This paper describes studies carried out to examine the influence_x000D_ on strength and chloride ingress when Portland cement is replaced_x000D_ with limestone filler. In the chloride ingress study both an_x000D_ accelerated method and field exposure measurements up to one_x000D_ year were employed. The results show that the method of_x000D_ measuring the resistance to chloride ingress can have a major_x000D_ influence on the assessment of the effect of different binders._x000D_ Further, the effect on chloride resistance, when replacing Portland_x000D_ cement with limestone filler is strongly dependent of the_x000D_ replacement ratio. The effect on compressive strength when_x000D_ replacing Portland cement with limestone filler is also strongly_x000D_ dependent of the replacement ratio.
Rice Husk Ash (RHA) is a well-known supplementary cementitious materials (SCMs) that can be used for concrete with reduced CO
2 contributions. In 2016, only Nepal produced 5.2 million tonnes rice that gave about 1.14 million tonnes rice husk. The rice husk can also be used directly in a cement kiln as a fuel. This study analysis the potential CO2 reductions from three scenarios and emphasis strengths, weaknesses, opportunities and treats in the production systems for initiate a decision process with possibilities to get an industry project financed from the green climate found. The highest CO2 benefits were from rice husk used in a cement kiln were half of the yearly rice husk production in Nepal could reduce the climate impact with 808000 tonnes CO2.
During the project ‘The CO2-cycle in cement and concrete’ an analytical model to quantify the CO2-uptake in a country a specified year was developed. That was accomplished by deriving a new model for the carbonation process and as input to that, measurements of carbonation in concrete indoors and studies of carbonation in crushed concrete were made. Through knowledge of the cement production each year, the distribution of the cement into different products and estimations of what concrete quality each product has, the total uptake for Sweden was calculated. For the year 2011 was the CO2-uptake calculated to 300 000 tons.
Sprayed concrete differs from ordinary concrete through application technique and addition of set accelerator that gives immediate stiffening. The alkali free set accelerator consists of sulphate and aluminate and forms an ettringite network that gives a stiff but not hard matrix. This work has investigated the interaction between the early ettringite matrix and the proper cement hydration and the development of the interfacial zone between concrete and rock. This has been correlated to the development of the bond strength.
In fresh concrete, the filler fraction (0-0.125 mm) is of vital importance for workability. With the use of superplasticizer, it is possible today to use quite large amount of fillers. This has made it possible to make self-compacting concrete and other special concretes. How to use the fillers and the amount of fillers depends on the size distribution and quality of the filler. Basically, the filler should be round and the distribution of filler and cement should be continuous. The size shall not overlap too much with that of the cement. Fillers from crushed rocks consist of minerals and the filler particles depend on the mineralogy and texture of the rock type. This work treats different methods, including paste rheology, to evaluate the quality of the filler fraction. By using good quality filler, it is possible to reduce the amount of cement in concrete
In Sweden, the market share of cast-in-place Self-Compacting_x000D_ Concrete (SCC) is only around 10%. Uncertainty concerning_x000D_ formwork pressure is considered to be one of the most important_x000D_ factors explaining the slow progression. During construction of a_x000D_ 400 m long, 6 m high and 0.27 m thick prison wall in northern_x000D_ Sweden, SCC alone was used. The formwork used consisted of_x000D_ steel-framed panels, instrumented with flush-mounted pressure_x000D_ sensors. Each concrete batch was tested for air content, slumpflow,_x000D_ concrete and air temperature. Besides tests on torsional_x000D_ moment or torque, L-box, and V-funnel were carried out._x000D_ Relations between concrete properties, casting rate and time_x000D_ versus formwork pressure were investigated. The results_x000D_ confirmed that structural build-up of SCC has to be taken into_x000D_ account for predicting formwork pressure. The torsional moment_x000D_ was measured at three consecutive times at each casting and the_x000D_ time-dependent development of the torsional moment was_x000D_ subsequently used as indirect input in two simple formwork_x000D_ pressure methods that have been developed recently. The_x000D_ comparison between computed and measured formwork pressure_x000D_ shows that both these methods would be possible to use for_x000D_ predicting formwork pressure generated by SCC.
The overall aim of this project is to develop improved methods for assessment of the load carrying capacity and response of bridge deck slabs. This research project was carried out by laboratory experiments, analytical computational analysis, linear and non-linear finite element analyses. The on-going non-linear analyses of tested slabs show possibility to accurately predict the load carrying capacity and to realistically simulate the crack pattern and load distribution.
The EC funded project SESBE (Smart Elements for Sustainable Building Envelopes) focused on utilizing new types of cementitious materials for reducing the mass and thickness of façade elements while increasing their thermal performance. A method enabling the quantification and verification of the required anchorage length for a given textile reinforced reactive powder concrete (TRRPC) is presented. At the material level, tensile tests were conducted to determine the tensile properties of the reinforcement. Pull-out tests were applied to quantify the required anchorage length, while uniaxial tensile tests were performed to quantify the ultimate strength and verify the suitability of the anchorage length at the composite level. The combination of these methods was deemed useful to determine the overlapping length required for larger scale façade applications.