1. 网友应该知道这个词组：be indicative of。它具有及物动词 indicate （表示出；暗示出）的意义和作用。

2. 省略be 后，是一个形容词词组 indicative of the increased resistance offered by the flocculated structure to the compaction effort，作a gradual reduction 的定语。

3. 而 offered by the flocculated structure to the compaction effort 是过去分词短语，又作了 the increased resistance 的定语。

所以，offered 不是谓语动词，而是过去分词。

句子结构分析：

The admixture of lime or fly ash （主语，中心词是 admixture） resulted in （谓语：导致）a gradual reduction of the maximum dry density （介词in 的宾语，中心词是 reduction）indicative of the increased resistance offered by the flocculated structure to the compaction effort.（定语，修饰reduction。）

4. to the compaction effort 是 reduction 的结果，也是其定语。换成动词，结构则是：

reduce the maximum dry density to the compaction effort

5. offered by the flocculated structure to the compaction effort 又是 resistance 的定语）