Seasoning of Timber When a tree is newly felled, it contains about 50% or more of its own weight as water. This water is in the form of sap and moisture. The water is to be removed before the timber can be used for any engineering purpose. In other words, the timber is to be … Read more
Ribbed Tor Steel Bars This is a type of deformed high strength steel. These bars are manufactured by controlled cold twisting of hot rolled bars. These bars have ribs or projection on their surface. The ribbed tor steel bars are available in different sizes varying 6mm to 50 mm in diameter. These bars are commonly … Read more
Compaction should not be confused with consolidation. At the end of the consolidation and/or compaction process, a closer packing of soil grains results, which leads to increased shear strength and decreased compressibility and permeability. Difference Between Compaction and Consolidation Soil Compaction It is a dynamic process Compaction is almost instantaneous Densification is due to reduction … Read more
Why to Use Clean Sand for Mortar? Contaminated sand will not bind with cement, hence is weakening the mortar. Also sand with high percentage of clay or silt will weaken the mortar, because the clay or silt contains too many fines that needs to be covered by cement for proper binding. Why Use Fresh Cement … Read more
Steels should be stored in such a way, so as to avoid distortion and to prevent deterioration and corrosion. Steels of different classes should be stored separately. Follow the guidelines given below while storing steel on site. Storing of Steel Reinforcement Store bars of different classes, sizes and lengths separately to facilitate issues in such … Read more
While sampling cement from a lot (consisting of a number of cement bags), the lot is divided into a number of sub-lots. Number of sub-lots into which a lot is to be divided is depends upon the weight of the lot. Use the following table while dividing the lot into sub-lots. Weight of the lot … Read more
Packing and Marking of Aggregate Sample Before dispatching, each sample of aggregate is packed separately in such a way so as to prevent loss of any fine material. Use container or sample bag to pack coarse aggregate. Use tight container or closely woven bags to pack fine aggregate and all-in-aggregate; so that there is no … Read more
Sampling of Fresh Concrete To ensure it is representative of the whole truck load, a standard sample consists of scoopfuls taken from different parts of the batch and collected in bucket. Scoopfuls must be taken through the moving stream, as the load is discharged, sampling the whole width and depth (not just the top part). … Read more
Effects of Hot Weather on Concrete Any operation of concreting done at atmospheric temperature above 400C may be put under hot weather concreting. The effect of hot weather may be as follows: Accelerated setting: A higher temperature of fresh concrete results in a more rapid hydration and leads to reduced workability/ accelerated setting. This reduces … Read more
Objective Determination of unit weight or bulk density and void of aggregates. Equipments Name Capacity 1. Balance Sensitive to 0.5% of weight of material 2. Cylindrical metal measure Of 3 litre capacity (for fine aggregate) Of 15 litre capacity (for aggregate upto 40mm) 3. Tamping rod 16 mm dia. and 60 cm long Sample Preparation … Read more