This study investigates the potential of a blended binder formulated from two industrial solid wastes viz. phosphogypsum and fly ash in combination with lime. Three mix proportions of phosphogypsum and fly ash were investigated, and the minimum lime contents required for activation were determined using the Eades and Grim pH test. The lime-fly ash-phosphogypsum blends were then cast into cubes, both in their paste form as well as mortar form, mixed with sand in the ratio of 1:3. They were cured for a period of seven days, and afterwards, their compressive strength was determined. Ordinary Portland cement and lime mortar blocks were also cast as control specimens for comparative evaluation of the strength. The optimal lime-fly ash-phosphogypsum blend was identified and used to construct a masonry prism, and the strengths of the masonry prisms were also evaluated. The optimal lime-fly ash-phosphogypsum blend mortar was also subjected to an X-ray diffraction analysis to determine the reaction products formed during hydration. The study revealed that 5% lime mixed with fly ash:phosphogypsum in the ratio of 3:1 was the optimal proportion which gave the maximum strength to the cubes. The optimal lime-fly ash-phosphogypsum blend mortar developed strength that was higher than conventional Portland cement and lime mortar. The optimal lime-fly ash-phosphogypsum blend mortar masonry prisms developed strength that was comparable to that of Portland cement mortar masonry. The X-ray diffraction analysis revealed the formation of calcium silicate hydrate minerals as well as ettringite and portlandite which were responsible for strength gain.

中文翻译：

---

石灰活化粉煤灰-磷石膏混合物作为低成本替代粘合剂。

本研究调查了由两种工业固体废物配制的混合粘合剂的潜力，即。磷石膏和粉煤灰与石灰结合。研究了磷石膏和飞灰的三种混合比例，并使用 Eades 和 Grim pH 测试确定了活化所需的最低石灰含量。然后将石灰-粉煤灰-磷石膏混合物浇铸成立方体，无论是糊状还是砂浆状，与沙子以 1:3 的比例混合。将它们固化 7 天，然后测定它们的抗压强度。普通波特兰水泥和石灰砂浆块也被浇铸作为对照样品，用于强度的比较评估。确定了最佳的石灰-飞灰-磷石膏混合物并用于构建砌体棱镜，并且还评估了砌体棱镜的强度。还对最佳石灰-飞灰-磷石膏混合砂浆进行了 X 射线衍射分析，以确定水合过程中形成的反应产物。研究表明，5% 的石灰与粉煤灰：磷石膏以 3:1 的比例混合是使立方体具有最大强度的最佳比例。最佳石灰-粉煤灰-磷石膏混合砂浆的强度高于传统的波特兰水泥和石灰砂浆。最佳石灰-粉煤灰-磷石膏混合砂浆砌体棱柱的强度可与波特兰水泥砂浆砌体相媲美。X 射线衍射分析表明形成了水合硅酸钙矿物以及钙矾石和硅酸盐，它们是强度增加的原因。还对最佳石灰-飞灰-磷石膏混合砂浆进行了 X 射线衍射分析，以确定水合过程中形成的反应产物。研究表明，5% 的石灰与粉煤灰：磷石膏以 3:1 的比例混合是使立方体具有最大强度的最佳比例。最佳石灰-粉煤灰-磷石膏混合砂浆的强度高于传统的波特兰水泥和石灰砂浆。最佳石灰-粉煤灰-磷石膏混合砂浆砌体棱柱的强度可与波特兰水泥砂浆砌体相媲美。X 射线衍射分析表明形成了水合硅酸钙矿物以及钙矾石和硅酸盐，它们是强度增加的原因。还对最佳石灰-飞灰-磷石膏混合砂浆进行了 X 射线衍射分析，以确定水合过程中形成的反应产物。研究表明，5% 的石灰与粉煤灰：磷石膏以 3:1 的比例混合是使立方体具有最大强度的最佳比例。最佳石灰-粉煤灰-磷石膏混合砂浆的强度高于传统的波特兰水泥和石灰砂浆。最佳石灰-粉煤灰-磷石膏混合砂浆砌体棱柱的强度可与波特兰水泥砂浆砌体相媲美。X 射线衍射分析表明形成了水合硅酸钙矿物以及钙矾石和硅酸盐，它们是强度增加的原因。