dolos, and the fabrication of reinforced or prestress concrete piles all 

 require specially designed handling equipment. This equipment may or may not 

 have a reuse capability. 



(d) Steel . Most conventional steel shaped units can be handled 

 by conventional construction equipment. However, specially designed units, 

 very heavy units, or some types of underwater placement may require handling 

 equipment specifically designed for that particular job. 



(e) Wood . Conventional construction equipment can usually 

 transport and handle wood members. However, some types of chemical treatment 

 may require special equipment to effectively penetrate the cells. 



(f) Asphalt . For transport and use of asphalt, special heating 

 or hot asphalt handling equipment may be required. If asphalt is placed under 

 water, specially designed handling equipment will be required. 



(g) Synthetics . Special handling equipment may be required for 

 placement of synthetic materials, particularly for underwater placement; 

 however, great weights are not usually involved and the equipment can 

 usually be made or adapted in the field. 



5. Compatibility With Other Materials . 



Problems in compatibility may be physical, chemical, or a matter of 

 esthetics. For composite structures composed of more that one material, 

 such as reinforced concrete, the compatibility of the constituent materials' 

 properties must be considered. Steel of high tensile strength and concrete 

 of high compressive strength used properly together result in a substan- 

 tially improved structure, while asphalt with high adhesive properties to 

 aggregate can create high wear resistance and a cohesive structure. 



Materials may not be compatible due to abrasion effects, particularly 

 between different materials, or even between the same materials (i.e., two 

 stones of different hardnessess may not be compatible in the same struc- 

 ture) . Combining flexible with nonflexible structural units may lead to 

 incompatibility. Materials with major differences in shrink-swell or 

 expansion-contraction coefficients may induce physical stress. The weight 

 of heavy structural units on a fragile substructure may cause failure. All 

 these are generally stress, fatigue, or abrasion problems. 



Chemical incompatibility is particularly critical in the choice of 

 cement and aggregates, selection of synthetics, use of asphalt, electrolysis 

 or corrosion of steel members, and corrosive interaction of dissimilar 

 metals. The effect of incompatibility of materials may take a long time to 

 appear and, if chemical action is allowed to continue, can result in 

 structural failure. 



Compatibility of traditional methods or materials with new and sometimes 

 untried construction techniques with a short experience record, must be 

 carefully considered. 



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