嚴重性,通過理論分析,指出目前混凝土早期收
縮(主要自收
縮)的變大是造成這種早期裂
縫的主要原因之一。
Through the implementing of kernel level file and cache mechanism at the client side, this newly proposed distributed network file system provides seamless network file access and reduces the performance decline caused by network transmission. utilizing the concept of logic block server, it provides the reliable data block storage and implements redundant storage capacity. utilizing the concept of the index server, it provide s the cost of the greatly for server and network during data access process and realizes the computing with balancing capacity
在客戶端通過實現內核級文件的調用和緩沖機制,實現了文件的無
縫網路存取,並減少由於網路傳輸帶來的性能下降的影響;利用邏輯塊服務器實現邏輯塊的冗餘存取,實現數據塊的安全存放;利用索引服務器進行負載均衡計算,實現資料存取的較低網路和服務器開銷;利用索引服務器實現服務器組的零管理,使該系統具有高效性、穩定性和可伸
縮性。
Claw - plate s shoes size tegulation uses synchronous automatic regulating device to made regulation accurate and quickly, and be able to prevent form producting pleat between claw chink
爪盤鞋碼大小調整縮放,連用同步式自動調整,調整準確快速,並可預防布縫間隙產生角。