Author : Nghi L.B. Le,Piet Stroeven
Publisher : Elsevier Inc. Chapters
Release : 2012-11-12
ISBN : 0128090391
Language : En, Es, Fr & De
Book Description :
Portland cement (PC) production contributes by about 6% to global emissions of C02. Reduction of the PC content in the binder exerts therefore a direct positive effect on such emissions. Partial replacement of the Portland cement by pozzolanic mineral admixtures has been proven a possible option. The green character is even reinforced by making use of incinerated vegetable waste, such as rice husk ash (RHA). Moreover, as a result of the gap-grading effect on particle packing density with RHA as the fine component, high strength concrete can be achieved with RHA-blended cement. This has been published earlier, so the paper only briefly covers these aspects. Characteristics of the capillary pores developed in the hydrating binder have direct impact on the transport-based durability properties. However, assessment of such pore characteristics of the RHA-blended cement constitutes a complicated problem, especially in experimental approaches. This paper, therefore, presents a new economic approach to conduct such investigation on the realistically produced cementitious materials in virtual reality. The fresh packed state of the paste’s particles is simulated by a discrete element modeling (DEM) system, HADES. The hydration of a (blended) cement is simulated by a so-called ‘extended integrated particle kinetics model’ (XIPKM). Pore characteristics, such as topology, location distribution, degree of percolation and fraction of main channels in the pore network, are explored by a new modern approach named ‘double random multi-tree structuring’ (DraMuTS). The size distribution of throats that significantly limit the transport in the pore network system is derived from star volume measurements. Four examples of plain PC and of RHA-blended PC with two w/b ratios are presented. The expected positive effects on transport-based durability issues due to RHA-blending are discussed.