火山灰

湖光岩玛珥湖沉积物中的火山灰保存了其原始形貌、原生的沉积和成分特征，是进行岩芯沉积物对比和定年的理想材料之一。

The tephra could not comprise ash layer in the sediments ; however , they were dispersed in the same depth of the core , which is located in27 .

火山灰开始从火山口喷出。

Ash began to erupt from the crater .

气象卫星观测到一个环绕地球的火山灰带。

Weather satellites have observed a ring of volcanic ash girdling the earth

火山灰云层正在菲律宾大范围扩散。

A cloud of volcanic ash is spreading across wide areas of the Philippines

云仙山今天一直在向外喷涌火山灰、气体和火山岩。

Mount Unzen has been spewing out volcanic ash , gas , and rock today

火山灰预计在周二到达苏格兰，在周四可能进入法国和西班牙，E说到。

Ash is expected to reach Scotland on Tuesday and could enter France and Spain on Thursday , Eurocontrol said .

“让人们知道火山灰并没有笼罩整个冰岛，这非常重要，”G说到。

" It is important for people to know that not all of Iceland is covered in ash ," Gudmunsdottir said .

结果表明：随粉煤灰掺量增加，二次火山灰反应生成大量低n（Ca）/n（Si）比的C-S-H凝胶。

The results show that secondary pozzolanic reaction produced more C-S-H with low Ca / Si molar ratio .

纳米SiO2和硅灰的火山灰活性差异的研究

Research on the Difference of Pozzolanic Activity between Nano-SiO_2 and Silica Fume

总之，纳米SiO2的火山灰活性远大于硅粉的火山灰活性。

The pozzolanic activity of nano SiO 2 was much greater than one of silica fume .

估算了粉煤灰火山灰反应所需的最小水泥用量[或Ca（OH）2量]；

The smallest quantity of cement [ or Ca ( OH ) _2 ] that 's needed for the pozzolanic reaction of fly ash was estimated .

结果表明：所采用燃煤灰渣的活性SiO2，Al2O3火山灰反应均符合一级反应动力学模型；

The results show that the pozzolanic reaction of active SiO2 and Al2O3 con-forms to the Class I model of kinetics .

以Ca（OH）2作为胶结充填砂浆中粉煤灰火山灰反应和水泥熟料水化反应的桥梁建立的水化反应动力学模型，基本上与浆体实际水化反应过程相符；

Using Ca ( OH ) 2 as the bridge the fly ash and cement reaction in filling slurry to build the model of hydration reaction kinetics matchs case the true reaction .

同时，通过煅烧高岭石的Si，Al溶出实验和煅烧高岭石-石灰-石膏硬化体的强度实验研究了煅烧煤系高岭石的火山灰活性。

Meanwhile , the volcanic ash activity of calcined coal kaolinite was also studied by means of extraction for Si and Al in calcined kaolinite and the strength of hardening calcined kaolinite-Portlandite-gypsum system .

粉煤灰的火山灰反应生成的也是含水率较低的CSH凝胶。

CSH gel with low water content forms in the pozzolanic reaction of fly ash .

粉煤灰中SiO2在不同碱性条件下的溶出量及与火山灰活性指数的关系

Soluble sio_2 content in fly ash under different alkali conditions and the relationship between the concentration and pozzolanic activity index of fly ash

当细度变化时，同种火山灰材料的Ka和胶砂强度比有着相同的变化规律；

For the same pozzolanic material , the varying trend of K a is similar to that of strength ratio of mortar as fineness was varied .

该法不但可以反映出活性SiO2、Al2O3火山灰反应能力差异，还可得到火山灰反应速率常数和表观活化能等有用的动力学参数。

The new method can differentiate the pozzolanic reactivity of active SiO2 and Al2O3 , and obtain the useful parameters , such as reaction rate constant and activation energy .

交流阻抗谱参数电荷传递电阻Rct和高频电容CHF，可分别反映粉煤灰的火山灰活性和需水量比的特征。

The charge transfer resistance R ct and the HF capacitance C HF represent the characteristic of pozzolanic activity and water requirement ratio of fly ash .

原因是由于硅灰的稀释作用和火山灰效应减少了水泥净浆中Ca（OH）2的量，从而降低了水泥净浆试件在硫酸盐溶液侵蚀下形成的膨胀性钙矾石的量。

The factor is that the Ca ( OH ) 2 in the cement paste is reduced and the formation of expansive ettringite against sulfate attack is decreased yet by the dilute effect and the pozzolanic reaction of silica fume .

沸石凝灰岩的火山灰活性来自凝灰岩中无定性的SiO2和Al2O3。

Structure of zeolite cannot be destroyed by alkalinity in portland cement paste at normal temperature , pozzolanic activity of zeolite_ tuff is from amorphous SiO 2 and Al 2O 3 therein .

硅微粉是冶炼硅铁和金属硅时被烟气带出炉外的无晶形细颗粒，其主要成分是SiO2，具有优越的火山灰性能。

Silicon tiny powder is tiny amorphism grain that is carried out by smoke when we smelt ferrosilicon and metal silicon . Its major composition is SiO2 , and it has superior pozzuolana performance .

运用火山灰效应数值分析方法定量分析了硅灰和石英粉两种主要组分对RPC抗压强度贡献率、强度贡献数值以及两种组分的强度贡献指数。

The quantity analytical method of pozzolanic effect was used in quantitatively analyzing compressive strength contribution rate , strength contribution quantity and strength contribution index of two main compositions including silica fume and crush quartz in RPC .

研究结果表明，采用WH-1活化剂可有效激发煅烧煤矸石潜在的火山灰活性，显著提高煤矸石粉注浆材料早期强度，并可保证后期有较高的强度，能满足注浆材料对强度性能使用的要求。

The experimental results show that the activator can effectively activate gangue activation to increase the initial strength obviously .

结合水泥石强度试验和XRD试验，从火山灰效应、填充效应、水泥水化促进作用和微结构改善作用等方面探讨了三种纳米矿粉在水泥水化硬化过程中的作用机理；

Through strength tests and XRD tests for cemented stone , the paper presents action mechanism of the nanometer materials in the cement hydration and hardening process : pozzolanic effect , filling effect , acceleration action for the cement hydration , and improving action for microstructure .

高岭土经676℃煅烧1h，其质量分数（下同）为74.3%的SiO2和90.32%的Al2O3呈活性状态，火山灰活性最好。

The kaolin calcined at 676 ℃ for 1 h has the optimum pozzolanic activity , and the calcined kaolin with 74.3 % SiO 2 and 90.32 % Al 2O 3 ( all in mass fraction ) are in active form .

NY-2复合激发剂对改善掺粘土火山灰水泥性能的作用

Preparation of NY-2 composite stimulator and its application to pozzolana cement blended with clay

偏高岭土（Metakaolin，简称MK）是一种新型、优质的混凝土矿物掺合料，其火山灰活性和填充效应可优化混凝土的孔结构，改善混凝土的抗渗透性能。

Metakaolin ( MK ) is a new type of high quality concrete mineral admixture of pozzolanic activity and filling effect , which optimize the pore structure remarkably to improve the permeability performance .

硅灰是一种良好的混凝土掺合料，纳米SiO2同样具有火山灰活性，本文运用XRD、SEM、IR和激光粒度仪等现代测试手段研究了纳米SiO2和硅灰的火山灰反应活性差异的原因。

Silica fume is a perfect admixture in concrete and nano-SiO2 has also pozzolanic activity . This paper has studied the reasons of the difference of pozzolanic reaction activity between silica fume and nano-SiO2 by modern testing methods , such as XRD , SEM , IR and laser granulometer .

但英国航空管制机构NATS表示，出于对火山灰威胁的担心，英国6000米以下空域仍基本禁飞。

But British airspace remained largely closed to flights below 6,000 metres owing to ongoing fears about the danger posed by volcanic ash , Nats , the air traffic control body said .