湿拌砂浆的性能研究

发布时间：2018-08-30 20:37

【摘要】：随着中国新型城镇化的发展加速，城市市政基础建设、住宅的数量必将大幅增多，而建筑能耗在整体能耗中已占据相当大的部分。建筑砂浆作为仅次于墙体材料和混凝土的大宗建筑材料，每年的用量达数亿吨之多，就当前国内形势来看，湿拌砂浆这一绿色建材的推广势在必行。而与发达国家相比，我国对湿拌砂浆的研究起步较晚，普及推广也较慢，因此对研究如何配制和易好、工作性能保持能力强、耐久性好的湿拌砂浆就显得很有必要。本文主要研究了胶砂比对湿拌砂浆性能的影响，在选定胶砂比后，还研究了外加剂、不同组分及不同时刻的二次加水对湿拌砂浆性能的影响。主要的研究内容有以下几点：首先，研究了胶砂比对素水泥砂浆性能的影响及不同组分下湿拌砂浆的性能变化规律。研究结果表明，随着胶砂比的减小，砂浆的分层度、稠度经时损失及砂浆的干缩均逐渐增大；28d抗压和抗折强度逐渐减小；凝结时间逐渐增长。当胶砂比为1:3时，在砂浆中用双飞粉取代砂、粉煤灰取代水泥及石灰膏取代水泥均可以改善砂浆的工作性能，其中双飞粉取代量不宜超过砂质量的30%，粉煤灰和石灰膏不宜超过水泥质量的20%；其次，研究了外加剂种类及掺量对不同组分湿拌砂浆性能的影响。研究结果表明，在不同组分的湿拌砂浆中掺入减水剂、保水剂和缓凝剂，均可以不同程度地改善砂浆的保水性、干燥收缩、稠度经时损失及凝结时间。外加剂掺量并非越大越好，而是存在着一个相对最佳的范围，且各外加剂在不同组分的湿拌砂浆中的饱和掺量有所不同。再次，通过在不同时刻对不同组分的湿拌砂浆进行二次加水拌合，来考察其对不同组分下湿拌砂浆的性能影响。在力学性能方面，二次加水拌合对砂浆28d抗压强度有不同程度的降低，其降低幅度为：水泥-石灰膏-砂水泥-砂水泥-粉煤灰-砂水泥-双飞粉-砂；在耐久性方面，二次加水拌合对耐久性也有不同程度的削弱，其削弱幅度为：水泥-石灰膏-砂水泥-粉煤灰-砂水泥-砂水泥-双飞粉-砂。因此，对于“水泥-石灰膏-砂”和“水泥-粉煤灰-砂”湿拌砂浆来说，应尽量避免二次加水拌合，若有不得不进行二次加水拌合的情况，则可选用“水泥-双飞粉-砂”湿拌砂浆来适当抵消因二次拌合后各项性能的削弱。最后，综合所做试验得出的凝结时间-贯入阻力曲线图分析得出，贯入阻力值与可操作时间存在着一定的对应关系，当贯入阻力介于0-0.5N之间时，砂浆仍有施工性能；当贯入阻力介于0.5-1N之间时，施工性能逐渐变差；当贯入阻力超过1N后，砂浆基本无施工性能。掺入各外加剂能不同程度地延长砂浆贯入阻力值达到1N左右的时间，从而延长砂浆的可操作时间。一般来说，，砂浆贯入阻力的增长趋势为两个平缓区、两个增幅区，即砂浆贯入阻力在0-1N、7-10N区间增长较为平缓；贯入阻力在1-7N、10N之后的区间增长幅度明显，且其在10N之后区间的增幅要大于其在1-7N区间的增幅。
[Abstract]:With the acceleration of the development of new urbanization in China, the number of urban municipal infrastructures and residential buildings will increase dramatically, and building energy consumption has occupied a considerable part of the overall energy consumption. It is imperative to popularize Wet-mix mortar as a green building material. Compared with developed countries, the research on Wet-mix mortar in China started late and popularized slowly. Therefore, it is necessary to study how to prepare and improve the Wet-mix mortar.
This paper mainly studies the influence of mortar ratio on the properties of wet-mixed mortar. After selecting the mortar ratio, the effects of admixtures, different components and secondary water addition at different times on the properties of wet-mixed mortar are also studied.
Firstly, the influence of mortar-mortar ratio on the performance of plain cement mortar and the change rule of wet-mixed mortar under different components were studied. When the sand ratio is 1:3, the working performance of mortar can be improved by replacing sand with double fly ash, cement and lime gypsum with fly ash. The replacement quantity of double fly ash should not exceed 30% of the sand quality, and fly ash and lime gypsum should not exceed 20% of the cement quality.
Secondly, the effects of different kinds and dosages of admixtures on the properties of wet-mixed mortars with different components were studied. The results show that the water-retaining agent, water-retaining agent and retarder can improve the water-retaining property, drying shrinkage, time loss of consistency and setting time of mortars to varying degrees. Good, but there is a relatively optimum range of additives in different components of wet-mixed mortar in the saturated content is different.
Thirdly, the performance of wet-mixed mortar with different components was investigated by adding water twice at different times.
In terms of mechanical properties, the 28-day compressive strength of mortar decreased with the secondary water addition, and the decreasing extent was as follows: cement - lime gypsum - sand cement - sand cement - fly ash - sand cement - double fly ash - sand.
In the aspect of durability, the second water mixing also weakens the durability in varying degrees, the extent of which is: cement - lime gypsum - sand cement - fly ash - sand cement - sand cement - double fly ash - sand. If the secondary mixing is not carried out, the "cement-double fly ash-sand" wet mixing mortar can be selected to offset the weakening of various properties due to the secondary mixing.
Finally, the coagulation time-penetration resistance curves obtained from the tests show that there is a corresponding relationship between the penetration resistance and the operating time. When the penetration resistance is between 0-0.5N, the mortar still has the construction performance; when the penetration resistance is between 0.5-1N, the construction performance gradually becomes worse; when the penetration resistance exceeds 1N, the construction performance becomes worse. Generally speaking, the increasing trend of the penetration resistance of mortar is two gentle zones, and the two increasing zones, i.e. the penetration resistance of mortar in the range of 0-1N and 7-10N, increase slowly. The input resistance increases obviously in the interval after 1-7N and 10N, and the interval after 10N is larger than that in the interval between 1-7N.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU578.1

【参考文献】