Effect of silica fume and expanded perlite addition on the technical properties of the fly ash–lime–gypsum mixture

The main objective of this research was to investigate the effect of different type of pozzolan additions to cement free lightweight block made from fly ash–lime–gypsum mixture and observe the changes in physical, mechanical, thermal properties and microstructure. Thermal conductivity of the fly ash–lime–gypsum mixture was improved by the addition of the expanded perlite. Optimal strength-thermal conductivity combination was obtained by the usage of silica fume and expanded perlite together. Improved strength properties were obtained by using hydrothermal curing conditions and superplasticizer addition.     

癸酸-棕榈酸/膨胀珍珠岩相变石膏热学性能研究

相变储能技术对于提升建筑节能性有显著作用。本文以癸酸-棕榈酸作为相变复合材料,以膨胀珍珠岩作为吸附材料,并以建筑石膏作为胶凝材料,制备了癸酸-棕榈酸/膨胀珍珠岩相变石膏。分别对癸酸-棕榈酸相变复合材料的相变温度和相变焓值、癸酸-棕榈酸/膨胀珍珠岩相变颗粒的热稳定性、癸酸-棕榈酸/膨胀珍珠岩相变石膏的热学性能等进行了测试,分析癸酸-棕榈酸/膨胀珍珠岩相变石膏在建筑墙体中应用的可行性。     

添加剂在脱硫石膏中的应用

脱硫石膏是湿式石灰石一石膏法烟气脱硫工艺产生的工业副产品,对其进行合理利用是各级政府大力倡导的项目。脱硫石膏可以大规模用于制作石膏砌块,纸面石膏板、粉刷石膏等。脱硫石膏同天然石膏一样具有凝结时间短,耐水性差特点,研究脱硫石膏的缓凝技术和防水技术情景广阔。     

粉刷石膏在室内抹灰中的应用及施工

详细介绍了粉刷石膏本身的性能指标,混合材料的质量要求及所需的施工工具,阐述了粉刷石膏抹灰的施工工艺及注意事项,并通过工程实例对粉刷石膏的技术经济效益及社会效益进行分析。指出粉刷石膏的功能特点,很好的解决了传统的水泥砂浆或混合砂浆室内抹灰存在的空鼓、开裂、脱落等质量通病。     

Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume

The influence of nano-SiO₂ (NS) addition on properties of hardened cement paste (hcp) as compared with silica fume (SF) has been studied through measurement of compressive and bond strengths of hcp, and by XRD and SEM analysis. Results indicated that the influence of NS and SF on consistency and setting time of fresh cement paste showed different. NS made cement paste thicker and NS accelerated the cement hydration process. Compressive strengths of hcp and bond strengths of paste–aggregate interface incorporating NS were obviously higher than those incorporating SF, especially at early ages. And with increasing the NS content, the rate of bond strength increase was more than that of their compressive strength increase. With 3% NS added, NS digested calcium hydroxide (CH) crystals, decreased the orientation of CH crystals, reduced the crystal size of CH gathered at the interface and improved the interface more effectively than SF. The results suggest that with a small amount of added NS, the CH crystals at the interface between hcp and aggregate at early ages may be effectively absorbed in high performance concrete (HPC).     

粉刷石膏在室内抹灰中的应用

因传统的水泥砂浆或混合砂浆抹灰已不能满足用户对其质量的要求，而粉刷石膏以其结构稳定、不开裂、不脱皮等优点则可能成为二者的理想替代品。详细介绍了粉刷石膏的性能特点、主要性能指标，着重阐述了其施工工艺，提出了在施工中应注意的事项。并指出它的广泛使用将取得显著的经济效益和社会效益。     

水泥、粉煤灰单掺对建筑石膏性能影响

研究了水泥、粉煤灰矿物掺合料单掺对建筑石膏的强度、凝结时间、软化系数等性能的影响,结果表明,粉煤灰具有一定的缓凝作用,而水泥具有促凝作用,粉煤灰、水泥有利于提高建筑石膏的抗压软化系数,但当粉煤灰加入量超过20%(质量百分比),水泥的加入量超过9%时建筑石膏的绝干强度损失较大。     

可再分散乳胶粉对石膏性能影响的试验研究

主要阐述了掺入SP3000型可再分散性乳胶粉后,石膏硬化体力学性能及微观结构的变化规律。研究表明,随着胶粉掺量的提高,石膏砂浆抗压强度总体下降,而抗折强度逐渐增加,折压比明显增加;当胶粉掺量高于0.5%后,石膏将与聚苯板发生有效粘结,且破坏形态均为典型锥形苯板破坏;微观分析证明,可再分散性乳胶粉能在石膏晶体之间成膜,并随掺量的提高至2.5%以后,膜的分布及厚度不断增加,可有效改善石膏性能。     

Environment hazard mitigation of waste gypsum and chalk: Use in construction materials

The rapid urbanization and industrialization have resulted in the production of various types of solid, liquid and gaseous wastes which pose serious problems to the environment. The disposal and use of solid industrial wastes like phosphogypsum, fluorogypsum, fly ash, slag, and lime sludge, is significant in view of their availability and potential applications. The paper deals with studies on select wastes like phosphogypsum and chalk for use in value-added building materials. The engineering properties and techno-economics of materials like gypsum plasters, cementitious binders, boards/blocks, masonry cement and flooring tiles produced from phosphogypsum and lime have been detailed. The production and use of building materials from such wastes will protect the environment from degradation.     

Differences in the geotechnical properties of two types of gypsum: alabastrine and porphyritic

This study reports an investigation into the physical and mechanical characteristics of fine-grained (alabastrine) and coarse-grained (porphyritic) gypsum from Sivas, Turkey. The geotechnical properties improved as the grain size decreased. The Student’s t test indicated that the differences reported between the mean values of the slake durability, Schmidt hardness, unconfined compressive strength, Young’s modulus, and tensile strength of the two types of gypsum were statistically significant. The results indicate that texture, especially grain size and shape, is an important parameter controlling the differences in the mechanical properties of the two gypsum types studied.      

植物纤维增强石膏复合板力学性能研究

参照纤维复合材料的测试方法得出几种植物纤维增强石膏复合板的基本力学性能测试数据。并对不同植物纤维种类及不同的纤维掺量对复合板性能的影响进行讨论。     

外加剂对钛石膏物理性能影响的研究

通过向预处理的钛石膏中加入萘系减水剂和硫酸钠等外加剂,研究了各外加剂对钛石膏物理性能的影响,确定了各外加剂的最佳掺量,并探讨了各外加剂的作用机理。研究表明,当萘系减水剂掺量为3%时,减水效果最好,此时钛石膏试样的标稠用水量最小为126%,相比于空白试样降低了18%,2 h抗折、抗压强度分别为1.09 MPa、1.98 MPa,绝干抗折、抗压强度分别为2.24 MPa、2.77 MPa;硫酸钠掺量为1.5%时钛石膏物理性能最好,此时钛石膏凝结时间较短初凝时间和终凝时间分别为8 min和10 min,2 h抗折、抗压强度分别为1.21 MPa和2.32 MPa,绝干抗折、抗压强度分别为2.43 MPa和3.02 MPa。     

双掺硅灰、粉煤灰对青藏铁路用高性能混凝土性能的影响

本文采用在混凝土中双掺硅灰和粉煤灰及添加引气剂的方法，向青藏铁路建设用混凝土浇筑施工提供配合比，确保混凝土性能满足施工与使用要求。试验研究表明，对于水胶比为0．41左右的混凝土，该方法能明显改善混凝土的抗硫酸盐腐蚀能力，有效提高混凝土抗冻融循环达300次。根据抗氯离子渗透试验结果推测，这主要是由于混凝土中矿物掺合料与氢氧化钙发生进一步水化，增强了混凝土的密实性，改善了混凝土耐久性。     

减水剂对建筑石膏性能及水化进程的影响

考察减水剂对建筑石膏浆体流动性和石膏硬化体强度的影响，优选出适合石膏体系的减水剂，提出了抑制石膏浆体流动度经时损失的措施。通过对掺有减水剂的石膏浆体水化进程的研究发现，减水剂可加快石膏浆体的早期水化，但不影响石膏的最终水化率。     

有机硅BS94对以脱硫石膏为原料生产的耐水纸面石膏板性能的影响

探讨了不同掺量的有机硅BS94对脱硫石膏吸水率、抗折强度、抗压强度、初凝时间、终凝时间的影响规律,分析了脱硫石膏中杂质对有机硅BS94防水性能的影响。结果表明,有机硅BS94对以脱硫石膏为原料生产的耐水纸面石膏板具有较好的防水性能,可以广泛应用于以脱硫石膏生产耐水纸面石膏板的工艺中,但当脱硫石膏中的F离子含量较高时,防水剂的防水性能会有所下降,因此,应严格控制原料中可溶性F的含量。     

硅微粉对混凝土性能的影响

为开发一种新型矿物掺合料,以硅微粉为研究对象,系统研究了硅微粉混凝土的力学性能、耐久性能(抗氯离子渗透性、抗冻性)及其热物理性能.研究结果表明:硅微粉与粉煤灰复掺40%时,其中硅微粉掺量在20%以内,混凝土28 d强度可以达到40 MPa以上,硅微粉的掺入可提高混凝土的抗氯离子渗透性与抗冻性能,显著降低了混凝土的早期放热峰值与水化放热速率,从而有效地降低混凝土温度开裂敏感性,因此,硅微粉是一种具有良好应用前景的新型矿物掺合料.     

Design and construction of expanded polystyrene embankments Practical design methods as used in the United Kingdom

This paper covers the history of the use of expanded polystyrene ( ) in light weight fill for road embankments. UK design requirements and physical properties of the foam are covered together with two case studies.