Use of silicon and ferrosilicon industry by-products (silica fume) in cement paste and mortar

With increased environmental awareness, recycling/utilization of industrial byproducts is gaining ground. One such by-product is silica fume (SF), which is byproduct of the smelting process in the silicon and ferrosilicon industry. By-products of the production of silicon metal and the ferrosilicon alloys having silicon contents of 75% or more contain 85-95% non crystalline silica. Silica fume is very useful in the design and development of high quality cement paste/mortar and concrete.This paper presents comprehensive details of the physical, chemical, properties, and its reaction mechanism. It also covers the hydration characteristics, consistency, setting times, workability and compressive strength of cement paste and mortar.     

Utilization of waste foundry sand (WFS) in concrete manufacturing

Due to ever increasing quantities of waste materials and industrial by-products, solid waste management is the prime concern in the world. Scarcity of land-filling space and because of its ever increasing cost, recycling and utilization of industrial by-products and waste materials has become an attractive proposition to disposal. There are several types of industrial by-products and waste materials. The utilization of such materials in concrete not only makes it economical, but also helps in reducing disposal concerns. One such industrial by-product is waste foundry sand (SFS). Waste foundry sand is a by-product of ferrous and nonferrous metal casting industries. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed as waste foundry sand.Published literature has shown that WFS could be used in manufacturing Controlled Low-Strength Materials (CLSM) and concrete. This paper presents an overview of some of the research published on the use of WFS in concrete. Effect of WFS on concrete properties such as compressive strength, splitting tensile strength, modulus of elasticity, freezing-thawing resistance, and shrinkage are presented.     

Utilisation of high volumes of limestone quarry wastes in concrete industry (self-compacting concrete case)

In limestone quarries, considerable amounts of limestone powders are being produced as by-products of stone crushers. High amounts of powders are being collected and utilisation of this by-product is a big problem from the aspects of disposal, environmental pollution and health hazards. In conventional concrete, the introduction of high volumes of limestone quarry dust to concrete mixes is limited due to its negative effects on water demand and strength of concrete. However, these fines can be efficiently utilised as viscosity enhancer particularly in special concrete (like self-compacting concrete—SCC) applications. Thus, the successful utilisation of this quarry dust in SCC could turn this material into a valuable resource.In this paper the usability of a quarry dust limestone powder in self-compacting paste and concrete applications was investigated. In the first part, the physical and mechanical properties of cement pastes incorporating quarry waste limestone powder (QLP) and a powder produced by direct grinding of limestone (PLP) were compared. In the second part, the performance of quarry waste limestone powder in SCC applications were tested and discussed. Results showed that, it is possible to successfully utilise high amounts of quarry waste limestone powder in producing normal-strength SCCs. Among its observed mechanical advantages, employment of quarry waste limestone powders improved the economical feasibility of SCC production.     

利用粉煤灰生产超300^#砼的研究

本文以粉煤灰为主要原料，非蒸养法生产必能优良，超３００＾＃粉煤灰砼，研究了影响粉煤灰胶结料及砼强度的主要因素，找出了获得高度粉煤灰胶结料砼的最佳参数，进行了粉煤灰的性能试验；初步探讨了粉煤灰的砼性能优良的原因，该技术的粉煤灰开辟了一条高价值，大宗利用的有效途径。     

厨房排烟系统的设计

根据厨房排烟净化设备的设计与安装实践,对厨房排烟系统的构成作了介绍,给出了厨房理论排烟风量的计算方法以及集气罩、排风管道及风机的设计选型原则,可以指导饮食业油烟净化器的选型,保证油烟净化器的运行效果。     

Utilisation of high volumes of limestone quarry wastes in concrete industry (self-compacting concrete case)

In limestone quarries, considerable amounts of limestone powders are being produced as by-products of stone crushers. High amounts of powders are being collected and utilisation of this by-product is a big problem from the aspects of disposal, environmental pollution and health hazards. In conventional concrete, the introduction of high volumes of limestone quarry dust to concrete mixes is limited due to its negative effects on water demand and strength of concrete. However, these fines can be efficiently utilised as viscosity enhancer particularly in special concrete (like self-compacting concrete—SCC) applications. Thus, the successful utilisation of this quarry dust in SCC could turn this material into a valuable resource.In this paper the usability of a quarry dust limestone powder in self-compacting paste and concrete applications was investigated. In the first part, the physical and mechanical properties of cement pastes incorporating quarry waste limestone powder (QLP) and a powder produced by direct grinding of limestone (PLP) were compared. In the second part, the performance of quarry waste limestone powder in SCC applications were tested and discussed. Results showed that, it is possible to successfully utilise high amounts of quarry waste limestone powder in producing normal-strength SCCs. Among its observed mechanical advantages, employment of quarry waste limestone powders improved the economical feasibility of SCC production.     

Use of industrial byproducts to filter phosphorus and pesticides in golf green drainage water

Golf courses are vulnerable to phosphate (PO) and pesticide loss by infiltration of the sandy, porous grass rooting media used and through subsurface tile drainage. In this study, an effort was made to remove PO, chlorothalonil, mefenoxam, and propiconazole in a golf green's drainage water with a filter blend comprised of industrial byproducts, including granulated blast furnace slag, cement kiln dust, silica sand, coconut shell-activated carbon, and zeolite. To test this filter media, two 6-h storm events were simulated by repeat irrigation of the golf green after PO and pesticide application. Drainage flows ranged from 0.0034 to 0.6433 L s throughout the course of the simulations. A significant decrease in the chlorothalonil load for the experimental run (with filter media) was observed compared with the control (without filter media) ( < 0.05). In general, percent reductions in chlorothalonil were very high (>80%) near peak flows. In contrast, filter media was not effective in removing PO, mefenoxam, or propiconazole ( > 0.05). Instead, it appears that the filter blend added PO to the effluent above flow rates of 0.037 L s. Overall, flow rate, the amount of filter media used, and contaminant properties may have influenced the filter media's ability to remove contaminants. More research is needed to determine the optimal blend and configuration for the filter media to remove significant amounts of all contaminants investigated.     

Quantitative sustainability assessment of remanufacturing waste reinforcing steel

Construction is a major contributor to the solid waste stream globally and various recycling strategies are being evaluated to recover valuable resources. As a novel strategy, remanufacturing waste reinforcing steel bar (rebar) pieces from concrete waste to produce nails was applied on an industrial scale to prove the technical feasibility, where a group of alternatives were developed based on commercially available industrial machinery. The calculated economic and environmental feasibility values are sufficiently high for industrial application, and the most appropriate remanufacturing technological alternative was identified. The sustainability equation was solved to find the social feasibility and overall remanufacturing sustainability index. Rebar waste remanufacturing has a high triple-bottom-line sustainability index of 0.885. Based on the proposed process, small remanufacturing companies can be developed, thereby aiding employment and human development by earning profit of 1904–8880 USD/day. The findings of this study are beneficial to decision makers in government and industry and are globally relevant because concrete waste is ubiquitous worldwide.     

塑烧管除尘器在冶金精轧线的应用

冶金精轧线烟气烟尘含油含水，采用传统的布袋除尘等方式难以治理。塑烧管具有刚性结构、高过滤效率、压降稳定、疏水疏油性、防静电等特性，适合于治理含油含水的烟气。塑烧管除尘器在冶金精轧线的应用取得了良好的效果。     

LABORATORY TESTS OF EROSION DEPENDENCE ON PROPERTIES OF SOILS AND RAINFALL1

ABSTRACT: One hundred and sixty-two rainfall-induced soil erosion tests were conducted to assist in predicting soil loss and subsequent increase in total suspended solids leaving a highway construction site during a rainfall event. A rainfall simulator and a water flume were constructed for the tests. Soil shear strength, compressive strength, rainfall intensity, and soil bed slope were treated as variables during the experiments. The soil with a higher shear strength resisted soil erosion better than lower strength soils. Soil loss was nearly independent of shear strength at low rainfall intensity but at high intensities, the shear strength was more important in resisting soil loss. Lower soil loss can be expected for cohesive soils if the compressive strength is high.     

Utilization of cement kiln dust (CKD) in cement mortar and concrete—an overview

Solid waste management is one of the major environmental concerns around the world. Cement kiln dust (KKD), also known as by-pass dust, is a by-product of cement manufacturing. The environmental concerns related to Portland cement production, emission and disposal of CKD is becoming progressively significant. CKD is fine-grained, particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the high temperature production of clinker. Cement kiln dust so generated is partly reused in cement plant and landfilled. The beneficial uses of CKD are in highway uses, soil stabilization, use in cement mortar/concrete, CLSM, etc.Studies have shown that CKD could be used in making paste/mortar/concrete. This paper presents an overview of some of the research published on the use of CKD in cement paste/mortar/concrete. Effect of CKD on the cement paste/mortar/concrete properties like compressive strength, tensile strength properties (splitting tensile strength, flexural strength and toughness), durability (Freeze–thaw), hydration, setting time, sorptivity, electrical conductivity are presented. Use of CKD in making controlled low-strength materials (CLSM), asphalt concrete, as soil stabilizer, and leachate analysis are also discussed in this paper.     

浙江省工业油雾管控研究

从浙江省典型涉工业油烟排放的行业入手,包括纺织染整、化学纤维等,分析工业油烟来源、成分、控制技术、排放水平以及管理要求,探讨油雾管控要求和标准制定的必要性,并提出标准制定的思路和建议。     

含油泥砂洗涤法在大港油田的应用

含油泥砂洗涤法可以将含油泥砂中混合的原油、泥、砂回收并重新资源化利用,且处理过程中不产生新的污染物。大港油田应用含油泥砂洗涤法对北部地区产出的含油泥砂进行处理,处理后的泥砂浸出液COD、石油类等指标均能达到GB 8978-1996《污水综合排放标准》一级标准,处理后的泥砂符合JTJ034-2000《公路路面基层施工技术规范》中的石灰工业废渣稳定土抗压强度标准,符合道路修筑用土的抗压强度要求。     

Utilization of cement kiln dust (CKD) in cement mortar and concrete—an overview

Solid waste management is one of the major environmental concerns around the world. Cement kiln dust (KKD), also known as by-pass dust, is a by-product of cement manufacturing. The environmental concerns related to Portland cement production, emission and disposal of CKD is becoming progressively significant. CKD is fine-grained, particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the high temperature production of clinker. Cement kiln dust so generated is partly reused in cement plant and landfilled. The beneficial uses of CKD are in highway uses, soil stabilization, use in cement mortar/concrete, CLSM, etc.Studies have shown that CKD could be used in making paste/mortar/concrete. This paper presents an overview of some of the research published on the use of CKD in cement paste/mortar/concrete. Effect of CKD on the cement paste/mortar/concrete properties like compressive strength, tensile strength properties (splitting tensile strength, flexural strength and toughness), durability (Freeze–thaw), hydration, setting time, sorptivity, electrical conductivity are presented. Use of CKD in making controlled low-strength materials (CLSM), asphalt concrete, as soil stabilizer, and leachate analysis are also discussed in this paper.     

Field investigation of high-volume fly ash pavement concrete

Field investigation of high-volume fly ash (HVFA) concrete in pavement construction was carried out. Test results performed on cores drilled from pavement after 270 days of concrete age showed that use of HVFA results in production of pavement concrete with improvements in: strength; moisture barrier qualities; and abrasive resistance characteristics. These improvements are brought about by the pozzolanic reaction of fly ash with the hydrates of cement that favorably changes the microstructure and interfacial transition zone in the resulting concrete.Use of high volume of fly ash in pavement concrete as partial replacement for cement is estimated to produce major energy and environmental gains and is a practice that is aimed at producing durable and sustainable concrete-based infrastructure. The use of HVFA concrete can significantly economize the construction of concrete pavements and improve the service life of transportation infrastructure.     

Mechanical recycling of EOL concrete into high-grade aggregates

Recycling End of Life (EOL) concrete into high-grade aggregate for new concrete is a challenging prospect for the building sector because of the competing constraints of low recycling process cost and high aggregate product quality. A further complicating factor is that, from the perspective of the environment, there is a strong societal drive to reduce bulk transport of building materials in urban environments, and to apply more in situ recycling technologies for Construction & Demolition Waste. The European C2CA project investigates a combination of smart demolition, grinding of the crushed concrete in an autogenous mill to increase the liberation of cement mortar from the surface of aggregates and a novel dry classification technology called ADR to remove the fines. The feasibility of this recycling process was examined in a demonstration project involving 20,000 tons of EOL concrete from two office towers in Groningen, the Netherlands. Results show that the +4 mm recycled aggregate compares favorably with natural aggregate in terms of workability and the compressive strength of the new concrete, showing 30% higher strength after 7 days.     

广元市饮食业油烟污染现状及防治对策

本文介绍了饮食业油烟污染的危害和油烟净化设备的现状，分析了广元市饮食业油烟污染现状，并提出了饮食业油烟的防治对策。     

城市餐饮业油烟污染状况的分析与对策

通过对本区餐饮油烟污染状况的调查，结果表明多麦子弹位未采用净化施备或存在缺陷不能达标排放，建议环保部门在加强监管，强化市场准入制度，建立清洗队伍同时火力开发高效优质油烟净化设备。     

Characterisation of an unprocessed landfill ash for application in concrete

An investigation was carried out to establish the physical, mechanical and durability characteristics of an unprocessed pulverised fuel ash (PFA) from a former landfill site at the Power Station Hill near Church Village, South Wales, United Kingdom. This was aimed at establishing the suitability of the ash in the construction of the Church Village Bypass (embankment and pavement) and also in concrete to be used in the construction of the proposed highway.Concrete made using binder blends using various levels of PFA as replacement to Portland cement (PC) were subjected to compressive strength tests to establish performance. The concrete was also subjected to sodium sulphate attack by soaking concrete specimens in sulphate solution to establish performance in a sulphatic environment. Strength development up to 365 days for the concrete made with PC–PFA blends as binders (PC–PFA concrete), and 180 days for the PC–PFA paste, is reported.The binary PC–PFA concrete did not show good early strength development, but tended to improve at longer curing periods. The low early strength observed means that PC–PFA concrete can be used for low to medium strength applications for example blinding, low-strength foundations, crash barriers, noise reduction barriers, cycle paths, footpaths and material for pipe bedding.     

饮用水消毒剂二氧化氯研究进展

随着人们对氯消毒副产物毒性的认识,寻求替代消毒荆成为了水处理行业重要的研究课题。本文概述二氧化氯在饮用水消毒应用中的特点,对其在水厂实际应用中的几个热点问题进行研究与分析,最后对其研究发展前景进行了展望。