养护方式与水胶比对粉煤灰混凝土抗碳化性能的影响

发布时间：2018-04-04 20:06

本文选题：粉煤灰　切入点：混凝土　出处：《燕山大学》2013年硕士论文

【摘要】：粉煤灰作为混凝土中应用广泛的矿物掺合料，可以减少混凝土中水泥用量，提高经济效益，而且改善了混凝土性能，但粉煤灰的使用会降低混凝土中碱储备量，劣化混凝土抗碳化耐久性能。由于粉煤灰早期水化活性较低，与普通混凝土相比，粉煤灰混凝土抗碳化性能对养护条件更为敏感。基于此，本文以粉煤灰混凝土为研究对象，采用加速碳化试验方法，对比研究了不同养护条件下（标准养护28d、自然养护7d、自然养护3d）、不同水胶比（0.36、0.43、0.50）、不同粉煤灰掺量（等量取代水泥0%、20%、40%、60%）时混凝土的抗碳化性能。研究结果表明：水胶比是影响粉煤灰混凝土抗碳化性能的重要因素，与粉煤灰掺量共同影响混凝土抗碳化耐久性能，随着水胶比增大，碳化深度增加幅度明显提高。粉煤灰混凝土的抗碳化性能受养护方式的影响显著，与自然养护3d和自然养护7d相比，标准养护28d的粉煤灰混凝土，抗碳化耐久性能优异。随着粉煤灰掺量增加，养护方式对粉煤灰混凝土抗碳化性能影响的差异性减小。以保障混凝土碳化耐久性为前提，根据粉煤灰掺量、水胶比与养护方式对混凝土碳化性能的影响规律，建立了不同水胶比对应的粉煤灰临界掺量的数学模型ΦFA=174.8280.9W/B。根据该模型，在给定的水胶比条件下能计算出确保混凝土碳化耐久性的粉煤灰临界掺量。
[Abstract]:Fly ash, as a mineral admixture widely used in concrete, can reduce cement content in concrete, increase economic benefit and improve concrete performance, but the use of fly ash will reduce alkali reserve in concrete.Deterioration of concrete carbonization durability.The carbonation resistance of fly ash concrete is more sensitive to curing conditions than ordinary concrete because of its low hydration activity in early stage.Based on this, this paper takes fly ash concrete as the research object and adopts accelerated carbonization test method.The carbonation resistance of concrete under different curing conditions (standard curing 28 days, natural curing 7 days, natural curing 3 days), different water / binder ratio 0.36 ~ 0.43 ~ 0.50% and different fly ash content (replacing cement 020 ~ 20 ~ 40 ~ (60)) were studied.The results show that the water-binder ratio is an important factor affecting the carbonation resistance of fly ash concrete, and the carbonation depth increases obviously with the increase of water-binder ratio.The carbonation resistance of fly ash concrete is obviously affected by the curing mode. Compared with natural curing for 3 days and natural curing for 7 days, the carbonation resistance of fly ash concrete with standard curing for 28 days is better than that of natural curing for 3 days and natural curing for 7 days.With the increase of fly ash content, the difference between curing mode and carbonation resistance of fly ash concrete decreases.On the premise of ensuring the durability of concrete carbonization, according to the influence of fly ash content, water / binder ratio and curing mode on the carbonation performance of concrete, a mathematical model 桅 FAA (174.8280.9W/ B) corresponding to different water-binder ratio is established.According to the model, the critical content of fly ash to ensure the durability of concrete carbonation can be calculated under the given water-binder ratio.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.2

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