本文關(guān)鍵詞： RCC 直接鋪筑允許時(shí)間 初凝時(shí)間 抗剪試驗(yàn) 吸水動(dòng)力法 掃描電鏡　出處：《浙江大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：由于碾壓混凝土(RCC)分層碾壓施工,故其層面出現(xiàn)薄弱環(huán)節(jié)的幾率比常規(guī)混凝土要大。已有試驗(yàn)結(jié)果表明,隨著層面間隔時(shí)間(從下層RCC拌合物加水開始,一直到上層RCC澆筑完成所歷經(jīng)的時(shí)間)的延長,抗剪斷強(qiáng)度逐漸降低。因此,研究RCC層間結(jié)合質(zhì)量的問題顯得尤為必要。為模擬施工現(xiàn)場(chǎng)分層碾壓鋪筑RCC的振動(dòng)效果,在實(shí)驗(yàn)室中,當(dāng)試件加壓振動(dòng)成型后,每間隔1h對(duì)相應(yīng)砂漿試塊(用于初凝時(shí)間試驗(yàn))和RCC試塊(用于抗剪試驗(yàn))無壓重?cái)_動(dòng)一次,擾動(dòng)持續(xù)時(shí)間分別為4s、8s、12s(以下簡(jiǎn)稱擾動(dòng)),并以無擾動(dòng)(加壓振動(dòng)成型后不做任何處理)砂漿試塊和RCC試塊做參照。本文首先針對(duì)RCC的初凝時(shí)間進(jìn)行了研究。通過設(shè)計(jì)三種不同的配合比,并改變材料溫度、減水劑摻量和擾動(dòng)條件,從RCC膠凝材料微觀機(jī)理的角度,對(duì)RCC的凝結(jié)時(shí)間試驗(yàn)結(jié)果進(jìn)行了分析。結(jié)果表明,澆筑時(shí)的材料溫度對(duì)初凝時(shí)間的影響較小。含緩凝成分的減水劑摻量對(duì)RCC初凝時(shí)間的延長作用顯著。擾動(dòng)(每間隔1h對(duì)相應(yīng)砂漿試塊無壓重?cái)_動(dòng)一次,擾動(dòng)持續(xù)時(shí)間分別為4s、8s、12s)對(duì)RCC初凝時(shí)間有顯著的延長作用。擾動(dòng)的持續(xù)時(shí)間越長,初凝時(shí)間延后越多,但延后的值不大。若以RCC層間抗剪強(qiáng)度不低于本體(下層混凝土鋪筑完成后立即鋪筑上層混凝土的RCC)抗剪強(qiáng)度的85%為控制標(biāo)準(zhǔn)來推求RCC直接鋪筑允許的層間間隔時(shí)間(以下簡(jiǎn)稱直接鋪筑允許時(shí)間),試驗(yàn)結(jié)果表明,無擾動(dòng)與受擾動(dòng)情況下的直接鋪筑允許時(shí)間有較大差異,而不同擾動(dòng)持續(xù)時(shí)間(每間隔1h對(duì)相應(yīng)RCC試塊無壓重?cái)_動(dòng)一次,擾動(dòng)持續(xù)時(shí)間分別為4s、8s、12s)的RCC之間的直接鋪筑允許時(shí)間差異較�。恢苯愉佒试S時(shí)間控制值隨著擾動(dòng)持續(xù)時(shí)間的增加而有所增加。吸水動(dòng)力法實(shí)驗(yàn)結(jié)果表明,施工擾動(dòng)、層間間隔時(shí)間延長會(huì)使RCC重量吸水率增加,使其平均孔徑增加,掃描電鏡實(shí)驗(yàn)結(jié)果佐證了吸水動(dòng)力法的實(shí)驗(yàn)結(jié)果。
[Abstract]:Because of the layered roller compaction construction of RCC, the probability of weak link in the layer of RCC is higher than that in the conventional concrete. The experimental results show that with the interval between the layers (starting with adding water to the lower layer of RCC mixture), The shearing strength decreases gradually with the prolongation of the time to the completion of RCC pouring in the upper layer. Therefore, it is necessary to study the quality of interlayer bonding of RCC. In order to simulate the vibration effect of layered compaction RCC in construction site, In the laboratory, the corresponding mortar samples (for initial setting time test) and RCC test blocks (for shear tests) have no pressure and weight disturbance once every 1 hour after the specimen is formed by pressurized vibration. The duration of the disturbance is 4 sg / 8 sL / 12s (hereinafter referred to as disturbance), and compared with the undisturbed mortar sample and RCC sample. The initial setting time of RCC is studied in this paper, and the results are as follows: (1) in this paper, the initial setting time of RCC is studied. For three different proportions, At the same time, the setting time test results of RCC cementitious materials are analyzed from the point of view of the microscopic mechanism of RCC cementitious materials by changing the material temperature, water reducer content and disturbance conditions. The results show that, The material temperature has little effect on the initial setting time. The content of water reducer with retarding component has a significant effect on prolonging the initial setting time of RCC. The duration of disturbance was 4sm ~ 8sm ~ (12 s). The longer the duration of disturbance was, the longer the initial setting time was, and the longer the initial setting time was, the longer the initial setting time was, and the longer the disturbance duration was, the longer the initial setting time was. If the shear strength of the RCC layer is not lower than that of the main body (RCCs of the upper layer concrete immediately after the completion of the lower concrete paving) as the control standard, the allowable interval between the layers of the RCC can be obtained by means of the control standard. Time (hereinafter referred to as the allowable time for direct paving), the test results show that, The allowable time of direct paving under the condition of no disturbance and disturbance is quite different, and the duration of different disturbance (one time per 1 hour interval to the corresponding RCC sample without pressure-weight disturbance), The difference of allowable time of direct paving between RCC with disturbance duration of 4 s-1 / 8 s-1 / 12s is small, and the control value of direct paving allowable time increases with the increase of disturbance duration. The experimental results of hydrodynamic method show that the construction disturbance is disturbed. The increase of interlaminar interval will increase the weight water absorption rate of RCC and increase its average pore size. The results of SEM experiments confirm the experimental results of hydrodynamic method.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TV544.921

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