Concrete pump hoses are used for suction and discharge of concrete, dry bulk materials and dry cement.
Working temperature range is approximately -25ºC to + 80ºC.
Lining must be abrasion resistant. The abrasion value is measured according to DIN 53516. The lower the measured value the better quality and longer lifetime. The lifetime is measured with volume of the delivered material. Usually natural rubber based compounds are chosen for lining.
Cover must be ozone resistant and also abrasion resistant.Generally synthetic rubber based compounds are chosen for cover.
Reinforcement depends on the pressure needed and inner diameter of the hose. Standard working pressure is 85 bar (1232 PSI) and standard burst pressure is 200 bar (2900 PSI).
Standard inner diameter is 125mm (5 ") and standard lengths are 3m, 4m and 5m.
Also ends are hardened with special techniques and couplings are fixed by crimping. This also prolongs the lifetime of the hose.
General information about concrete: Concrete is one of our most common building materials, it consistates of aggregates binded by cement paste. The compressive strength of concrete is to a large extent dependent on the water to cement ratio (w / c). Cement is a hydraulic binder, meaning it hardens by a reaction with water to something that is not water soluble. The smallest particles of the concrete paste are in the range of micrometers (or even nanometers), the largest particles, the aggregates, are varying several centimeters. The types and proportions of the concrete constituents not only influence concrete's hard properties, but also its fresh properties.
Workability of Concrete: The concrete mix is designed to fit requirements in the hardened state: at the lowest cost possible it has to satisfies standards with respect to surface, shape, strength, durability, shrinkage and creep. There is not only a need for the constituents to be of adequate quality and quantity, but also the concrete functionality is of great importance. Workability may be defined as the amount of work necessary to achieve full compaction, according to Neville (2000). The definition given in ACI (1994) is: 'that property of freshly mixed concrete or mortar which determines the ease and homogeneity with which it can be mixed, placed, consolidated and finished'. Qualitative words to describe concrete capacity are eg concrete flow-ability, compact-ability, stability, finish-ability, pump-ability. These features may be quantitatively measured in terms of consistency, mobility, vicsosity, etc. As presented by Tattersall and Banfill (1983), for any type of casting, it is always important to know the minimum workability required to ensure:
(i) the concrete being satisfactory mixed and transported,
(ii) complete form filling, even in the presence of awkward sections and congested reinforcement,
(iii) adequate compaction to expel excessive air voids and
(iv) good surface finish without honeycombing or numerous blowholes as well as the ability of giving the concrete a nice finish.