本文選題：自密實(shí) + 自養(yǎng)護(hù)　； 參考：《重慶大學(xué)》2016年碩士論文

【摘要】：近年來,鋼管混凝土不斷應(yīng)用在高層建筑和超高層建筑中,但是鋼管混凝土澆筑的質(zhì)量以及后期的養(yǎng)護(hù)一直是實(shí)際應(yīng)用中的盲點(diǎn)。自密實(shí)自養(yǎng)護(hù)混凝土的出現(xiàn)為解決混凝土的澆筑質(zhì)量和后期養(yǎng)護(hù)提供了一種新的思路。本文通過大量的試驗(yàn),研究了在自密實(shí)混凝土基礎(chǔ)上加入高吸水樹脂(SAP)來得到既能滿足自密實(shí)性能也能達(dá)到一定自養(yǎng)護(hù)效果的混凝土(SAP-SCC)。本文的試驗(yàn)中以SAP摻量和額外引水量倍數(shù)為兩個(gè)基本參量,研究了自密實(shí)混凝土在加入不同SAP摻量和不同額外引水量倍數(shù)后的力學(xué)性能變化規(guī)律、體積穩(wěn)定性變化規(guī)律和自養(yǎng)護(hù)效果評(píng)價(jià)。通過濕度擴(kuò)散理論建立了SAP釋水前后SAP-SCC內(nèi)部濕度場(chǎng)微分方程,為解釋SAP自養(yǎng)護(hù)機(jī)理提供了一定的理論依據(jù),也為定量分析SAP自養(yǎng)護(hù)提供一種思路。本文基于規(guī)范方法設(shè)計(jì)了SCC的配合比,在此基礎(chǔ)上利用Powers理論得到了理論SAP摻量和額外引水量,并進(jìn)行SAP-SCC試配。結(jié)果表明,完全滿足工作性和力學(xué)性能的要求。SAP-SCC力學(xué)試驗(yàn)結(jié)果表明,適當(dāng)?shù)腟AP摻量和額外引水量倍數(shù)不會(huì)使混凝土強(qiáng)度顯著下降,并且28d強(qiáng)度還略有提高。但是SAP摻量和額外引水量倍數(shù)都不宜過大,否則各齡期混凝土強(qiáng)度會(huì)顯著下降。本文中,SAP的最佳摻量為0.15%(占膠凝材料的百分比)左右,最佳的額外引水量為10~15倍(高吸水樹脂的質(zhì)量)左右。SAP-SCC體積穩(wěn)定性試驗(yàn)結(jié)果表明,SAP摻入SAP-SCC后會(huì)顯著減小混凝土的自由收縮和自收縮。SAP釋水前,試驗(yàn)組與空白基準(zhǔn)組之間的自由收縮和自收縮的變化趨勢(shì)和大小均基本相同;SAP釋水后,試驗(yàn)組與空白基準(zhǔn)組之間的收縮變形差距開始顯現(xiàn)。本文中,SAP摻量為0.15%左右,額外引水量為15倍左右時(shí),SAP-SCC的自由收縮和自收縮的減縮效果最佳。本文基于Fick第二定理,通過濕度擴(kuò)散定理和濕度守恒建立SAP-SCC在SAP釋水前后的濕度場(chǎng)微分方程,發(fā)現(xiàn)SAP釋水前后的微分方程具有相同形式,說明SAP釋水前后SAP-SCC內(nèi)部濕度場(chǎng)的擴(kuò)散規(guī)律相似。然后,通過毛細(xì)孔壓力理論,根據(jù)拉普拉斯方程和Kelvin方程建立了混凝土相對(duì)濕度與毛細(xì)孔表面張力之間的關(guān)系,并根據(jù)應(yīng)力-應(yīng)變關(guān)系建立了SAP-SCC內(nèi)部相對(duì)濕度與相對(duì)收縮之間的關(guān)系。SAP-SCC養(yǎng)護(hù)效果試驗(yàn)研究結(jié)果表明,無論是SAP摻量還是額外引水量對(duì)電阻率的影響都與電極埋入深度有關(guān),即SAP摻量和額外引水量對(duì)養(yǎng)護(hù)效果的影響是與混凝土內(nèi)部深度有關(guān)。在電極埋入深度小于3cm時(shí),合適的SAP摻量和額外引水量可以顯著改善混凝土內(nèi)部的濕度,從而減小混凝土的電阻率�？梢哉J(rèn)為深度小于3cm時(shí)SAP自養(yǎng)護(hù)效果明顯,深度大于3cm后,雖然有一定的自養(yǎng)護(hù)效果,但沒有深度小于3cm時(shí)效果明顯�；诖�,可以認(rèn)為,加入SAP和引入額外水分后,對(duì)混凝土內(nèi)部起到了一定的養(yǎng)護(hù)作用,使用加入SAP這種方式來達(dá)到自養(yǎng)護(hù)的效果是可行的。
[Abstract]:In recent years, concrete-filled steel tubular (CFST) has been used in high-rise buildings and super-high-rise buildings, but the quality of concrete-filled steel tubular (CFST) pouring and its later maintenance have been the blind spots in practical application. The appearance of self-compacting self-curing concrete provides a new way to solve the problem of concrete pouring quality and later curing. In this paper, a large number of experiments have been carried out to study the addition of superabsorbent resin SAP on the basis of self-compacting concrete to obtain the concrete which can not only satisfy the self-compacting performance but also achieve a certain self-curing effect. In this paper, the mechanical properties of self-compacting concrete with different SAP content and multiple of extra water diversion are studied by using two basic parameters: the addition of SAP and the multiple of extra water diversion. Changes of volume stability and evaluation of self-curing effect. Based on the theory of humidity diffusion, the differential equation of humidity field in SAP-SCC before and after the release of SAP water is established, which provides a theoretical basis for explaining the mechanism of SAP self-curing, and also provides a way of thinking for quantitative analysis of SAP self-curing. In this paper, the mix ratio of SCC is designed based on the standard method, and based on the Powers theory, the theoretical SAP content and the extra water diversion are obtained, and the SAP-SCC trial match is carried out. The results show that the strength of concrete can not be significantly decreased with proper SAP content and extra water diversion ratio, and the 28d strength is slightly increased. The results show that the concrete strength is satisfied with the requirements of workability and mechanical properties. The results of SAP-SCC mechanical test show that the concrete strength can not be significantly decreased with proper SAP content and extra water diversion ratio. However, neither the addition of SAP nor the multiple of extra water diversion should be too large, otherwise the strength of concrete at different ages will decrease significantly. The optimum dosage of SAP in this paper is about 0.15% of the cementing material. The results of the bulk stability test of SAP-SCC show that the free shrinkage and autogenous shrinkage of concrete can be significantly reduced after the addition of SAP-SCC to the concrete. Before the release of water, the optimum amount of additional water diversion is about 10 ~ 15 times (mass of superabsorbent resin). The variation trend and magnitude of free contraction and autogenous contraction between the test group and the blank reference group were basically the same. After SAP released water, the difference of shrinkage deformation between the test group and the blank reference group began to appear. In this paper, the free shrinkage and autogenous shrinkage of SAP-SCC are the best when the addition of SAP is about 0.15% and the extra water diversion is about 15 times. Based on the second theorem of Fick, the differential equation of humidity field of SAP-SCC before and after SAP water release is established by means of humidity diffusion theorem and humidity conservation. It is found that the differential equation before and after SAP release has the same form. The results show that the diffusion law of moisture field in SAP-SCC is similar before and after SAP release. Then, according to the theory of capillary pressure, the relationship between the relative humidity of concrete and the surface tension of capillary is established according to Laplace equation and Kelvin equation. According to the stress-strain relationship, the relationship between relative humidity and relative shrinkage in SAP-SCC is established. The experimental results show that the influence of SAP content and extra water diversion on the resistivity is related to the electrode embedding depth. That is, the effect of SAP content and extra water diversion on the curing effect is related to the depth of concrete. When the electrode embedding depth is less than 3cm, the proper SAP content and extra water diversion can significantly improve the humidity of concrete, thus reducing the resistivity of concrete. It can be considered that when the depth is less than 3cm, the self-curing effect of SAP is obvious. When the depth is greater than 3cm, although there is a certain self-curing effect, but no depth is less than 3cm, the effect is obvious. Based on this, it can be concluded that adding SAP and introducing extra moisture will have a certain curing effect on the concrete interior, and it is feasible to use the method of adding SAP to achieve the effect of self-curing.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TU528

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