HLC-RAW快硬型水下不分散修补剂的研究

对HLC—RAW快硬型水下不分散修补剂配制的水泥基修补材料性能进行了研究。结果表明，HLC—RAW内掺取代水泥10％～15％配制的水泥基修补材料凝结时间在1~5h可控，水泥流失量仅为0．05％，水样的pH值仅为7．5，水中与空气中抗压强度比7d大于80％，28d大于90％，该材料的良好技术性能为水下修补工程质量提供了有效保证，适合潮差地段、水流较大或需要紧急投入运行的水下抢修工程应用。

OBSERVATIONS OF PEAK STRENGTH BEHAVIOR IN CSA CEMENT MORTARS

The purpose of this study was to assess the mechanical property performance behavior of calcium sulfoaluminate(CSA)cement mortar when cured at ambient laboratory temperature of~23℃(73°F)and constant 50%relative humidity for an extended period of time.Four CSA cement mortars were tested.Three CSA cement mortars contained equivalent mass amounts of calcium sulfate;whereas,the fourth mortar contained double the amount of calcium sulfate.The three CSA cement mortars containing constant mass amounts of calcium sulfate differed as the specific type of calcium sulfate varied across the three formulations-one mortar containing solely anhydrite,one mortar contained half anhydrite and half gypsum while the other mortar solely contained gypsum.The fourth mortar contained double the amount of calcium sulfate when compared with the others while having a 1/1 blend of anhydrite and gypsum.Specific mortars were either tested for direct tensile strength according to ASTM C307 or for compressive strength according to ASTM C109.All tested mortars displayed statistically significant strength loss trends versus time when cured at constant 50%relative humidity.Cement paste samples were analyzed with TGA/SDT and XRD in an effort to identify microstructure changes corresponding to observed strength loss.Cement paste analysis suggests strength loss within the tested CSA cement mortars occurred as a result of ettringite decomposition.

INFLUENCE OF LATEX POLYMER ADDITION ON THE BEHAVIOR OF MATERIALS CONTAINING CSA CEMENT CURED AT LOW HUMIDITY

The present study assesses the hydration behavior of polymer modified and non-polymer containing calcium sulfoaluminate(CSA)cement pastes containing minor phase tri-calcium aluminate(C3A)when cured at ambient laboratory temperature with 50%relative humidity.The particular CSA cement is unique as it offers two potential paths for ettringite formation.In the presence of sufficient calcium sulfate,these two potential paths stem from either hydration of yeelimite or hydration of tri-calcium aluminate.The study assesses the microstructural behavior of cement pastes utilizing powdered x-ray diffraction(XRD)and thermogravimetric analysis(TGA/SDT).Additionally,the study utilizes direct tensile strength testing according to ASTM C307,Standard Test Method for Tensile Strength of Chemical Resistant Mortar,Grouts and Monolithic Surfacings to quantify relationships between microstructural characteristics and mechanical property performance for representative mortars.The present study is significant as it illustrates differences in microstructural behavior for CSA cement materials with and without polymer cured at constant 50%relative humidity.The present study suggests ettringite decomposition occurs within non-polymer containing CSA cement paste samples cured at constant low humidity.The present study presents polymer modification as an effective means for mitigating ettringite decomposition and subsequent strength loss in materials containing CSA cement cured at constant 50%relative humidity and 23℃.

文昌A凹陷珠海组储层区域成岩作用特征及定量评价

运用砂岩铸体薄片、扫描电镜、图像分析、孔隙定量分析等资料,研究珠海组深部储层砂岩成岩作用,确定成岩作用横、纵向分布规律;计算成岩参数压实损失的孔隙度和压实率、胶结量、视溶蚀率和溶蚀量,分别对压实作用、胶结作用和溶蚀作用进行定量评价,确定区域成岩作用强度.结果表明:珠海组总体为中等—强压实.其中,凹陷西缘为弱胶结、中等溶蚀;凹陷中心以中等胶结、中等溶蚀为主;南断裂东段下降盘为中等—强溶蚀,珠海组一段和二段为中等—强胶结,珠海组三段为弱—中等胶结;南断裂中段下降盘珠海组一段和二段为中等胶结,珠海组三段为弱胶结,珠海组一段为中等近强溶蚀.