生活垃圾焚烧发电产生的飞灰及许多工业废弃物都含有大量重金属元素,给环境带来严重危害.本研究以碱激发剂与飞灰等含重金属元素废渣制成非烧轻骨料,通过形成沸石型的水化硅铝酸盐,把重金属固化在骨料中.检测证明,完全能满足国家相关标准要求.同时可将该骨料与矿粉(或粉煤灰等)、碱激发剂配制成混凝土,生产砌块及排水管等制品,节省资源和成本.

由于矿物质粉体和减水剂技术的发展,出现了高性能与超高性能混凝土;而自密实混凝土的出现则改变了混凝土结构与构件的生产技术及工艺,将超高性能混凝土与自密实混凝土技术结合研发超高性能自密实混凝土.采用新材料新技术生产的C80混凝土预应力管桩经12h脱模混凝土抗压强度>45MPa,可承受张拉预应力,3d养护后抗压强度达90～95MPa;采用免蒸养、免蒸压的"双免"工艺达到了节能目的.通过泵送浇筑、自密实成型生产排水管改变了振动、离心辊压的生产技术,给混凝土技术带来了变革与创新.

The composition and properties of UHp-SCC are introduced. The self-compacting, the self-shrinkage cracking and the high temperature explosion are the key technologies of UHp-SCC. The difficulty of high pumping technique is to preserve plasticity, reduce viscosity and self-compactness. UHp-SCC has good technique and economical effect and development prospect.

依托广州周大福金融中心项目,通过原材料的优选、特种外加剂的创新研发、各掺量的优化配合比技术、多种掺和物的相互作用机理,研发了具有低发热、低收缩、高强度、高保塑、高泵送、自密实、自养护性能的超高层高适应性绿色混凝土,保证了C80高强混凝土与双层劲性钢板剪力墙结构联合工作,有效避免了双层钢板强约束下C80高强混凝土墙体裂缝的出现.

The high strength and high performance concrete C80~C100 is popularly used nowadays, especially in the West-Tower Project of Gungzhou. In order to provide reference for the use of high strength concrete and the development of ultrahigh pumping technology, the following six aspects were studied, namely the preparation of high strength concrete, the variation of the concrete mixture under high pressure, the index of the ultrahigh pumping concrete, the change after the pumping, the loss of the pumping pressure and the measurement of the pumping viscous resistance.

With the development of modern building design and construction technology, high strength concrete technology were getting more use in engineering and more requirements. The authors produced C80 HPC by using Portland cement, blast furnace slag, micro bead and Flyash as cementitious material, have prepared the concrete with grade of C80, low pumping resistance (rewinding time less than 6s), low shrink (72h early self-shrinkage value at 0.028%), high workability (slumps over 240mm and divergence over 700mm) and high durability (diffusion coefficient in concrete after 28d was 1.35×10-12 m2/s), which would match the requirements of the Guangzhou East Tower.

The paper studied the effects of single addition of ultrafine fly ash (UFA) and mixed addition of silica fume ultrafine fly ash (SF-UFA) on powder pressure entity dense packing density, mechanical performance and microstructure structure of composite cement paste. The results show that, the ternary system of mixed addition of SF-UFA can effectively further reduced the compacting voidage and more increased packing density of composite powder, compared with the binary system of single addition of UFA. And when the content of SF is 8%, the compacting voidage is the lowest. Next, in the ternary system of mixed with silica fume, ultrafine fly ash and cement (SF-UFA-C), with the increase of silica fume (SF), the total porosity and pore diameter of hardened cementing paste decreased further compared with binary system, and with 8% content of SF and 17% content of UFA, the total porosity of hardened cement paste is the lowest, decreased by 60% than that of reference sample. At last, mixed addition of SF-UFA can improve the long-term strength of composite cement paste either, the compressive strength of 60 days' hydration increased by nearly 9% compared with UFA-C and increased 41% compared with the reference sample.

The influence of a chloride-ion adsorption agent (Cl agent in short), composed of zeolite, calcium aluminate hydrate and calcium nitrite, on the ingress of chloride ions into concrete and mortar has been experimentally studied. The permeability of concrete was measured, and the chloride ion content in mortar was tested. The experimental results reveal that the Cl agent could adsorb chloride ions effectively, which had penetrated into concrete and mortar. When the Cl agent was used at a dosage of 6% by mass of cementitious materials in mortar, the resistance to the penetration of chloride ions could be improved greatly, which was more pronounced when a combination of the Cl agent and fly ash or slag was employed. Such an effect is not the result of the low permeability of the mortar, but might be a result of the interaction between the Cl agent and the chloride ions penetrated into the mortar. There are two possible mechanisms for the interaction between the Cl agent and chloride ion ingress. One is the reaction between calcium aluminate hydrate in the Cl agent and chloride ions to form Friedel’s salt, and the other one is that calcium aluminate hydrate reacts with calcium nitrite to form AFm during the early-age hydration of mortar and later the NO2− in AFm is replaced by chloride ions, which then penetrate into the mortar, also forming Friedel’s salt. More research is needed to confirm the mechanisms.

Ultra-high strength concrete (including the coarse aggregate of over 5mm), with high compressive strength and strong durability, is regarded as a new-type building material that could economize on raw materials, land and energy and the development trend of concrete technology both at home and abroad. However, the large consumption of binding materials, low water-binder ratio and the viscous mixture are prone to give rise to the inferior pumping capacity, pipe blockage and pipe break, thus preventing its massive application in the real projects. Therefore, through the design of reasonable mixture ratio, this paper makes up and produces the pumping ultra-high strength concrete of over 100MPa that contains coarse aggregate by adopting the compound design of mineral admixtures, such as slag powder, fly ash and ganister sand so as to optimize the relevant parameter of the mixture ratio. Finally it comes to the conclusion that while making up the ultra-high strength concrete of over 100MPa, it is much more reasonable to appropriately add the mixing amount of the mineral admixtures, increase the water-cement ratio and decrease the water-binder ratio.

Combining with the project actual demands,a multifunctional high performance concrete is invented to change the concrete construction process,and the aim of long construction life,energy-saving,low carbon,environmental protection for high performance concrete is achieved finally.The characteristics of high performance concrete is introduced.The cracking problem of the shear walls with C80 concrete is researched with the project of Guangzhou East Tower.The mix proportion of high performance concrete is optimized.A serial tests are researched from the performance of new pouring concrete,compressive strength,early shrinkage and autogenous shrinkage,temperature rise of hydration,maintenance conditions.Then the good characteristics of high performance concrete are obtained.

Self-compaction concrete is a new green concrete featuring self-leveling, self-compaction, low noise and low consumption of labor force. Nowadays, a large number of super high-rise buildings (h>400m) are under construction around the world, the complicated structures and dense reinforcement placement has brought numerous inconveniences to construction of concrete. Research on high strength / ultra-high strength self-compaction concrete thus becomes a hotspot. The porous structure of zeolite powder can help absorb the water reducing agent and then release it slowly in concrete mixture. With the low slump loss it produces, the prepared C100UHP-SCC can resist slump loss for over 3 hours. Test of super-high pumping at a height of 411m is carried out in the West Tower program at Pearl River New Town of Guangzhou (the building height is 441m). Drilled core test for L-shaped component indicates a dense internal structure, so it has a desirable self-compaction and capacity to pass through dense reinforcement.

In order to study the mechanical behavior of C120 RC beam with addition of polypropylene fibres and bending tests of 12 such beams were carried out.It turned out that polypropylene fiber did not affect crack resistance of sample in the existing content.With the increases of polypropylene fiber content for two kinds of reinforcement concrete members,the plastic deformation stage was slightly extended,but the improvemant on ductility improvement was not obvious.

The concrete technology has seen great improvement with the construction of large numbers of ultrahigh buildings at a height of more than 400 meters worldwide. It has been a research hotspot in the field of concrete recently to discuss how to reduce pumping resistance, avoid pumping block and meet the requirements of ultrahigh pumping (h>400m), especially the challenge of the ultrahigh pumping of HS & HP concrete with larger pumping resistance. This paper researches the selection of raw materials and design of mix proportion of C80 concrete used in the construction, and introduces the workable evaluation index, pumpability and pumping project in relation to the ultrahigh pumping of C80 concrete mixture, according to the construction requirements of the one-off pumping height (412 meters) for the C80 HS & HP concrete used in West Tower Project of Zhujiang (Pearl River) New Town in Guangzhou-- the tallest building in South China Region of mainland China.

Along with the rapid development of China and its eye-catching economic take-off, industrial production has brought about increasingly enormous negative impact. Industrial residues (coal ash, iron-ore slag, phosphorous slag and ganister sand) have accumulated in large quantities, thus severely contaminating the environment and greatly restricting the sustainable economic development. This paper conducts research on microstructure of the industrial wastes that are massively applied in domestic architectural material industry, such as coal ash, (S95S105) slag powder, S75 phosphorous slag, micro-bead (ultra-fine coal ash) and the micro ganister sand so as to analyze its size distribution and particle appearance and introduce its functions and effect in concrete and other cement products.

With development of concrete technology, the self-compaction concrete, as a green material, has been studied and widely applied thanks to its characteristics like self-leveling, self-compacting and desirable fillability. At present, high performance and ultra-high performance is an important trend in development of self-compaction concrete technology. Working performance, physical performance, endurance quality, ultra-high pumpability and microstructure of C100UHP-SCC are studied in this paper. The initial fluidity of studied UHP-SCC reaches above 550mm and maintains for 3h without loss, its compressive strength on 28d is more than 100MPa, which can ensure the architectural structure to last for 100 years and enable ultra-high pumping over 400m. The technical parameters mentioned above provide valuable reference for design and construction of super high-rise buildings which are above 1000m.

The paper studied the effects of different contents of beads on powder pressure entity dense packing density, mechanical performance of composite cement paste. The microstructure of the composite paste is researched by SEM analysis and nitrogen adsorption method. The results show that when the beads content is low, the compacting voidage decreases with the increased bead contents. When the beads content is 30%, composite cementing material achieves the densest packing density. The compacting voidage of composite cement powder has strong correlation with the pore structure and strength of hardened cement paste. When the compacting voidage value reaches minimum, the average pore radius and maximum pore radius of hardened cement paste reach the minimum values. In addition, the 28d strength of composite cement paste is higher than ordinary cement paste.

On the basis of the C120 concrete with ultra-high strength,polypropylene fibre was added and such tests were taken for concrete as early shrinkage,breaking performance,splitting and tensile strength,brittleness cracking under high temperature.It turned out that the development of concrete crack was limited by polypropylene fiber;as the increases of fiber volume fraction,the toughness of concrete was improved.The splitting and tensile strength and the ratio of tension and pressure were also increased for C120 polypropylene fiber concrete,the brittleness of concrete was improved obviously.The high temperature embrittlement of explosion had been overcome,which made C120 ultra-high strength concrete obtain high performance.

Fire resistance of ultrahigh-performance concrete was measured under different temperatures and loadings. C120 concrete was prepared with 1 kg/m3 organic fiber and C120 concrete with 2 kg/m3 organic fiber and tested under loading at 30% ultimate strength when exposed to high temperatures of 200°C, 300°C, and 400°C, respectively.

By adding polypropylene fiber, fracture toughness of C120 ultra-high-performance concrete in Kingkey Financial Center project has been enhanced. The tests conducted by the Building Material Lab of the Civil and Water Conservancy Institute of Tsinghua University provided satisfactory results of mechanical property and fracture toughness of C120 ultra-high-performance concrete.

With the constantly increasing height of the ultra-high-rise buildings in the world, the high pumping technology of high-performance concrete has become the feature of the constructions. This article has briefly introduced the preparation technology of the high-performance concrete in the world, then elaborated some key technologies such as the mixture ratio and mixture properties of high-performance concrete combining the West Tower project in Guangzhou Pearl River New Town (building height: 440.7m) contracted by Fourth Engineering Bureau of Chinese Construction.