Concrete international 

About: Concrete international is an academic journal. The journal publishes majorly in the area(s): Precast concrete & Compressive strength. It has an ISSN identifier of 0162-4075. Over the lifetime, 2175 publications have been published receiving 24938 citations.

Reducing the Environmental Impact of Concrete

Abstract: Almost all concrete in current use contains Portland Cement. This cement is produced in a process which involves heating the raw materials to 1400C which makes them produce large quantities of carbon dioxide as a product of a chemical reaction. For every 1000kg of cement produced just over 500kg of carbon dioxide arises from the chemical reaction and a further 250400kg from the energy use. These quantities cannot be reduced.

Self-Compacting High-Performance Concrete

Abstract: 1. Characteristics Self-compacting high-performance concrete is a high performance concrete that can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction (Fig. 1). This concrete is defined as follows at the three stages of concrete: (1) Fresh: selfcompactable; (2) Early age: avoidance of initial defects; (3) After hardening: protection against external factors.

Mixture Proportioning for Internal Curing

Abstract: Internal curing is the process by which the hydration of cement occurs because of the availability of additional internal water that is not part of the mixing water. An equation has been developed in a previous study for calculating how much lightweight aggregate (LWA) is needed to supply water for internal curing of any given concrete mixture. This paper presents refinements for estimating the parameters of this equation that will provide a readily recognized means of choosing the proper amount of LWA and improving mixture proportioning. The two major factors to be considered are the variation of chemical shrinkage of cement with Portland cement phase composition and curing temperature, and the relevant value for the absorption of the LWA. In order to determine the amount of LWA needed, it is recommended that the mass composition of the cement clinker be obtained from either a detailed scanning electron microscope/X-ray image analysis or the Bogue calculation. Then, the expected chemical shrinkage of the cement at 25 deg C should be calculated. If the expected average curing temperature is above 25 deg C, the calculated value should be decreased by 0.0005 per deg C above 25 deg C. If the expected average curing temperature is below 25 deg C, the calculated value should be increased by 0.0005 per deg C below 25 deg C. The desorption of the LWA from a saturated state down to a relative humidity of relevance for the internal curing of concrete should then be measured. Finally, the determined values for chemical shrinkage and absorption of LWA should be substituted in the original equation to obtain the desired mass of lightweight fine aggregate in the concrete mixture.