脫硫石膏—粉煤灰膠凝體系性能研究
發(fā)布時(shí)間：2018-09-01 06:18
【摘要】：脫硫石膏和粉煤灰是能夠被廣泛利用的工業(yè)廢渣，脫硫石膏經(jīng)煅燒可以制備建筑石膏，建筑石膏與粉煤灰復(fù)合可以制備一種新的膠凝體系，該膠凝體系既具有建筑石膏輕質(zhì)、快硬、體積穩(wěn)定的特點(diǎn)，又由于粉煤灰受硫酸鹽激發(fā)后生成水硬性水化產(chǎn)物，而具有耐水、后期強(qiáng)度高的特點(diǎn)，但目前該復(fù)合膠凝材料體系尚無(wú)系統(tǒng)研究。本文對(duì)脫硫石膏-粉煤灰膠凝體系的漿體流動(dòng)性、凝結(jié)時(shí)間、強(qiáng)度及耐久性進(jìn)行了系統(tǒng)研究，并對(duì)不同外加劑（激發(fā)劑、減水劑、緩凝劑）以及玻璃纖維對(duì)脫硫石膏-粉煤灰復(fù)合膠凝體系性能的影響規(guī)律進(jìn)行了探討。在此基礎(chǔ)上，研究了脫硫石膏-粉煤灰-水泥三元膠凝體系的特點(diǎn)，并通過(guò)XRD、SEM及水化熱等測(cè)試，探討了二元體系及三元體系的水化機(jī)理。主要研究?jī)?nèi)容及結(jié)果如下： 首先，本文研究了脫硫石膏-粉煤灰膠凝體系的性能特點(diǎn)及水化機(jī)理： 粉煤灰加入到脫硫石膏體系中，會(huì)提高膠凝體系的流動(dòng)性能，延長(zhǎng)凝結(jié)時(shí)間。減少膠凝體系的放熱量。由于前期粉煤灰較少參與水化反應(yīng)，粉煤灰的加入會(huì)降低膠凝體系的早期強(qiáng)度；不同類型的激發(fā)劑（石灰、堿、硫酸鹽、硅酸鹽、氯鹽）對(duì)二元體系的強(qiáng)度有一定的激發(fā)作用。對(duì)二元體系最有效的復(fù)合激發(fā)劑為石灰、氯化鈣和硫酸鋁鉀復(fù)摻；減水劑的摻入能提高膠凝體系的強(qiáng)度，增加流動(dòng)性能。且萘系減水劑對(duì)二元體系強(qiáng)度提高效果好于聚羧酸減水劑，但聚羧酸減水劑對(duì)體系的流動(dòng)性能增強(qiáng)效果更好；檸檬酸和三聚磷酸鈉能夠延緩該膠凝體系的凝結(jié)時(shí)間，檸檬酸對(duì)二元膠凝體系的凝結(jié)時(shí)間延緩效果更好，且凝結(jié)時(shí)間延緩的越多，對(duì)于強(qiáng)度的損失就越大。 玻璃纖維的加入能夠提高二元膠凝體系的抗折強(qiáng)度，但摻量過(guò)多后，會(huì)損害抗折強(qiáng)度。10mm玻璃纖維較20mm的玻璃纖維更適合此體系，且摻量為1%的10mm玻璃纖維能使膠凝體系的強(qiáng)度性能達(dá)到最優(yōu)。 其次，本文研究了脫硫石膏-粉煤灰-水泥膠凝體系的性能特點(diǎn)及水化機(jī)理： 水泥加入到脫硫石膏-粉煤灰體系中，會(huì)提高膠凝體系的流動(dòng)性能，縮短凝結(jié)時(shí)間，并提高膠凝體系的強(qiáng)度；不同類型的激發(fā)劑（石灰、堿、硫酸鹽、硅酸鹽、氯鹽）對(duì)三元體系的強(qiáng)度有一定的激發(fā)作用。對(duì)三元膠凝體系激發(fā)效果最好的復(fù)合激發(fā)劑為石灰、氯化鈣、硫酸鈉復(fù)摻；減水劑的摻入能提高膠凝體系的強(qiáng)度，增加流動(dòng)性能。且萘系減水劑對(duì)三元體系強(qiáng)度的提高效果好于聚羧酸高效減水劑，但聚羧酸高效減水劑對(duì)流動(dòng)性增強(qiáng)效果更好；檸檬酸和三聚磷酸鈉對(duì)膠凝體系的凝結(jié)時(shí)間有延緩作用。檸檬酸對(duì)三元膠凝體系的緩凝效果更好。 與純石膏膠凝體系相比，脫硫石膏-粉煤灰-水泥膠凝體系具有較好的耐水性，經(jīng)過(guò)25次凍融循環(huán)后，三元膠凝體系試件的質(zhì)量隨著脫硫石膏摻量的增加而增大；在CO2濃度為75%的氣體中，由于體系中OH-的匱乏，，此復(fù)合膠凝體系的碳化速度較快；由于石膏的微膨脹性，可抵消一部分水泥體系自身不可避免的收縮，因此，與純水泥膠凝體系相比，三元膠凝體系體積變化率較小，體積穩(wěn)定性較好。 以上研究結(jié)果表明，脫硫石膏-粉煤灰二元膠凝體系和脫硫石膏-粉煤灰-水泥三元膠凝體系能在大量利用工業(yè)固體廢棄物的同時(shí)，形成性能獨(dú)特的復(fù)合膠凝體系，具有良好的應(yīng)用價(jià)值。
[Abstract]:Desulfurization gypsum and fly ash are industrial waste residues that can be widely used. Desulfurization gypsum can be calcined to prepare building gypsum. A new cementing system can be prepared by compounding building gypsum and fly ash. The cementing system not only has the characteristics of light weight, fast hardening and stable volume of building gypsum, but also produces water after being stimulated by sulfate. In this paper, the fluidity, setting time, strength and durability of desulfurized gypsum-fly ash cementitious system are systematically studied, and different admixtures (activator, water reducer, retarder) and glass fiber are also studied. On the basis of this, the characteristics of desulfurized gypsum-fly ash-cement ternary cementitious system were studied. The hydration mechanism of binary system and ternary system was discussed by XRD, SEM and hydration heat test.
First of all, the performance characteristics and hydration mechanism of desulphurization gypsum fly ash cementitious system are studied.
Adding fly ash to the desulfurization gypsum system will improve the flowability of the cementitious system, prolong the setting time and reduce the heat release of the cementitious system. Lime, calcium chloride and potassium aluminium sulfate are the most effective compound activator for binary system, and the addition of water reducer can improve the strength and fluidity of binary system, and naphthalene water reducer can improve the strength of binary system better than Polycarboxylic Water reducer, but polycarboxylic water reducer can improve the body. Citric acid and sodium tripolyphosphate can delay the setting time of the binary cementitious system. Citric acid has a better effect on the setting time of binary cementitious system, and the more the setting time is delayed, the greater the loss of strength.
The addition of glass fiber can improve the flexural strength of binary cementitious system, but excessive dosage will damage the flexural strength. 10mm glass fiber is more suitable for this system than 20mm glass fiber, and the 10 mm glass fiber with 1% dosage can make the strength performance of the cementitious system reach the optimum.
Secondly, the performance characteristics and hydration mechanism of desulphurization gypsum fly ash cement cementing system are studied.
When cement is added to the desulfurized gypsum-fly ash system, the fluidity of the cementitious system will be improved, the setting time will be shortened, and the strength of the cementitious system will be enhanced. Different types of activators (lime, alkali, sulfate, silicate, chloride) have certain excitation effect on the strength of the ternary system. Lime, calcium chloride and sodium sulfate are used as hair additives, and the addition of water reducer can improve the strength and fluidity of the cementitious system. The setting time has a delayed effect. Citric acid has better retarding effect on the cementing system of three yuan.
Compared with the pure gypsum cementitious system, the desulfurized gypsum-fly ash-cement cementitious system has better water resistance. After 25 freeze-thaw cycles, the quality of the ternary cementitious system specimen increases with the increase of the dosage of desulfurized gypsum; in the gas with 75% CO2 concentration, the carbonization rate of the composite cementitious system is due to the lack of OH-in the system. Because of the expansion of gypsum, it can counteract the inevitable shrinkage of some cement systems, so the volume change rate of ternary cementitious system is smaller and the volume stability is better than that of pure cement cementitious system.
The results show that the desulfurized gypsum-fly ash binary cementitious system and the desulfurized gypsum-fly ash-cement ternary cementitious system can form a composite cementitious system with unique properties and have good application value.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU528
本文編號(hào)：2216366
[Abstract]:Desulfurization gypsum and fly ash are industrial waste residues that can be widely used. Desulfurization gypsum can be calcined to prepare building gypsum. A new cementing system can be prepared by compounding building gypsum and fly ash. The cementing system not only has the characteristics of light weight, fast hardening and stable volume of building gypsum, but also produces water after being stimulated by sulfate. In this paper, the fluidity, setting time, strength and durability of desulfurized gypsum-fly ash cementitious system are systematically studied, and different admixtures (activator, water reducer, retarder) and glass fiber are also studied. On the basis of this, the characteristics of desulfurized gypsum-fly ash-cement ternary cementitious system were studied. The hydration mechanism of binary system and ternary system was discussed by XRD, SEM and hydration heat test.
First of all, the performance characteristics and hydration mechanism of desulphurization gypsum fly ash cementitious system are studied.
Adding fly ash to the desulfurization gypsum system will improve the flowability of the cementitious system, prolong the setting time and reduce the heat release of the cementitious system. Lime, calcium chloride and potassium aluminium sulfate are the most effective compound activator for binary system, and the addition of water reducer can improve the strength and fluidity of binary system, and naphthalene water reducer can improve the strength of binary system better than Polycarboxylic Water reducer, but polycarboxylic water reducer can improve the body. Citric acid and sodium tripolyphosphate can delay the setting time of the binary cementitious system. Citric acid has a better effect on the setting time of binary cementitious system, and the more the setting time is delayed, the greater the loss of strength.
The addition of glass fiber can improve the flexural strength of binary cementitious system, but excessive dosage will damage the flexural strength. 10mm glass fiber is more suitable for this system than 20mm glass fiber, and the 10 mm glass fiber with 1% dosage can make the strength performance of the cementitious system reach the optimum.
Secondly, the performance characteristics and hydration mechanism of desulphurization gypsum fly ash cement cementing system are studied.
When cement is added to the desulfurized gypsum-fly ash system, the fluidity of the cementitious system will be improved, the setting time will be shortened, and the strength of the cementitious system will be enhanced. Different types of activators (lime, alkali, sulfate, silicate, chloride) have certain excitation effect on the strength of the ternary system. Lime, calcium chloride and sodium sulfate are used as hair additives, and the addition of water reducer can improve the strength and fluidity of the cementitious system. The setting time has a delayed effect. Citric acid has better retarding effect on the cementing system of three yuan.
Compared with the pure gypsum cementitious system, the desulfurized gypsum-fly ash-cement cementitious system has better water resistance. After 25 freeze-thaw cycles, the quality of the ternary cementitious system specimen increases with the increase of the dosage of desulfurized gypsum; in the gas with 75% CO2 concentration, the carbonization rate of the composite cementitious system is due to the lack of OH-in the system. Because of the expansion of gypsum, it can counteract the inevitable shrinkage of some cement systems, so the volume change rate of ternary cementitious system is smaller and the volume stability is better than that of pure cement cementitious system.
The results show that the desulfurized gypsum-fly ash binary cementitious system and the desulfurized gypsum-fly ash-cement ternary cementitious system can form a composite cementitious system with unique properties and have good application value.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU528
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