The polymer coil whose size is comparable in solution to particle diameter makes a flexible bridge between two particles. The steady shear viscosity, dynamic viscoelasticity, and first normal stress difference were measured for suspensions flocculated by the bridging mechanism. When the particle concentration is increased above some critical level, the flow becomes shear-thickening in a narrow range of shear rates. The shear-thickening behavior results from the rapid extension of a network of unbounded flocs consisting of particles bridged by flexible coils. The first normal stress difference is coupled with the elastic properties of suspensions. The relation between the elastic properties and network formation process is discussed on the basis of percolation theory. A power law dependence of elasticity on the difference of particle concentration from the percolation threshold is established through the scaling rule. The critical exponent is estimated to be 1.7 and in good agreement with an isotropic elastic constant model. The factor controlling the critical behavior for elastic percolation is the vector nature of bonds which can be connected with the conformation of bridges. (C) 1994 Academic Press, Inc.