Abstract:

Orthogonal experiments were carried out to study the influence of several factors on the impermeability and compressive strength of the mortar.These factors include not only three kinds of water reducers,that is,the modified calcium lignosulphonate high-range water reducer GCL1-3A,calcium lignosulphonate water reducer and naphthalene high-range water reducer FDN,but also dosage of water reducer,water-cement ratio,cement-sand ra-tio and the grade of cement.The experimental results show that water reducers have the most significant influence on the imperm eability and compressive strength,and that greater compressive strength and imperm eability can be obtained by adding 0.4% (mass fraction)GCL1-3A into the mortar with a water-cement ratio of 0．435 and a ce-ment-sand ratio of 1:2.5,and the open porosity and pore homogeneous degree of the mortar respectively reach 1 7.06% and 0.46，while those of the blank mortar is respectively 20.56%and 0.17.Moreover,it is primarily indi-cated that the durability of concrete improves due to the improvement of spatial steric hindrance and electrostatic re-pulsive force which increase the dispersion and anti-coagulation ab ilities.

Key words: mortar, modified calcium lignosulphonate, high-range water reducer, imperm eability, compressive strength