本文選題：混凝土　切入點：無機鹽　出處：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：無機鹽外加劑由于它的經(jīng)濟適用性經(jīng)常被用于混凝土工程中,起到早強、防凍、速凝等作用。當(dāng)無機鹽加入后可參與到水泥水化反應(yīng)中,會對水泥石早期及后期內(nèi)部結(jié)構(gòu)產(chǎn)生一定的影響。本文主要對單摻無機鹽(NaCl、Ca(NO_2)_2、Ca(NO_3)_2、Na_2SO_4、NaNO_2)、粉煤灰與無機鹽混摻下混凝土的界面過渡區(qū)性能、孔結(jié)構(gòu)及氣孔結(jié)構(gòu)進行測試與觀察。利用顯微硬度儀觀察摻加無機鹽后的混凝土界面過渡區(qū)的顯微硬度及厚度情況,比較發(fā)現(xiàn)Na Cl、Ca(NO_3)_2的加入會使顯微硬度有所增加;Ca(NO_2)_2和NaNO_2會使顯微硬度降低;低摻量Na_2SO_4對顯微硬度影響不大,高摻量會使顯微硬度明顯下降。NaCl、Ca(NO_2)_2、NaNO_2的摻入對界面厚度影響不大,Ca(NO_3)_2、Na_2SO_4會使界面區(qū)厚度有所增大。摻入粉煤灰后會使界面區(qū)的顯微硬度值有所降低;除了Na_2SO_4與粉煤灰混摻后會使界面厚度減小,其它無機鹽與粉煤灰混摻均會使界面厚度增加。利用氮吸附儀及壓汞儀測試無機鹽摻加后孔結(jié)構(gòu)的變化情況,發(fā)現(xiàn)NaCl、Na_2SO_4的加入會對早期孔結(jié)構(gòu)有細化作用,Ca(NO_2)_2及Ca(NO_3)_2會對早期孔結(jié)構(gòu)有粗化效果;無機鹽的摻入均會使后期的孔結(jié)構(gòu)發(fā)展變緩。摻入粉煤灰后無機鹽對早期孔結(jié)構(gòu)無明顯作用,28d齡期后,NaCl的加入有效的減少了最可幾孔的數(shù)量,NaNO_2及Ca(NO_2)_2的加入也有上述的作用。其它無機鹽加入后會使最可幾孔數(shù)量及孔徑減小,而且Ca(NO_3)_2的加入還使最可幾孔孔徑增大。采用顯微鏡觀察硬化非引氣混凝土的氣孔結(jié)構(gòu),發(fā)現(xiàn)除Na_2SO_4能增大含氣量外,其它無機鹽的加入均對混凝土的含氣量有或多或少的降低作用;NaCl對氣孔平均半徑影響不大,Ca(NO_2)_2、Ca(NO_3)_2及Na_2SO_4的摻入會使氣孔平均半徑增大;NaNO_2的摻入會使氣孔半徑有所降低;NaCl、Ca(NO_2)_2、Ca(NO_3)_2、Na_2SO_4的摻入會不同程度的增大氣泡間距系數(shù),NaNO_2的加入會降低氣泡間距系數(shù)。當(dāng)粉煤灰摻入時,Ca(NO_2)_2、Ca(NO_3)_2、Na_2SO_4及NaNO_2四種無機鹽隨著粉煤灰摻量的增加各個含氣量都有所增加,NaCl的含氣量呈現(xiàn)先降低后增大的變化;隨著粉煤灰摻量的增加氣孔平均半徑與氣泡間距系數(shù)都在不斷的減小。
[Abstract]:Inorganic salt admixtures are often used in concrete engineering because of their economic applicability, which play a role of early strength, anti-freezing, quick setting, etc. When inorganic salts are added, they can participate in the hydration reaction of cement. This paper mainly deals with the interfacial transition zone performance of concrete mixed with inorganic salt, NaClCl-CaNO2 + + 2CaNO3 / 2CaNO3 / 2 / Na2SO4 / NaNO2, and the interfacial transition zone of concrete mixed with fly-ash and inorganic salt, which has a certain effect on the internal structure of cement stone in its early and late stages. The main purpose of this paper is to study the properties of the interfacial transition zone of concrete mixed with inorganic salt and fly ash. The pore structure and pore structure were tested and observed. The microhardness and thickness of the transition zone of concrete interface after adding inorganic salt were observed by microhardness tester. It was found that the addition of NaCl-CaNo3 / s _ 2 would increase the microhardness, and that the microhardness would be decreased with the addition of Na_2SO_4 and NaNO_2, while the microhardness would not be affected by the addition of low content of Na_2SO_4. The microhardness of the interface decreases obviously with the addition of high dosage. The addition of NaCl-CaNO-2S _ 2S _ 2 has little effect on the interface thickness. The thickness of the interface area is increased by the addition of fly ash, and the microhardness value of the interface region is decreased after the addition of fly ash. In addition to Na_2SO_4 and fly ash mixing, the interfacial thickness will decrease, but other inorganic salts and fly ash will increase the interfacial thickness. The pore structure changes after adding inorganic salt are measured by nitrogen adsorption instrument and mercury injection meter. It is found that the addition of NaCl-Na _ 2SO _ 4 can refine the early pore structure and that Ca(NO_3)_2 can coarsening the early pore structure. The addition of inorganic salt can slow down the development of pore structure in the later stage. The addition of inorganic salt has no obvious effect on the early pore structure after the addition of fly ash, and the addition of nano _ 2 and Ca(NO_2)_2 can effectively reduce the number of the most available pores after 28 days of age. The addition of other inorganic salts will reduce the number and pore size of the most probable pores, The pore structure of hardened non-air-entraining concrete was observed by microscope, and it was found that the pore structure of hardened non-air-entraining concrete could be increased with the addition of Ca(NO_3)_2, except that Na_2SO_4 could increase the gas content. The addition of other inorganic salts has a more or less effect on the air content of concrete. The effect of NaCl on the mean pore radius is not significant. The addition of Na_2SO_4 and the incorporation of Na_2SO_4 can increase the mean radius of the pore. The addition of NANO2 will reduce the radius of the pore. The addition of NaNO2 will decrease the bubble spacing coefficient. When the fly ash is added, the gas content of each of the four inorganic salts, Na2SO4 and NaNO_2, will increase with the increase of fly ash content, and the gas content of NaCl will increase with the increase of fly ash content, and the gas content of each inorganic salt will be increased with the increase of fly ash content, and the gas content of NaCl will be increased by the addition of NaNO2. When the fly ash is mixed in, the gas content of each inorganic salt will increase with the addition of fly ash. The quantity decreased first and then increased. With the increase of fly ash content, the mean radius of pores and the coefficient of bubble spacing are decreasing.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU528.042

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