Gopi Rajamanickam

Compaction and curing both are equally important to achieve the desired strength and durability of concrete. To make concrete with a better surface finish, improved strength, and durability, it is essential to impart self compacting ability to concrete. Curing at an early age is to reduce the plastic shrinkage, to ensure adequate surface strength and surface zone durability. This study examines self-compacting concrete (SCC) that contains saturated light expanded clay aggregate (LECA) and fly ash aggregate (FAA). The effects of LECA and FAA on SCC were examined with flow properties, microstructure, compressive strength, acid resistance (HCl), sulphate resistance (MgSO4), and salt resistance (Nacl). The replacement of fine aggregate in the mixtures ranged from 0% to 25% with 5% interval by volume basis. Water filled LECA and FAA were also combined to produce SCC mixes. The findings demonstrate that substituting saturated lightweight aggregates for fine aggregate in SCC satisfied the filling ability, passing ability, and segregation resistance. The compressive strength of SCC with 15% LECA & FAA, under internal curing is higher by 1.84% & 13.35% higher than that of the control concrete (CMwc) at the age of 28 days. The F15 mix exhibited less weight loss and lesser strength loss in acid & sulphate. Also less weight gain and lesser strength loss in salt resistance. SCC made with LECA & FAA blends to promote internal curing offers technical and cost benefits in the construction industry.

Self-Compacting Concrete (SCC) plays a vital role in the construction sector globally due to the requirements of tall and complex congested structures. River sand is one of the natural key ingredients that has high demand due to the expansion of cities and the growth of population. To overcome this problem researchers from various countries are attempting for alternative materials. In this research, Sugarcane Bagasse Ash Aggregates (SBAA) and Rice Husk Ash Aggregates (RHAA) were utilized to partially substitute of fine aggregate in SCC. The suitability of SBAA and RHAA in SCC is assessed by microstructural characterization and mechanical properties. Three groups of SCC mixes were prepared. Gropup-1 mix contains RHAA about (0%, 5%, 10%, 15% and 20%), Group-2 mix contains SBAA (0%, 5%, 10%, 15% and 20%) and Group-3 mix contains blended RHAA SBAA (each 5%, 10%, 15% and 20%). EFNARC guidelines were used for mix design and assess the rheological characteristics. In all the groups of SCC mixes, 10% replacement of SBAA and RHAA shows significant results. This investigations shows that the blended ash aggregates can be replaced with fine aggregate and considerably can reduce the demand of river sand.

The study aims the performance of presoaked light expanded clay aggregate (LECA) and fly ash aggregate (FAA) as partial replacement of river sand in self compacting concrete (SCC). On a volume basis, presoaked LECA and FAA partially replace river sand. LECA and FAA are presoaked for 24 hours before casting of SCC. The water retained in the lightweight aggregates (LWAs) pores acts as an internal curing reservoir. SCC workability characteristics, including as flowability, filling and passing capabilities, resistance to segregation, and concrete bleeding, were evaluated using slump cones, U-boxes, L-boxes, V-Funnels, and J-ring tests. Addition of LECA and FAA reduces the water for curing and also attain good workability and strength of SCC. The durability characteristics such as sulphate attack, acid attack are conducted in various durations like 7, 28, 56, 90, 180 days. Further, bond strength and accelerated corrosion tests also conducted. From all the mechanical and durability tests on SCC with LECA and FAA by 15% replacement for fine aggregate shows more beneficial effect in strength, microstructural and durability properties than those demonstrated by control mix concrete.