期刊文献+
共找到71篇文章
< 1 2 4 >
每页显示 20 50 100
Influence of shrinkage-reducing admixture on drying shrinkage and mechanical properties of high-performance concrete 被引量:5
1
作者 Nguyen Quangphu Jiang Linhua +2 位作者 Liu Jiaping Tian Qian Do Tienquan 《Water Science and Engineering》 EI CAS 2008年第4期67-74,共8页
High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.... High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.2-0.4, so volume changes of concrete as a result of drying, chemical reactions, and temperature change cannot be avoided. For these reasons, shrinkage and cracking are frequent phenomena. It is necessary to add some types of admixture for reduction of shrinkage and cracking of HPC. This study used a shrinkage-reducing admixture (SRA) for that purpose. Concrete was prepared with two different mW/mB (0.22 and 0.40) and four different mass fractions of SRA to binder (w(SRA) = 0%, 1%, 2%, and 4%). The mineral admixtures used for concrete mixes were: 25% fly ash (FA) and 25% slag by mass of binder for the mixture with mW/mB = 0.40, and 15% silica fume (SF) and 25% FA for the mixture with mW/mB = 0.22. Tests were conducted on 24 prismatic specimens, and shrinkage strains were measured through 120 days of drying. Compressive strength, splitting strength, and static modulus of elasticity were also determined. The results show that the SRA effectively reduces some mechanical properties of HPC. The reductions in compressive strength, splitting tensile strength, and elastic modulus of the concrete were 7%-24%, 9%-19%, and 5%-12%, respectively, after 90 days, compared to concrete mixtures without SRA. SRA can also help reduce drying shrinkage of concrete. The shrinkage strains of HPC with SRA were only as high as 41% of the average free shrinkage of concrete without SRA after 120 days of drying. 展开更多
关键词 high-performance concrete shrinkage-reducing admixture compressive strength elastic modulus splitting tensile strength drying shrinkage
下载PDF
Effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete 被引量:6
2
作者 Fareed Ahmed Memon Muhd Fadhil Nuruddin Nasir Shafiq 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第2期205-213,共9页
The effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete (SCGC) was investigated in this paper. The work focused on the concrete mixes with a fixed water-to... The effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete (SCGC) was investigated in this paper. The work focused on the concrete mixes with a fixed water-to-geopolymer solid (W/Gs) ratio of 0.33 by mass and a constant total binder content of 400 kg/m3. The mass fractions of silica fume that replaced fly ash in this research were 0wt%, 5wt%, 10wt%, and 15wt%. The workability-related fresh properties of SCGC were assessed through slump flow, V-funnel, and L-box test methods. Hardened concrete tests were limited to compressive, splitting tensile and flexural strengths, all of which were measured at the age of 1, 7, and 28 d after 48-h oven curing. The results indicate that the addition of silica fume as a partial replacement of fly ash results in the loss of workability; nevertheless, the mechanical properties of hardened SCGC are significantly improved by incorporating silica fume, especially up to 10wt%. Applying this percentage of silica fume results in 4.3% reduction in the slump flow; however, it increases the compressive strength by 6.9%, tensile strength by 12.8% and flexural strength by 11.5%. 展开更多
关键词 geopolymer concrete silica fume fresh properties compressive strength tensile strength flexural strength
下载PDF
Fundamental Study on Alkali-Activated Slag System with Sodium Carbonate or Calcium Hydroxide
3
作者 Seunghyun Na Wenyan Zhang +2 位作者 Yuichi Ichikawa Masaya Komatsu Aoi Takemura 《Journal of Materials Science and Chemical Engineering》 2024年第6期55-70,共16页
Cement as a building material, has high fluidity, compressive strength, and durability, but carbon dioxide emissions during cement production are a major problem. As one of the countermeasures, alkali-activated cement... Cement as a building material, has high fluidity, compressive strength, and durability, but carbon dioxide emissions during cement production are a major problem. As one of the countermeasures, alkali-activated cement using blast furnace slag powder with alkaline stimulants is considered to be a very promising solution for reducing carbon dioxide emissions, but there is a lack of information about the fundamental properties of alkali-activated materials. This study presents an experimental investigation of the fundamental properties of an alkali-activated slag system with sodium carbonate (NC) and calcium hydroxide (CH). The effects of calcium sulfo-aluminate (CSA) and shrinkage reducing agent (SRA) on the properties of blast furnace slag (BFS) based alkali-activated mixture were also investigated. In the experiments, fundamental characteristics including compressive strength, drying shrinkage, and water penetration tests of mortar were evaluated. Porosity, pH, and ignition loss were measured to verify the effectiveness of the materials. The experimental investigation revealed that the compressive strength was increased with the increasing replacement rates of NC in the BFS mortar, and in the case of water to BFS ratio of 0.45 with sodium carbonation addition contents 10 wt.%, the compressive strength for 28 days of curing reaches more than 50 MPa. Low water to BFS ratio and higher addition ratio of NC had a positive effect on the compressive strength development of mortar. Incorporating NC into BFS would affect the decrease in porosity and increase in ignition loss, leading to higher compressive strength. There was a negligible change to the compressive strength, porosity, pH, and ignition loss of BFS samples made with CH, thus, the addition rates of CH to BFS have no or little significant effect on the fundamental properties of alkali-activated cement. From the results of drying shrinkage and water penetration tests, the addition of NC and CH only to BFS exhibited poor drying shrinkage and water penetration characteristics. However, these problems may be overcome due to the use of CSA or SRA in the alkali-activated system made with NC or CH. 展开更多
关键词 Alkali-Activated Cement compressive strength drying shrinkage Water Penetration Characteristic
下载PDF
地聚物混凝土干燥收缩性能及活性氧化镁补偿收缩研究 被引量:2
4
作者 张海霞 董昊 《硅酸盐通报》 CAS 北大核心 2024年第1期219-226,共8页
制备粉煤灰-矿渣基地聚物混凝土,并进行地聚物混凝土28 d抗压强度和干燥收缩测试,探究分析活性氧化镁含量、水玻璃模数、碱当量和矿渣含量对其抗压强度和干燥收缩的影响机理。结果表明:随着活性氧化镁掺量增大,地聚物混凝土28 d抗压强... 制备粉煤灰-矿渣基地聚物混凝土,并进行地聚物混凝土28 d抗压强度和干燥收缩测试,探究分析活性氧化镁含量、水玻璃模数、碱当量和矿渣含量对其抗压强度和干燥收缩的影响机理。结果表明:随着活性氧化镁掺量增大,地聚物混凝土28 d抗压强度下降,干燥收缩变形显著减小;与0%(质量分数,下同)活性氧化镁混凝土相比,掺量为3%、6%和9%时混凝土28 d抗压强度分别下降8.0%、8.2%和18.2%,干燥收缩分别减小21.5%、26.4%和38.2%,此外,当活性氧化镁掺量为3%和6%时,不仅有效补偿了干燥收缩,且抗压强度损失较小;随着水玻璃模数升高,地聚物混凝土28 d抗压强度和干燥收缩变形增大;随着碱当量升高,地聚物混凝土28 d抗压强度下降、干燥收缩变形增大;随着矿渣含量增加,地聚物混凝土28 d抗压强度增大、干燥收缩变形减小。综合考虑抗压强度及收缩的要求,建议实际应用中选择高活性、大掺量氧化镁,掺量宜控制在3%~6%。 展开更多
关键词 地聚物混凝土 粉煤灰-矿渣基 活性氧化镁 干燥收缩 抗压强度
下载PDF
菱镁矿尾矿粉对水泥砂浆力学与收缩性能研究 被引量:1
5
作者 温永钦 卢金山 +1 位作者 王禄彤 姜婷婷 《新型建筑材料》 2024年第2期59-62,共4页
为改善商品混凝土收缩严重的现象,通过外掺菱镁矿尾矿粉,研究了菱镁矿尾矿粉掺量及细度对水泥砂浆抗压、抗折强度及收缩性能的影响。试验结果表明:随着菱镁矿尾矿粉掺量的增加,水泥砂浆的抗压和抗折强度均呈先提高后降低的趋势,掺量为10... 为改善商品混凝土收缩严重的现象,通过外掺菱镁矿尾矿粉,研究了菱镁矿尾矿粉掺量及细度对水泥砂浆抗压、抗折强度及收缩性能的影响。试验结果表明:随着菱镁矿尾矿粉掺量的增加,水泥砂浆的抗压和抗折强度均呈先提高后降低的趋势,掺量为10%时28 d抗压、抗折强度比不掺时分别提高20.6%、19.8%;对水泥砂浆干燥收缩率影响大小顺序为:菱镁矿尾矿粉细度>菱镁矿尾矿粉掺量>水胶比,水胶比为0.35、菱镁矿尾矿粉细度为500目,菱镁矿尾矿粉掺量为9%时补偿水泥砂浆收缩效果最好。 展开更多
关键词 菱镁矿尾矿粉 抗压强度 抗折强度 干燥收缩率
下载PDF
不同配合比的HECC力学与干缩性能试验研究 被引量:1
6
作者 胡伟 李家正 +1 位作者 石妍 卢晓春 《人民长江》 北大核心 2024年第4期222-229,共8页
水工超高韧性水泥基复合材料(HECC),具有中等强度、低弹性模量、较强的热稳定性、可控的裂缝宽度及较宽泛的原材料来源等特性,由于其中无粗骨料、胶凝材料用量高,其体积变形明显高于普通水工混凝土,因此必须合理控制体积稳定性。为探寻... 水工超高韧性水泥基复合材料(HECC),具有中等强度、低弹性模量、较强的热稳定性、可控的裂缝宽度及较宽泛的原材料来源等特性,由于其中无粗骨料、胶凝材料用量高,其体积变形明显高于普通水工混凝土,因此必须合理控制体积稳定性。为探寻不同因素对HECC干缩及力学性能的影响及其发展规律,开展了不同水胶比、纤维掺量、粉煤灰以及硅灰掺量下的HECC流动性能、抗压抗折强度和干缩性能试验,并利用SEM对水化产物进行观察。结果表明:在用水量一定的情况下,水胶比由0.25增至0.35,试样的28 d抗压强度、抗折强度和干燥收缩分别降低17.3%,9.7%和20.5%;纤维掺量显著影响HECC抗折强度,掺量2.0%比1.0%时的抗折强度高30.0%,但对抗压强度与干缩性能影响不大;粉煤灰掺量对HECC抗压和抗折强度影响较大,且抗压抗折强度随着粉煤灰的增大而逐渐减小,掺量60%时对应的抗压强度和抗折强度较40%时分别降低30.4%和18.2%,粉煤灰掺量增加能够大幅度降低HECC干燥收缩,掺量60%时的干缩率较40%掺量时降低23.5%;硅灰能提升HECC早期抗压抗折强度,且随着硅灰掺量的增加趋势逐渐变缓,但硅灰对HECC的干缩不利,会增大HECC干燥收缩,掺6%时干缩率较基准组增长13.6%。 展开更多
关键词 HECC 干燥收缩 抗压强度 抗折强度
下载PDF
溶胶型纳米SiO_(2)和减水剂对粉煤灰-矿渣地聚物性能的影响 被引量:1
7
作者 李新宇 彭金财 +3 位作者 段立伟 王武 李伟宇 许福 《市政技术》 2024年第2期21-26,114,共7页
地聚物是一种有望替代普通硅酸盐水泥以降低土木工程行业碳排放的新型绿色环保胶凝材料。然而,粉煤灰-矿渣地聚物存在流动性差、干燥收缩大等问题,限制了其在工程领域的进一步推广应用。因此,通过试验研究了复掺减水剂和溶胶型纳米SiO_... 地聚物是一种有望替代普通硅酸盐水泥以降低土木工程行业碳排放的新型绿色环保胶凝材料。然而,粉煤灰-矿渣地聚物存在流动性差、干燥收缩大等问题,限制了其在工程领域的进一步推广应用。因此,通过试验研究了复掺减水剂和溶胶型纳米SiO_(2)对粉煤灰-矿渣地聚物工作性能、干燥收缩和抗压强度的影响,并分析了相关机理。试验结果表明,对于粉煤灰-矿渣质量比为7∶3的体系,与未掺加溶胶型纳米SiO_(2)和减水剂的粉煤灰-矿渣地聚物相比,当溶胶型纳米SiO_(2)和减水剂掺量分别为0.2%和1.0%时,粉煤灰-矿渣地聚物流动度从176 mm增大至198 mm,27 d干燥收缩降低了31.2%,3、7、28 d抗压强度分别提高了52.2%、24.5%、32.3%;溶胶型纳米SiO_(2)和减水剂复掺增加了参与反应的活性硅源,形成了更多的N-A-S-H和C-(A)-S-H凝胶产物,使得硬化后材料的结构更加致密。该研究可为粉煤灰-矿渣地聚物的进一步研究和应用提供参考。 展开更多
关键词 地聚物 纳米SiO_(2) 减水剂 干燥收缩 抗压强度
下载PDF
酸激发磷石膏地聚合物胶凝材料基本物理性能研究
8
作者 蔡林 徐闫 +1 位作者 刘杰胜 谭晓明 《山东商业职业技术学院学报》 2024年第1期111-116,共6页
以原状磷石膏、水泥、偏高岭土等为主要原料,磷酸或乙酸为激发剂,制备了酸激发磷石膏胶凝材料并探究其基本物理力学性能,研究了酸激发剂的种类及掺量对胶凝材料抗压性能和抗折性能的影响。研究结果表明:磷石膏、偏高岭土、水泥的质量比... 以原状磷石膏、水泥、偏高岭土等为主要原料,磷酸或乙酸为激发剂,制备了酸激发磷石膏胶凝材料并探究其基本物理力学性能,研究了酸激发剂的种类及掺量对胶凝材料抗压性能和抗折性能的影响。研究结果表明:磷石膏、偏高岭土、水泥的质量比为45∶15∶40,掺加量为1-5%的磷酸或乙酸,制备的胶凝材料具有较好的抗压抗折性能;掺加量为4%的磷酸制备的胶凝材料28天龄期的抗压强度达到了30.97MPa,抗折强度3.64 MPa;掺加量为4%的乙酸制备的胶凝材料28天龄期的抗压强度19.03MPa,抗折强度达到了4.08 MPa;在自然养护条件下,磷酸激发的磷石膏胶凝材料的激发效果优于乙酸。 展开更多
关键词 磷石膏 地聚合物 酸性激发剂 抗压强度 抗折强度
下载PDF
粉煤灰对新型超早强磷酸盐修补材料的改性研究
9
作者 周跃孝 李硕 +1 位作者 赵顺义 唐春平 《重庆建筑》 2024年第9期43-45,共3页
在磷酸盐修补材料中加入粉煤灰,可有效地改善其性能。试验研究了粉煤灰掺量对磷酸盐修补材料凝结时间、强度及收缩性能的影响。结果表明,掺入适量粉煤灰可以延缓凝结时间,但随着粉煤灰掺量的增加,强度有所降低,可减少磷酸盐修补材料的... 在磷酸盐修补材料中加入粉煤灰,可有效地改善其性能。试验研究了粉煤灰掺量对磷酸盐修补材料凝结时间、强度及收缩性能的影响。结果表明,掺入适量粉煤灰可以延缓凝结时间,但随着粉煤灰掺量的增加,强度有所降低,可减少磷酸盐修补材料的干缩。 展开更多
关键词 磷酸盐 粉煤灰 凝结时间 抗压强度 抗折强度 干缩
下载PDF
镍渣对粉煤灰基地质聚合物收缩性能的影响
10
作者 齐道正 王炳监 +1 位作者 陈登 李莉 《金属矿山》 CAS 北大核心 2024年第2期276-280,共5页
镍渣是镍冶炼过程中排出的工业固废,以镍渣为原料制备地质聚合物,既提高了地质聚合物的绿色环保属性,更有助于促进镍铁合金工业的可持续发展。向粉煤灰基地质聚合物中掺入镍渣,并考察镍渣掺量对硬化体收缩性能的影响。结果表明,镍渣掺量... 镍渣是镍冶炼过程中排出的工业固废,以镍渣为原料制备地质聚合物,既提高了地质聚合物的绿色环保属性,更有助于促进镍铁合金工业的可持续发展。向粉煤灰基地质聚合物中掺入镍渣,并考察镍渣掺量对硬化体收缩性能的影响。结果表明,镍渣掺量为25%时不仅提高了地质聚合物的抗压强度,同时有助于降低自收缩和干燥收缩。镍渣反应活性较低,掺入粉煤灰基地质聚合物中会减缓碱激发反应进程,进而降低硬化体自收缩。另一方面,镍渣颗粒在硬化体中发挥微骨料作用,掺入后有助于降低地质聚合物孔隙率,既提高了硬化体的抗压强度,同时抑制干燥过程中的水分蒸发并降低了干燥收缩。 展开更多
关键词 地质聚合物 镍渣 收缩 抗压强度 孔结构
下载PDF
活性粉末混凝土力学与收缩特性研究
11
作者 李金翔 《江西建材》 2024年第7期37-39,共3页
文中从混凝土抗压强度、抗折强度、干燥收缩性能等方面入手,系统探讨了超细二氧化硅粉掺量对活性粉末混凝土力学性能和收缩特性的影响。试验表明,10%的二氧化硅粉掺量能显著提升活性粉末混凝土的抗压和抗折强度,并有效减缓收缩应变的增... 文中从混凝土抗压强度、抗折强度、干燥收缩性能等方面入手,系统探讨了超细二氧化硅粉掺量对活性粉末混凝土力学性能和收缩特性的影响。试验表明,10%的二氧化硅粉掺量能显著提升活性粉末混凝土的抗压和抗折强度,并有效减缓收缩应变的增长。龄期为90 d时,掺入10%超细二氧化硅粉的混凝土与掺量为0的混凝土相比,其抗压强度提高了8.81%,抗折强度提高了7.59%,收缩率降低了11.27%。 展开更多
关键词 超细二氧化硅粉 抗压强度 抗折强度 干燥收缩
下载PDF
路圣-水泥综合稳定弃土路用性能研究
12
作者 员康锋 《山西交通科技》 2024年第4期29-32,共4页
通过掺入路圣材料制备了路圣-水泥综合稳定弃土(简称路圣-水泥土)试验试件,进行了路圣-水泥土的无侧限抗压强度、弹性模量、弯拉强度、疲劳寿命等试验,并与相应的水泥稳定弃土(简称水泥土)试验进行了结果对比分析。研究结果表明:路圣材... 通过掺入路圣材料制备了路圣-水泥综合稳定弃土(简称路圣-水泥土)试验试件,进行了路圣-水泥土的无侧限抗压强度、弹性模量、弯拉强度、疲劳寿命等试验,并与相应的水泥稳定弃土(简称水泥土)试验进行了结果对比分析。研究结果表明:路圣材料可显著提高水泥土的无侧限抗压强度、弹性模量和弯拉强度,且对后期无侧限抗压强度提升效果明显;在同等应力水平下,路圣材料可以大幅提高水泥土的疲劳寿命;路圣-水泥土与水泥土相比,冻融循环对其强度影响较小,在冻融循环过程中,路圣材料使得水泥土内部颗粒之间连结强度变得更高;在相同时间水平下,路圣-水泥土的收缩变形量最小,可见路圣材料可以减小收缩量。 展开更多
关键词 路圣-水泥土 无侧限抗压强度 弹性模量 弯拉强度 疲劳寿命 收缩变形量 稳定弃土
下载PDF
Influence of Thermally Treated Flue Gas Desulfurization(FGD) Gypsum on Performance of the Slag Powder Concrete 被引量:2
13
作者 GUO Xiaolu SHI Huisheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第6期1122-1127,共6页
The feasibility of flue gas desulphurization (FGD) as concrete admixture was studied. A combined concrete admixture of the thermally-treated FGD gypsum and slag powder was explored. The FGD gypsum was roasted at 200... The feasibility of flue gas desulphurization (FGD) as concrete admixture was studied. A combined concrete admixture of the thermally-treated FGD gypsum and slag powder was explored. The FGD gypsum was roasted at 200℃ for 60 min and then mixed with the slag powder to form FGD gypsum-slag powder combined admixture in which the SO3 content was 3.5wt%. Cement was partially and equivalently replaced by slag powder alone or FGD gypsum-slag powder, at concentration of 25wt%, 40wt%, and 50wt%, respectively. The setting times, hydration products, total porosity and pore size distributions of the paste were determined. The compressive strength and drying shrinkage of cement mortar and concrete were also tested. The experimental results show that, in the presence of FGD gypsum, the setting times are much slower than those of pastes in the absence of FGD gypsum. The combination of FGD gypsum and slag powder provides synergistic benefits above that of slag powder alone. The addition of FGD gypsum provides benefit by promoting ettringite formation and forms a compact microstructure, increasing the compressive strength and reduces the drying shrinkage of cement mortar and concrete. 展开更多
关键词 flue gas desulfurization (FGD) gypsum slag powder compressive strength drying shrinkage MORTAR CONCRETE
下载PDF
Fresh and hardened properties of high-strength concrete incorporating byproduct fine crushed aggregate as partial replacement of natural sand 被引量:1
14
作者 Dammika P.K.WELLALA Ashish Kumer SAHA +1 位作者 Prabir Kumar SARKER Vinod RAJAYOGAN 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2021年第1期124-135,共12页
This paper presents the fresh and hardened properties of high-strength concrete comprising byproduct fine crushed aggregates(FCAs)sourced from the crushing of three different types of rocks,namely granophyre,basalt,an... This paper presents the fresh and hardened properties of high-strength concrete comprising byproduct fine crushed aggregates(FCAs)sourced from the crushing of three different types of rocks,namely granophyre,basalt,and granite.The lowest void contents of the combined fine aggregates were observed when 40%to 60%of natural sand is replaced by the FCAs.By the replacement of 40%FCAs,the slump and bleeding of concrete with a water-to-cement ratio of 0.45 decreased by approximately 15%and 50%,respectively,owing to the relatively high fines content of the FCAs.The 28 d compressive strength of concrete was 50 MPa when 40%FCAs were used.The slight decrease in tensile strength from the FCAs is attributed to the flakiness of the particles.The correlations between the splitting tensile and compressive strengths of normal concrete provided in the AS 3600 and ACI 318 design standards are applicable for concrete using the FCAs as partial replacement of sand.The maximum 56 d drying shrinkage is 520 microstrains,which is significantly less than the recommended limit of 1000 microstrains by AS 3600 for concrete.Therefore,the use of these byproduct FCAs can be considered as a sustainable alternative option for the production of high-strength green concrete. 展开更多
关键词 fine crushed aggregates quarry dust compressive strength splitting tensile strength drying shrinkage
原文传递
Size Variation of Palm Kernel Shells as Replacement of Coarse Aggregate for Lightweight Concrete Production
15
作者 Humphrey Danso Frank Appiah-Agyei 《Open Journal of Civil Engineering》 2021年第1期153-165,共13页
The utilization of palm kernel shells (PKS) as an alternative to conventional materials for construction is desirable to promote sustainable development. The purpose of this study is to investigate the properties of l... The utilization of palm kernel shells (PKS) as an alternative to conventional materials for construction is desirable to promote sustainable development. The purpose of this study is to investigate the properties of lightweight concrete produced with different sizes of PKS of 6, 8, 10, 12 mm and mix (consisting of 25% each of the four sizes). RPK sizes were used to replace coarse aggregate in the concrete and cured for 7, 14, 21 and 28 days. The tests performed on the concrete are dry density, compressive strength, flexural strength, EDS and SEM. It was revealed that the densities of the concrete specimens were all less than 2000 kg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, which implies that the PKS concrete satisfied the requirement of lightweight concrete for structural application. The compressive strength of the 12 mm PKS concrete specimens at 28-day of curing was 10.2 MPa which was 4% to 15.9% better than the other PKS sizes concrete. The flexural strength of the 12 mm PKS concrete specimens at 28-day of curing was 2.85 MPa which was also 3.2% to 57.07% better than the other PKS sizes concrete. It was also revealed by the SEM analysis that there was a good bond between the palm kernel shells and the mortar. A high calcium-silicate content was found in the concrete which resulted in a Ca/Si ratio of 1.26 and Al/Si ratio of 0.11. The study therefore concludes that size variations of PKS as replacement of coarse aggregate have an influence on the properties of the lightweight concrete and recommends 12 mm PKS for use by construction practitioners for lightweight concrete structural application</span></span></span><span style="font-family:Verdana;">. 展开更多
关键词 compressive strength Dry Density flexural strength Lightweight Concrete Palm Kernel Shell
下载PDF
粉煤灰基地质聚合物力学性能及碱渣改性机理 被引量:29
16
作者 刘春原 赵献辉 +2 位作者 朱楠 刘宇飞 庞云泽 《硅酸盐通报》 CAS CSCD 北大核心 2017年第2期679-685,691,共8页
为探索粉煤灰基地质聚合物的力学特性,通过12组胶砂试样的抗折和抗压强度研究NaOH掺量、养护条件、龄期和碱渣掺量对力学性能的影响,对比不同因素下试样胶砂表面孔隙特征,分析了碱渣对粉煤灰基地质聚合物体系的改性机理。结果表明:1.NaO... 为探索粉煤灰基地质聚合物的力学特性,通过12组胶砂试样的抗折和抗压强度研究NaOH掺量、养护条件、龄期和碱渣掺量对力学性能的影响,对比不同因素下试样胶砂表面孔隙特征,分析了碱渣对粉煤灰基地质聚合物体系的改性机理。结果表明:1.NaOH溶液过剩使强度降低;高温养护能提高强度;粉煤灰基地质聚合物的养护不需要太大的湿度。2.碱渣掺量小于27%时,对粉煤灰-NaOH体系强度有显著的改性作用。CaCO_3增大溶液碱性,减小胶砂流动性,影响地质聚合物的微观结构,有效改善体系收缩程度。3.可溶性含钙组分中Ca^(2+)参与生成C-SH凝胶,与地质聚合物协同作用提高胶结性,减小孔隙的连通性。 展开更多
关键词 粉煤灰基地质聚合物 抗折强度 抗压强度 影响因素 碱渣改性机理
下载PDF
马尾松人工林木材主要材性家系间的变异 被引量:9
17
作者 李清芸 林金国 +2 位作者 卞丽萍 王晓娴 巫其荣 《西北林学院学报》 CSCD 北大核心 2015年第5期209-213,共5页
对25个家系马尾松人工林木材主要物理力学性能进行测定和比较分析。结果表明,马尾松人工林木材气干密度由大到小居前五位的家系依次为378、329、317、341、335,顺纹抗压强度值由大到小居前5位的家系依次是335、350、372、325、329;家系... 对25个家系马尾松人工林木材主要物理力学性能进行测定和比较分析。结果表明,马尾松人工林木材气干密度由大到小居前五位的家系依次为378、329、317、341、335,顺纹抗压强度值由大到小居前5位的家系依次是335、350、372、325、329;家系341和350马尾松人工林木材体积干缩系数和差异干缩均较小,尺寸性稳定均较好。方差分析表明,家系对马尾松人工林木材主要物理力学性能影响显著。多重比较分析表明,马尾松人工林木材气干密度、体积干缩系数、差异干缩以及顺纹抗压强度各家系间大都表现为差异显著或极显著。家系335、341、350、378可作为马尾松人工林木材品质选育的优良材料。 展开更多
关键词 马尾松 家系 气干密度 干缩性 顺纹抗压强度
下载PDF
减缩剂和HCSA膨胀剂对UHPC力学性能和收缩性能的影响 被引量:18
18
作者 龚建清 罗鸿魁 +4 位作者 张阳 龚啸 谢泽酃 吴五星 戴远帆 《材料导报》 EI CAS CSCD 北大核心 2021年第8期42-48,63,共8页
本研究主要对比了减缩剂和高性能混凝土膨胀剂(HCSA)单掺以及复掺时,对超高性能混凝土(UHPC)强度、收缩性能的影响。结果显示,减缩剂会延缓水泥水化,延长水泥凝结时间,不利于UHPC早期强度的发展。随着减缩剂掺量(0%~2%,质量分数)增加,U... 本研究主要对比了减缩剂和高性能混凝土膨胀剂(HCSA)单掺以及复掺时,对超高性能混凝土(UHPC)强度、收缩性能的影响。结果显示,减缩剂会延缓水泥水化,延长水泥凝结时间,不利于UHPC早期强度的发展。随着减缩剂掺量(0%~2%,质量分数)增加,UHPC的自收缩降低,当减缩剂掺量为0.5%时可有效降低UHPC的干燥收缩。而HCSA膨胀剂缩短UHPC的凝结时间,早期强度的发展快;HCSA膨胀剂具有降低UHPC内部有害孔数量、减小总孔隙率的作用,能够降低UHPC的自收缩和干燥收缩;但HCSA膨胀剂过量时,无法获得足够的水分参与反应,且有破坏UHPC结构的风险。减缩剂和HCSA膨胀剂复掺时,UHPC的抗压、抗折强度均大于单掺减缩剂时的强度,且小于单掺HCSA膨胀剂时的强度。2%减缩剂和10%HCSA膨胀剂复掺对UHPC收缩的抑制作用最好,同时UHPC具有较高的力学性能。 展开更多
关键词 超高性能混凝土 减缩剂 HCSA膨胀剂 抗压强度 抗折强度 自收缩 干燥收缩
下载PDF
玻璃纤维与聚丙烯纤维混凝土性能的对比试验 被引量:18
19
作者 丁一宁 杨楠 《水利水电科技进展》 CSCD 北大核心 2007年第1期24-26,共3页
设计了常温下普通强度等级混凝土和高性能自密实混凝土的试验,对比分析了玻璃纤维和聚丙烯纤维在掺量一致(0.5kg/m3和1.0kg/m3)、长度相近的条件下对混凝土性能的影响。试验表明,玻璃纤维和聚丙烯纤维均能提高普通混凝土的抗折强度和劈... 设计了常温下普通强度等级混凝土和高性能自密实混凝土的试验,对比分析了玻璃纤维和聚丙烯纤维在掺量一致(0.5kg/m3和1.0kg/m3)、长度相近的条件下对混凝土性能的影响。试验表明,玻璃纤维和聚丙烯纤维均能提高普通混凝土的抗折强度和劈拉强度,但玻璃纤维的效果优于聚丙烯纤维。玻璃纤维和聚丙烯纤维对高性能自密实混凝土抗压强度和抵抗早龄期自由收缩的能力的影响区别不明显,但均能改善高性能自密实混凝土受压时的脆性破坏特征。 展开更多
关键词 玻璃纤维 聚丙烯纤维 纤维混凝土 抗折强度 劈拉强度 抗压强度 自由收缩
下载PDF
矿渣-粉煤灰地聚物固化淤泥力学性能和路用性能研究 被引量:17
20
作者 杨振甲 何猛 +4 位作者 吴杨 史钰鹏 孙亮 潘竹 张默 《硅酸盐通报》 CAS 北大核心 2022年第2期693-703,724,共12页
为实现河底淤泥的资源化处置,常采用水泥等胶凝材料固化淤泥提高承载力作为路基材料。传统固化材料能耗大、碳排放量高。为开发可持续性固化材料,本研究采用矿渣-粉煤灰二元地聚物固化淤泥,研究其力学性能及路用性能。通过研究Si/Al摩... 为实现河底淤泥的资源化处置,常采用水泥等胶凝材料固化淤泥提高承载力作为路基材料。传统固化材料能耗大、碳排放量高。为开发可持续性固化材料,本研究采用矿渣-粉煤灰二元地聚物固化淤泥,研究其力学性能及路用性能。通过研究Si/Al摩尔比、Na/Al摩尔比对地聚物凝结时间和抗压强度的影响规律,确定地聚物配合比设计。依据优化配合比固化淤泥,研究地聚物掺量、养护龄期对固化淤泥力学性能的影响,并对固化淤泥进行水稳性、加州承载比、干缩和温缩试验,以评估其路用性能;采用扫描电镜和X射线衍射等试验方法对固化淤泥进行微观分析,揭示其固化机制。试验结果表明,矿渣-粉煤灰基地聚物地质聚合产物为无定形地聚物凝胶、水化硅酸钙、水化铝酸钙等,增强了土颗粒之间的胶结并且填充了孔隙,提高了固化淤泥的力学性能和路用性能。研究结果为地聚物固化淤泥土工程应用提供了实验基础。 展开更多
关键词 固化淤泥 矿渣-粉煤灰地聚物 无侧限抗压强度 水稳性 干缩性 温缩性 固化机理 路基材料
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部