岩石基矿物掺合料对水泥基胶凝材料性能影响研究

发布时间：2018-04-17 08:14

本文选题：岩石基矿物掺合料 + 孔结构　；参考：《中南大学》2014年硕士论文

【摘要】：摘要：在机制砂和碎石等集料的生产过程中产生的岩石基矿物掺合料按化学成分的不同可分为钙质和硅质两大类,开展岩石基矿物掺合料对水泥基胶凝材料性能的影响研究,对其加以利用,不仅能减少水泥用量,改善水泥基胶凝材料性能,还能降低环境污染,具有很好的技术经济效益。同时,为岩石基矿物掺合料在工程中的广泛应用奠定理论基础。本文依托国家自然科学基金项目“新型岩石基矿物掺合料体系的理论基础与工程应用研究(项目编号51278497)”,主要针对水泥-岩石基矿物掺合料胶凝体系物理力学性能和耐久性等问题进行了研究。分析了钙质岩石基矿物掺合料和硅质岩石基矿物掺合料分别对水泥凝结时间、胶砂流动性、强度性能和抗硫酸盐侵蚀性能的影响规律。主要研究内容和成果如下： 1.研究了岩石基矿物掺合料对水泥凝结时间和流动性的影响 (1)石灰石粉和大理石粉显著缩短了水泥净浆的初凝和终凝时间,且随其掺量的增加,水泥的凝结时间呈逐渐减小的趋势；水凝胶砂的流动度随石灰石粉和大理石粉的掺加而得以改善,且石粉掺量越多,水凝胶砂流动度越大。随白云石粉掺量的增加,水泥净浆的初凝和终凝时间均较基准组有所延长；白云石粉掺量较低时,水泥胶砂的流动度较基准组显著提高,但随其掺量的增加,水泥胶砂的流动度逐渐降低。 (2)花岗岩石粉和石英石粉的掺入对水泥净浆的初凝、终凝的影响规律一致,即水泥净浆的初凝、终凝时间均较基准组显著缩短；随花岗岩石粉掺量的增加,水泥凝结时间呈逐渐增大的趋势。玄武岩石粉的掺加使得水泥的初凝、终凝时间均较基准组缩短,且随玄武岩石粉掺量的增加,凝结时间逐渐减小。花岗岩、玄武岩和石英石粉对水泥胶砂流动度的影响一致,当其掺量较小时,能有效提高水泥胶砂的流动度,但随其掺量的增加,水泥胶砂流动度逐渐降低。 2.研究了岩石基矿物掺合料对水泥胶砂强度的影响 (1)石灰石粉、白云石粉和大理石粉三种钙质岩石基矿物掺合料能提高水泥胶砂早龄期强度,且试件的抗折强度随掺合料掺量的增加呈先增大后降低的趋势,当掺量为5%时,水泥胶砂强度达最大；但水泥胶砂后期强度则随掺合料掺量的增加而逐渐降低,且均低于基准组。当钙质岩石基矿物掺合料掺量一定时,随其细度的增大,水泥胶砂强度大致呈先增大后降低的趋势。 (2)花岗岩石粉、玄武岩石粉及石英石粉三种硅质岩石基矿物掺合料的掺入使得水泥胶砂各龄期强度均低于基准组,且掺量越大,强度降低越显著。花岗岩石粉和石英石粉等量取代水泥时,水泥胶砂试件抗折强度随其掺量的增加而逐渐降低,早龄期抗压强度随掺量的增加呈先增大后降低的趋势；掺玄武岩石粉的水泥胶砂试件抗折、抗压强度均随其掺量的增加呈先增大后降低的趋势,当玄武岩石粉掺量为10%时,水泥胶砂强度达最大。 3.研究了岩石基矿物掺合料对水泥胶砂孔结构的影响适量掺量的钙质岩石基矿物掺合料能降低水泥胶砂早龄期的质量吸水率和平均孔径,水泥胶砂14d至56d龄期的质量吸水率和平均孔径均高于基准组,且随钙质岩石基矿物掺合料掺量的增加而逐渐增大。硅质岩石基矿物掺合料的掺入增大了水泥胶砂各龄期的孔隙率,且掺量越多,孔隙率越大。 4.研究了岩石基矿物掺合料对混凝土抗氯离子渗透性能的影响钙质和硅质岩石基矿物掺合料的掺入均对混凝土28d龄期时的抗氯离子渗透性能产生不利影响,混凝土的电通量随掺合料掺量的增加呈逐渐增大的趋势,且均高于基准组。 5.研究了掺石灰石粉水泥净浆在低温硫酸盐侵蚀下的破坏及其作用机理掺石灰石粉的水泥净浆试件浸泡于低温(5℃)环境下不同浓度的Na2SO4溶液以及5%MgSO4溶液中时,均发生了碳硫硅钙石型硫酸盐侵蚀,且随着腐蚀时间的延长和硫酸钠浓度的增加,净浆表面的腐蚀破坏加剧。这是由于溶液中的S042-通过孔隙渗透至水泥石内部,直接与水泥石中的Ca(OH)2或C-S-H凝胶反应生成CaSO4·2H2O,在低温环境下,C-S-H凝胶与CaSO4·2H2O、石灰石粉和水直接反应生成碳硫硅钙石。当溶液浓度均为5%时,浸泡于MgSO4溶液中的净浆试件比Na2SO4溶液中的试件腐蚀更为严重。这是因为该过程不仅发生了外部的SO42-9渗透至水泥石内部生成碳硫硅钙石的反应,还生成了Mg(OH)2,导致了C-S-H凝胶的分解,进一步促进了碳硫硅钙石的生成反应。
[Abstract]:Abstract : The rock - based mineral admixture produced in the course of producing aggregate such as mechanism sand and crushed stone can be divided into two categories of calcium and siliceous rock according to the chemical composition , and the influence of rock - based mineral admixture on the properties of cement - based cementing material is studied . It can not only reduce the cement consumption , improve the properties of cement - based cementing material , but also reduce environmental pollution , and has good technical and economic benefits .

Based on the theoretical basis and engineering application of the new rock - based mineral admixture system of the National Natural Science Foundation Project ( Project No . 51278497 ) , this paper mainly studies the physical and mechanical properties and durability of cement - rock - based mineral admixture cementing system .

1 . The influence of rock - based mineral admixture on the setting time and fluidity of cement is studied .

( 1 ) the lime stone powder and the marble powder remarkably shorten the initial setting and the final setting time of the cement paste , and the setting time of the cement gradually decreases with the increase of the mixing amount thereof ;
The fluidity of the hydrogel is improved with the addition of limestone powder and marble powder , and the more the content of stone powder is , the greater the flow degree of the hydrogel sand . With the increase of the amount of dolomite powder , the initial setting and the final setting time of the cement paste are prolonged compared with the reference group ;
When the amount of dolomite powder is low , the fluidity of cement sand is obviously improved compared with the reference group , but the fluidity of cement sand is gradually decreased with the increase of mixing amount .

( 2 ) The effect of the mixing of granite stone powder and quartz stone powder on the initial setting and final setting of cement paste is consistent , that is , the initial setting and the final setting time of cement paste are obviously shortened compared with the reference group ;
With the increase of the content of the granite stone powder , the setting time of cement is gradually increased . The addition of basalt stone powder makes the initial setting and final setting time of the cement be shorter than that of the reference group , and the setting time is gradually decreased with the increase of the content of the basalt stone powder . The granite , basalt and quartz stone powder have the same effect on the fluidity of the cement mortar , but the fluidity of the cement mortar can be effectively improved when the amount of the granite , basalt and quartz stone powder is increased . However , the fluidity of the cement mortar decreases with the increase of the mixing amount .

2 . The influence of rock - based mineral admixture on the strength of cement mortar is studied .

( 1 ) The lime stone powder , dolomite powder and marble powder three calcareous rock - based mineral admixture can improve the early age strength of the cement mortar , and the flexural strength of the test piece decreases with the increase of the blending amount of the admixture , and the strength of the cement mortar reaches the maximum when the mixing amount is 5 % ;
however , that late strength of cement mortar gradually decrease with the increase of the amount of admixture , and is lower than that of the reference group .

( 2 ) The incorporation of three kinds of siliceous rock - based mineral admixtures of granite stone powder , basalt stone powder and quartz stone powder makes the strength of each age of the cement paste lower than that of the reference group , and the higher the mixing amount , the more significant the strength decreases . When the equivalent amount of the granite stone powder and quartz stone powder replaces the cement , the flexural strength of the cement colloidal sand test piece decreases gradually with the increase of the content of the mixture , and the compressive strength of the early - age compressive strength decreases with the increase of the mixing amount ;
The flexural and compressive strength of the cement - cement sand samples with basalt rock powder increase with the increase of their content , and the strength of cement mortar is the biggest when the content of basalt stone powder is 10 % .

3 . The influence of rock - based mineral admixture on the pore structure of cement mortar is studied .

The quality water absorption and average pore size of cement - cement - sand early - age are reduced by appropriate amount of calcium - rock - based mineral admixture , and the quality water absorption and average pore diameter of cement - cement sand from 14d to 56d are higher than that of the reference group , and gradually increase with the increase of the mixing amount of the calcium - rock - based mineral admixture . The incorporation of the siliceous rock - based mineral admixture increases the porosity of each age of the cement - cement sand , and the higher the mixing amount , the greater the porosity .

4 . The influence of rock - based mineral admixture on chloride ion permeability of concrete is studied .

Both the calcium and the siliceous rock - based mineral admixture have an adverse effect on the anti - chloride ion permeability during the 28d age of the concrete , and the electric flux of the concrete gradually increases with the addition of the admixture , and is higher than the reference group .

5 . The damage and mechanism of cement paste with limestone powder under low temperature sulfate attack are studied .

When the concentration of the solution is 5 % , the C - S - H gel is directly reacted with Ca ( OH ) 2 or C - S - H gel in cement stone to form CaSO4.2H2 . When the concentration of the solution is 5 % , the C - S - H gel is directly reacted with Ca ( OH ) 2 or C - S - H gel in cement stone to form CaSO4 路 2H 2O .

【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.01

【参考文献】