Cement Paste

Rice husk ash (RHA) has been used as a highly reactive pozzolanic material to improve the microstructure of the interfacial transition zone (ITZ) between the cement paste and the aggregate in high-performance concrete. Mechanical experiments of RHA blended Portland cement concretes revealed that in addition to the pozzolanic reactivity of RHA (chemical aspect), the particle grading (physical aspect) of cement and RHA mixtures also exerted significant influences on the blending efficiency. The relative strength increase (relative to the concrete made with plain cement, expressed in %) is higher for coarser cement. The gap-grading phenomenon is expected to be the underlying mechanism. This issue is also approached by computer simulation. A stereological spacing parameter (i.e., mean free spacing between mixture particles) is associated with the global strength of the blended model cement concretes. This paper presents results of a combined mechanical and computer simulation study on t...

The paper presents the results of a hydration study performed in order to explain the significant increase in compressive strength at one day of age observed on steam cured mortars when 25% by mass of cement was replaced with a metakaolin. Two CEM I 52.5R cements, differing in reactivity, and a metakaolin (MK) were used. By means of XRD and

Abstract: An Engineered Cementitious composite is an ultra ductile cementitious composite which is highly crack resistant, with a tensile strain capacity over that of normal concrete. Engineered Cementitious Composites is similar to Fiber Reinforced Concrete. FRC contains water, cement, fine and coarse aggregate, fiber, and some common chemical additives. But only difference between FRC and ECC is, in ECC coarse aggregates are not used as they tend to adversely affect the unique ductile behavior of the composite. Polypropylene fibers have advantageous characteristics, the weak bond with the cement matrix as a result of their smooth surface and chemical inertness remains a large limitation. It has been demonstrated that the fiber-matrix bond strongly affects the ability of fibers to stabilize crack propagation in the matrix. As the bond between fiber and matrix is mainly mechanical, it seems that incorporating silica fume into fiber reinforced cement composites provides a better bond with the matrix through pore refinement and better distribution of the hydration products. Hence, in this project an effort was made to study the effect of PP fibers on the mechanical properties of mortars incorporating silica fume. Six fiber volume fractions 0%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% were considered. The experimental study is to present the behaviour of prism with optimum percent of fibers under two point loading.
Keywords: Engineered Cementitious Composites, polypropylene fiber, cement paste, silica fume, and properties of concrete.
Title: Experimental Investigation of Polypropylene Fiber in Engineered Cementitious Composites
Author: Ms.E. Ramya, Ms. S. Nalini, Mrs. S. Sivaranjini, Mr. R.M. Saravanakumar
International Journal of Civil and Structural Engineering Research
ISSN 2348-7607 (Online)
Research Publish Journals

The packing characteristics of the cementitious materials have great influence on the performance of a concrete mix, but there is so far no generally accepted method of measurement. Herein, a new method, called the wet packing method, is developed. It mixes the cementitious materials with water and then measures the apparent density and voids content of the resulting mixture at

The wet packing method developed in Part 1 [Wong HHC, Kwan AKH (2007) Packing density of cementitious materials: part 1 measurement using a wet packing method. Mater Struct (Paper No. MAAS3281)] has been successfully applied to measure the packing densities of cementitious materials containing ordinary Portland cement (OPC), pulverised fuel ash (PFA) and condensed silica fume (CSF). The test results for