【正文】 n in this field. Concrete is known to have goodthermal properties and, in construction, it is often used to protect structural steel. The effect of high temperatures on structural steel is to reduce its load carrying capacity due to the loss of strength and stiffness with increasing temperature.Polymer adhesives used in construction lose their strength at much lower temperatures than steel, and therefore, when such an adhesive is used for anchoring reinforcement, its bond will be the most vulnerablemechanical property following exposure at elevated temperatures. The heat deflection temperature (HDT) is defined as the temperature or the range of temperatures at which polymeric materials change from a rigid, glasslike state to an elastomeric like state。 at 20℃the mixed material has a pot life of 30 all specimens, the adhesive was poured into the gap between seal and concrete from the top (see Fig. 1) and,in order to ensure a full bond, the specimens were vibrated. Adhesive was also cast in tubes (19mmdiameter x 38 mm long) for pression tests. All specimens were placed in preheated ovens, at varioustemperatures, and were kept there overnight, to ensure that a constant temperature was achieved thoughout the specimens. Electric type convection ovens were used for uniform temperature pullout specimens were tested, at room temperature,for bond strength in a specially manufactured test rig, shown in Fig. 3, which was mounted into a 1000 kN Universal testing machine and pulled from the top, whilethe bottom face of the cube, as cast, reacted against the top plate of the testrig. The slip was measured at the unloaded end of the bar with the help of a sensitive LVDT, capable of measuring slip up to t0 mm. Loadwas applied by manual control and an attempt was made to apply a constant rate of loading to each force and corresponding slip data were recorded in a data logging system at regular time steps [6]. 3. EXPERIMENTAL RESULTS Polyester resin groutFor the pullout specimens, conditioned at temperatures below 220℃, a splittingtype of failure was started at the bottom of the cube and, as the load was increased, they progressed to the sides of the cube and split the cube into two halves. For the specimens conditioned at temperatures above 220℃a pullout type of failure was observed, ., the bond between steel and resin failed, and there was no obvious cracking of the normalized bond stress versus end slip for a selection of the tested pullout specimens is shown in . The stress values have been normalized with respect to the average bond strength (24 MPa) of specimens exposed to laboratory temperature control room environment(at 20℃ The curve for one of these specimens,shown as a thicker line in the figure, indicates that the bond strength is achieved after a slip of about 2 ram, a value not dissimilar to those obtained for monolithicallycast reinforcement. The value of slip displacement at which the maximum bond strength is observed, increases with temperature for specimens exposed to temperatures higher than 105℃The polyester resin specimens tested in pression failed in shear with the failure surface inclined at 45 ℃to the horizontal. However, at temperatures of about 230℃ and above, the specimens crumbled under load, showing very small pressive strength. The inner texture of the specimen was crystalline dark brown, indicating that the resin had burned or evaporated, leaving behind just the filler residual bond and pressive strengths of polyester grout versus the temperature at which the specimens were conditioned are shown in Fig. 5. The residual bond/pressive strength is normalized with respect to the strength obtained for the control specimens conditioned at 20℃ Best fit parabolic curves are fittedto the the residual pressive and bond strengths increase with temperature up to about 100℃a temperature which is close to the HDT. For temperatures higher than about 100℃ the strength gradually decreases, and for temperatures higher than about 180℃ the normalized strength falls below one. However, the decline in the bond strength is less sharp than the corresponding decline in pressive strength. 4. DISCUSSIONThe splitting failure obtained in specimens conditioned at low temperatures is an indication that the actual residual grout to steel bond strength could reach higher strength levels, since such failure is totally dependent on the geometry of the specimen and the concrete tensilestrength rather than on the actual39。,ACI Mater. J. 89 (1) (1992) 90105.2. Tassios, T. P., 39。, Mater. Struct. 6 (1973)103105.4. Dritsos, S. and Pilakoutas, K., 39。Anchorage Zones39。Temperature effects on the bond of resin anchored reinforcement39。為測定鍵強(qiáng)，拉拔試驗(yàn)選擇了150毫米的方塊。分裂的立方體發(fā)生在樣品暴露于大約200℃以下,并且粘性在慢慢的提高。1 引言高分子膠粘劑被廣泛應(yīng)用于全世界各地的維修、重建地震受損建筑物及老化失性等。在某些應(yīng)用中，縮短起動欄預(yù)先鉆洞，然后用膠灌漿。許多對火焰和提高溫度對混凝土和鋼筋混凝土的影響的調(diào)查表明鍵性能會產(chǎn)生不利影響。高溫對結(jié)構(gòu)鋼的影響是減少承載能力，這是因?yàn)殡S著溫度的升高強(qiáng)度和剛度降低。在低于熱變形溫度約10℃以下，材料的彈性模量、抗壓強(qiáng)度、粘結(jié)強(qiáng)度、抗蠕變性、化學(xué)和輻射性開始改變。然而，由于膠粘劑和熱膨脹系數(shù)差異所產(chǎn)生的問題通常可以通過減少膠層厚度來解決。然而，高溫下高分子膠粘劑的性能取決于他們絕緣性、熱導(dǎo)率、溫度水平、 曝露的持續(xù)以及表明應(yīng)力的大小和方向。通過對這兩種化學(xué)粘合劑在不同溫度下的壓縮強(qiáng)度的研究確定是否兩者之間有關(guān)系。然而，大多數(shù)研究人員以“拔出測試”為出發(fā)點(diǎn)，這樣能夠確定鍵強(qiáng)，也能夠找到平均鍵強(qiáng)和高溫下相應(yīng)滑動之間的關(guān)系?；谶@個(gè)原因，并且為了實(shí)現(xiàn)更均勻分布，選3倍鋼筋直徑，即36毫米。在所有樣品中，從頂部把膠粘劑倒入鉛和混凝土之間的空隙（見圖1）。對試樣在室溫下進(jìn)行測試，粘結(jié)強(qiáng)度在一臺專門制造的測試，如圖3所示。每隔固定的時(shí)間，滑動的力量和相應(yīng)的數(shù)據(jù)由數(shù)據(jù)采集系統(tǒng)記錄[6]。測標(biāo)準(zhǔn)鍵強(qiáng)選擇拉出試驗(yàn)試樣如圖4所示。該滑位移，最大粘結(jié)強(qiáng)度，是觀察，對暴露在溫度高于105℃溫度的升高值標(biāo)本。剩余聚酯砂漿抗壓強(qiáng)度與在該標(biāo)本條件是在圖5所示的溫度。然而，粘結(jié)強(qiáng)度下降小于相應(yīng)的抗壓強(qiáng)度下降。聚酯和環(huán)氧樹脂漿液抗壓強(qiáng)度分別提高了到100℃和130℃的溫度。結(jié)果，對錨固長度，由于近表面膠粘劑削弱可能減少對整體行為毀滅性。另外，從這些實(shí)驗(yàn)得出非常有價(jià)值的信息是，灌漿強(qiáng)度10ss密切相關(guān)的是抗壓強(qiáng)度損失，這也反映了灌漿強(qiáng)度。熱損壞的水泥漿將崩列，而堅(jiān)實(shí)的物質(zhì)將提供更大的阻力來鉆探。作為一個(gè)粗略的結(jié)論，在實(shí)踐中鍵損壞，有可能是高分子膠粘劑剝離，較弱的材料的強(qiáng)度將完全喪