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Over the last few years environmental problems have caught the particular attention of the public, and this has led to various investigations that attempt to study and solve the focal point that cause environmental contamination. The main aim of this study is to determine the presence of polluting elements incorporated into the manufacture of cements and concretes, which might have a noxious effect on health. One way to incorporate this kind of element is by the incorporation of industrial by-products into cement. This paper studies the leaching of trace elements from copper slag, when this by-product is incorporated into cement mortars. A dynamic leaching test has been applied, in which the specimen is studied fully immersed in drinking water. To develop this test has been designed three tanks (reference drinking water, reference mortar and blended mortar), where the samples are continuously flowing. The quantification of leaching elements from the copper slag blended mortar is carried out to different contact time.

The development of self-compacting concrete is considered as a milestone achievement in concrete technology due to several advantages. In order to be self-compactable the fresh concrete must show high fluidity besides good cohesiveness. For the purpose of evaluating these properties, several concrete mixtures were prepared with a water to cement ratio of 0.45 in the presence of an acrylic based superplasticizer at a dosage ranging from 1% to 2% by weight of very fine material fraction (passing the sieve ASTM n° 100 of 150 µm). Either limestone powder or fly ash or recycled aggregate powder (that is a powder obtained from the rubble recycling process) were used as mineral addition, in order to assure adequate rheological properties, in terms of cohesiveness, in the self-compacting concretes. Preliminary rheological tests were carried out on cement pastes containing these mineral additions. In some cases, recycled instead of natural aggregate was used by subtituting either the coarse or the fine aggregate fraction. The fresh concrete properties were evaluated through the slump flow, the L-box test and segregation resistance. Compressive strength was measured on hardened concretes at 1, 3, 7 and 28 days of wet curing.

In 2004, the Canadian Centre for Mineral and Energy Technology (CANMET), in association with the American Concrete Institute, the Electric Power Research Institute, Palo Alto, CA, UWM Center for By-Products Utilization, Milwaukee, WI, and several other organizations in Canada, sponsored the Eighth CANMET/ACI International Conference on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete. The conference was held in Las Vegas, Nevada, U.S.A., May 23-29, 2004. The proceedings of the conference containing 56 refereed papers from more than 20 countries were published as ACI Symposiuml Publication SP-221. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP221

This paper discusses the physical properties and leachate characteristics of a newly developed CLSM (Controlled Low Strength Materials) with a special type of cement as well as aggregate made from municipal solid waste. Eco-Cement, so-called in Japan, is the latest green cement made primarily from municipal refuse incineration ash and sewage sludge. Aggregate used in this paper was also made from the slag of municipal solid waste incinerator. High-volume off-specification fly ash was also used. This new type of green CLSM will he a promising sustainable material to reduce CO2 emissions. Test results showed an adequate strength development and reasonable flowability, especially when the mixture proportion is carefully designed. The leachate characteristics of this new CLSM are evaluated in this paper. Two types of standard tests showed acceptable leachate levels. From these tests results it was confirmed that a wide range of municipal solid waste may be applicable for the materials of the new green CLSM.

The influence of some pozzolanic additions—such as silica fume, fly ash and ultra-fine amorphous colloidal silica (UFACS)—on the performance of superplasticized concrete was studied. Superplasticized mixtures in form of flowing (slump of 230 mm) or self-compacting concretes (slump flow of 735 mm) were manufactured all with a water-cement ratio as low as 0.44, in order to produce high-performance concretes (HPC). They were cured at room temperature (20°C) or steam-cured at 65°C in order to simulate the manufacturing of pre-cast members. Concretes with ternary combinations of silica fume (15-20 kg/m3), fly ash (30-40 kg/m3) and UFACS (5-8 kg/m3) perform better—in terms of strength and durability—than those with fly ash alone (60 kg/m3) and approximately as those with silica fume alone (60 kg/m3). Due to the reduced avail-ability of silica fume on the market, these ternary combinations can reduce by 60-70% the needed amount of silica fume for each pre-cast HPC element at a given performance level. Moreover, at later ages the strength reduction in steam-cured concretes with respect to the corresponding concretes cured at room temperature, is negligible or much lower in mixtures with the ternary combinations of pozzolanic additions.