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摘要

加氣混凝土是應(yīng)用最為廣泛的水熱合成硅酸鹽材料，具有質(zhì)量輕、導(dǎo)熱系數(shù)低，市場(chǎng)潛力巨大，在2013年國(guó)家發(fā)改委、住房和城鄉(xiāng)建設(shè)部制定的《綠色建材行業(yè)方案》中被列為“安全耐久、節(jié)能環(huán)保、便利的綠色建材”。但是，高吸水率和高收縮的性能缺陷，常導(dǎo)致加氣混凝土墻體開(kāi)裂。本文通過(guò)材料組成和微觀結(jié)構(gòu)優(yōu)化，使加氣混凝土性能滿足自保溫墻體使用要求。主要研究?jī)?nèi)容和結(jié)果如下：

基于試驗(yàn)研究和統(tǒng)計(jì)分析，揭示了加氣混凝土吸水率對(duì)其干燥收縮性能的影響規(guī)律，建立了加氣混凝土強(qiáng)度與材料組成和結(jié)構(gòu)的關(guān)系。研究發(fā)現(xiàn)：加氣混凝土干燥收縮是體積吸水率的四次方函數(shù)；吸水率小于11.0vol. %時(shí)，加氣混凝土收縮較小，且吸水率為11.0vol. %~18.0 vol. %時(shí)，收縮值增量較??；吸水率大于26.1vol. %時(shí)，加氣混凝土的干燥收縮值顯著增加；加氣混凝土最優(yōu)鈣硅比為0.74，降低毛細(xì)孔體積率是實(shí)現(xiàn)加氣混凝土減縮增強(qiáng)的有效途徑。

研究了膠結(jié)料、鋁摻雜和專用減水劑對(duì)加氣混凝土強(qiáng)度和收縮性能的影響，通過(guò)XRD和SEM等方法，分析了水熱合成產(chǎn)物。研究發(fā)現(xiàn)：低溫熟料和鋁摻雜基料改變了水熱合成產(chǎn)物構(gòu)成，前者促進(jìn)了高強(qiáng)度水化鈣黃長(zhǎng)石形成，后者促進(jìn)了C-A-S-H的形成，從而獲得低收縮、高強(qiáng)度加氣混凝土；專用減水劑通過(guò)降低水料比和毛細(xì)孔體積率，使加氣混凝土收縮降低、強(qiáng)度提高。

基于BSE圖像分析，定量了高性能砂加氣混凝土和粉煤灰加氣混凝土的晶體的體積率和膠體的體積率。研究發(fā)現(xiàn)：在相同的水熱合成工藝條件下，高性能砂加氣混凝土的晶體與膠體總體積率為粉煤灰加氣混凝土的1.4倍，兩種加氣混凝土的晶體/膠體體積比分別為1.7和1.2。

工業(yè)化應(yīng)用試驗(yàn)表明，通過(guò)優(yōu)化加氣混凝土配比，降低毛細(xì)孔體積率，可顯著提升加氣混凝土強(qiáng)度和體積穩(wěn)定性。

關(guān)鍵詞：建筑材料；加氣混凝土；微觀結(jié)構(gòu)；強(qiáng)度；晶膠比

 

                                                                   

Abstract

    Aerated concrete is the most used hydrothermal silicate material, has the advantages of light weight, low thermal conductivity, market potential is tremendous, in 2013 the national development and Reform Commission, the Ministry of housing 、 urban and rural construction to develop "green building materials industry plan" is listed as "safety and durability, energy saving and environmental protection, convenience of green building materials". However, the high water absorption rate and the performance of the high shrinkage defects, often lead to aerated concrete wall cracking. In this paper, the performance of aerated concrete can meet the requirements of self-insulation wall using the material composition and microstructure optimization. The main research contents and results are as follows:

    Based on the experimental study and statistical analysis, the influence of the water absorption rate of aerated concrete on drying shrinkage of the aerated concrete is revealed, and the relationship between the strength of aerated concrete and the structure of the air entrained concrete is established.It is found that the drying shrinkage of autoclaved aerated concrete is volume water absorption rate of the quartic function; the bibulous rate is less than of 11.0vol%, aerated concrete shrinkage is small, and when the water absorbing rate for 11.0vol.%~18.0 vol.% , shrinkage value incremental is smaller; water absorption rate  greater than 26.1vol.% , drying shrinkage of autoclaved aerated concrete value increased significantly; aerated concrete optimal calcium silicon ratio 0.74, reduce the volume ratio of pores is the effective way to realize the reduction of aerated concrete reinforced.

    The influence of cement, Al doping and special water reducer on the strength and shrinkage of aerated concrete was studied. The hydrothermal silicate material were analyzed by SEM and XRD.It was found that the low temperature clinker and aluminum doped base material change constitutes of hydrothermal silicate material , the former promotes the formation of high strength water gehlenite,the later promote the C-A-S-H formation, resulting in low shrinkage, high strength aerated concrete; special water reducing agent by reducing water material ratio and pore volume rate, aerated concrete shrinkage is reduced, and the strength increase.

    Based on the BSE image analysis, the volume rate of the crystal and the volume rate of the colloidal volume of high performance sand aerated concrete and fly ash aerated concrete are quantitatively analyzed. Study found that: under the same hydrothermal synthesis process conditions, high performance aerated concrete colloidal crystals with the total volume rate is 1.4 times that of the fly ash aerated concrete, two aerated concrete of crystal / colloid volume ratio, 1.7 and 1.2, respectively.

    Industrial application test showed that by optimizing the ratio of aerated concrete, reduce the volume ratio of pores, can significantly improve the strength and volume stability of aerated concrete.

Key words:Building materials; aerated concrete; microstructure; strength;shrinkage；