發(fā)布時(shí)間：2018-07-09 22:23

  本文選題：多孔鋼渣 + 相變材料��； 參考：《西安建筑科技大學(xué)》2015年碩士論文

【摘要】：大體積混凝土結(jié)構(gòu)中由于內(nèi)外溫差較大而引起的溫度裂縫問題一直是土木工程質(zhì)量的頑癥之一。溫度裂縫一般都是貫穿裂縫,嚴(yán)重影響構(gòu)筑物的安全使用。目前對(duì)防治大體積混凝土溫度裂縫的研究中,主要是從內(nèi)因和外因兩個(gè)方面來考慮。本文從內(nèi)因考慮,將相變材料加入到大體積混凝土以降低其中心溫度和延緩中心溫度峰值的到來時(shí)間。相變儲(chǔ)能材料具有儲(chǔ)能密度大、吸放熱過程近似等溫的特點(diǎn),可以從內(nèi)部因素考慮降低大體積混凝土的中心溫度。本課題采用石蠟作為相變材料,多孔鋼渣作為載體吸附相變材料,采用真空吸附法制備多孔相變鋼渣骨料,分析和測試了多孔相變鋼渣骨料的熱性能。然后利用多孔相變鋼渣骨料制備多孔相變鋼渣混凝土,測試多孔相變鋼渣混凝土和多孔鋼渣混凝土的力學(xué)性能和熱性能,采用掃描電子顯微鏡(SEM)分析多孔鋼渣混凝土和多孔相變鋼渣混凝土的骨料-水泥石界面微觀形貌。最后,以實(shí)測工程中建筑物的基礎(chǔ)筏板為幾何模型建立有限元數(shù)值模型,采用有限元分析軟件MIDAS Civil模擬分析了多孔相變鋼渣大體積混凝土和多孔鋼渣大體積混凝土的溫度場以及中心溫度的差異。實(shí)測基礎(chǔ)筏板工程摻入礦物摻合料降低大體積混凝土的內(nèi)部溫度,對(duì)比分析了實(shí)測數(shù)據(jù)和多孔相變鋼渣大體積混凝土數(shù)值模擬結(jié)果。研究結(jié)果表明,多孔鋼渣對(duì)石蠟的質(zhì)量吸附率為7.75%,且吸附率會(huì)隨著粒徑的減小而增加,熱性能測試和分析表明多孔相變鋼渣骨料具有較好的儲(chǔ)能作用。溫升實(shí)驗(yàn)中多孔相變鋼渣混凝土的中心溫度峰值比普通鋼渣混凝土的中心溫度峰值降低了4.9℃,延遲了60min。多孔相變鋼渣混凝土的抗壓強(qiáng)度低于多孔鋼渣混凝土的抗壓強(qiáng)度。骨料-水泥石界面的微觀分析表明多孔相變鋼渣混凝土的界面不夠致密,有細(xì)小的縫隙。數(shù)值分析結(jié)果表明摻相變材料的控溫技術(shù)與摻礦物摻合料的控溫技術(shù)在降低大體積混凝土的溫度方面取得了相近的效果。
[Abstract]:The problem of temperature cracks in mass concrete structures caused by large internal and external temperature difference has been one of the persistent problems of civil engineering quality. Temperature cracks are generally through cracks, which seriously affect the safe use of structures. At present, the research on preventing and curing temperature cracks of mass concrete is mainly considered from two aspects: internal cause and external factor. In order to reduce the central temperature and delay the arrival time of the peak value of the center temperature, the phase change material is added to the mass concrete in terms of internal causes. The phase change energy storage material has the characteristics of high energy storage density and approximately isothermal heat absorption and exothermic process, so the central temperature of mass concrete can be reduced by considering the internal factors. In this paper, paraffin is used as phase change material, porous steel slag as carrier to adsorb phase change material, and vacuum adsorption method is used to prepare porous phase change steel slag aggregate. The thermal properties of porous phase change steel slag aggregate are analyzed and tested. Then the porous phase change steel slag concrete was prepared by porous phase change steel slag aggregate, and the mechanical and thermal properties of porous phase change steel slag concrete and porous steel slag concrete were tested. The interface morphology of porous steel slag concrete and porous phase change steel slag concrete was analyzed by scanning electron microscope (SEM). Finally, the finite element numerical model is established by taking the foundation raft of the building in the actual engineering as the geometric model. The temperature field and center temperature difference of porous phase change steel slag mass concrete and porous steel slag mass concrete are simulated by the finite element analysis software Midas Civil. The internal temperature of mass concrete was reduced by adding mineral admixture in the engineering of raft slab. The measured data and numerical simulation results of porous phase change steel slag mass concrete were compared and analyzed. The results show that the mass adsorption rate of porous steel slag for paraffin wax is 7.75 and the adsorption rate will increase with the decrease of particle size. The thermal performance test and analysis show that porous phase change steel slag aggregate has better energy storage function. In the experiment of temperature rise, the central temperature peak of porous phase change steel slag concrete is 4.9 鈩，

本文編號(hào)：2110894