Concreting Workmanship in Indonesia Study Case: Padang City, West Sumatra, Indonesia

Abstract

This research gives information about the practice of concreting work in Reinforced Concrete (RC) building project in Indonesia. The study area is Padang City, which has suffered severe damages due to September 2009 Earthquake. The target interviewee is 100 builders who are constructing RC buildings. This interview together with observation was conducted by directly visiting the construction sites. While collecting information about the main factors which contribute to RC building quality, e.g., concrete mixing, compaction, concrete placing and curing, the information about the profile of the builders have been collected. The results show that the workers dominate the profile of builders in productive age with 30 years experiences on average. However, 90% of the builders yet experience any construction workshop. The concreting work, which is conducted by the builders, yet reaches the required standard. More than 50% of the builders produced concrete with the higher water-cement ratio, and almost 65% admitted that they add more water after concrete`s setting time is finished. There are 3common methods of concrete compaction which is used. 6% of the builders use a vibrator, 43% use the rodding method, 28% use hummer, and 8% choose to add more water to placed concrete to increase concrete workability. Meanwhile, more than 60% of the builders do not cure the placed concrete. The results show that construction practice that is conducted by the local builders is needed to be improved. The mistakes seem to be repeated over a generation since the source of learning of the builders is mainly from their senior builder (77.25%) and self-learning (2.5%). Only 7.5% that admitted they had experienced on construction workshop.

Experimental Study of Masonry Wall Strengthened by Polypropylene Fiber Mortar

“…In Indonesia, the type of wall with masonry dominates compared to other kinds of wall. Based on previous studies, the masonry wall in Indonesia shows a weak compressive strength [5], [6]. This study shows there is a very high vulnerability of buildings using a masonry wall [7].…”

Assessment of Reinforced Concrete Building for Disaster Reduction Strategy in Padang City, West Sumatra, Indonesia

“…Damage patterns based on HAZUS damage criteria were used to judge the damage level of selected buildings. Figure 1 shows the research methodology flowchart : As mentioned before, there are three local compaction methods conducted by local builders in Padang City, by using a vibrator, rodding and hummer [8]. Each compaction methods were applied to fresh concrete mix contained available local materials e,g -aggregates and cement.…”

“…10 cube molds were rodded, and other 10 molds were hitting using hummer for 15 times. The frequency of compaction was based on the information from the builders [8]. Figure 2.e, 2.f, and 2.g show the visual of concrete cube based on standard compaction, rodding compaction and hummer compaction method consequently.…”

“…Meanwhile, some percentage of the builders answered they do not compact the concrete. Some others answered they added more water to increase the workability of the placed concrete [8]. This finding indicated the poor concreting workmanship which can reduce the concrete strength.…”

Internet of Things (IoT) for digital concrete quality control (DCQC): A conceptual framework

“…The stages have been highlighted as concrete production at the batching plant or in-situ at the site, transportation through transit mixers, its placing using vibrators and formwork, curing of concrete, and post-construction structural health monitoring stages. Non curing (Juliafad et al, 2019) Early formwork removal (Rockstroh, 2018;Samouh et al, 2015) Plastic shrinkage (Bella et al, 2017;Ghourchian et al, 2018) Thermal cracking (Bella et al, 2017;Zhao et al, 2019) Early age cracking (Khan, Xu, Castel, & Gilbert, 2018;Safiuddin, Kaish, Woon, & Raman, 2018) Autogenous and drying shrinkage (Gilbert, Castel, Khan, South, & Mohammadi, 2018) 5 Post Construction Reinforcement and concrete corrosion (Shi, 2018;Zhou et al, 2018) Internal crack occurrence and propagation (Cai, Fu, Shang, & Shi, 2018;Dung, 2019) Moisture sensor is placed in the concrete − to monitor water content (to prevent excess addition of water during transportation), workability, and giving realtime data of the chemical characteristics of concrete.…”