the strength of concrete is a function of the proportions of the constituent materials, namely, cement, water, fine and coarse aggregates. the conventional methods used to determine the mix proportions that will yield the desired strength, are laborious, time consuming and expensive. in this paper, a mathematical method based on modified regression theory is formulated for the prediction of con...

rice husk ash (rha) is natural pozzolan containing reactive silica and/or aluminum. when the material is mixed with lime in powdered form and in the presence of water, it will set and harden like cement. this work uses osadebe’s optimization model to optimize the shear modulus of concrete made from rha. the strengths predicted by the model are in good agreement with their corresponding experime...

this paper deals with the interfacial effects of silica fume (sf) and styrene-butadiene polymer (sbr) on compressive strength of concrete. analyzing the compressive strength results of 32 concrete mixes performed over two water-binder ratios (0.35, 0.45), four percentages replacement of silica fume (0%, 5%, 7.5%, 10%) and four percentages of sbr (0%, 5%, 10%, 15%) were investigated. a mathemati...

The addition of steel fibers into concrete improves the postcracking tensile strength of hardened concrete and hence significantly enhances the shear strength of reinforced concrete reinforced concrete beams. However, developing an accurate model for predicting the shear strength of steel fiber reinforced concrete (SFRC) beams is a challenging task as there are several parameters such as the co...

superior performances of self-compacting concrete (scc) in fresh state to achieve a more uniform distribution encourage the addition of fibers in concrete which is a motivation for structural application of fiberreinforced concrete. fiber addition reduces the workability of self-compacting fiber reinforced concrete (scfrc). to provide required workability of the scfrc, more paste is needed in t...

The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the ty...

Lightweight concrete (LWC) is a kind of concrete that made of lightweight aggregates or gas bubbles. These aggregates could be natural or artificial, and expanded polystyrene (EPS) lightweight concrete is the most interesting lightweight concrete and has good mechanical properties. Bulk density of this kind of concrete is between 300-2000 kg/m3. In this paper flexural strength of EPS is modeled...

a new model is proposed for two-dimensional simulation of the concrete fracture in compression. the model generated by using the voronoi diagram method and with considering random shape and distribution of full graded aggregates at the mesoscopic level. the aggregates modeled by combining irregular polygons, which then is placed into the concrete with no intersection between them. by this new m...