The effect of Polynaphthalene Sulfonates on the mixture composed of Air-entraining cement and fine sand with a maximum size of 600 micron

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This study provides a new mixture using Poly Naphthalene Sulfonates (PNS) to improve the compressive strength, density, and flowability. An experimental study was conducted to study the effect of PNS on mixtures composed of air-entraining cement, fine sand with a maximum size of 600 µm, and low water content, the water to cement ratio was 0.3. The effect of PNS was evaluated based on three characteristics, namely the compressive strength, the density, and the flowability. Four different dosages of PNS (0.0%, 2.5%, 3.5%, and 4.5%) (g/g) of cement weight were used. The results showed that the more PNS dosages were added, the higher compressive strength, density, and flow became. The first mixture without PNS dosages (control mixture) showed no sign of flow resulting in the lowest density and strength among other mixtures. By adding (2.5%, 3.5%, 4.5%) of PNS dose, described as a gram of the superplasticizer to gram of cement, to the control mixture, the compressive strength increased by (58%, 69%, and 70%) compared to the control mixture, and the density increased by (7%, 12%, and 16%) and the flow diameter increased by (17%, 41%, and 52%), respectively. Adding PNS with air-entraining cement can significantly increase the workability, density, and compressive strength altogether. Increasing the compressive strength to above 20 MPa and reaching to 24 MPa may refer to the consent of this combination, PNS and air-entraining cement. To overcome the high-water demand of highly fine sand mixtures made with low water content, water surface tension can be diminished but with no ability to air-entraining or with no ability to retain air-bubbles that may be entrained.